1

                                                                    EXHIBIT 3

                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION


         The undersigned officer of CABOT CORPORATION, a corporation organized
and existing under the General Corporation Law of the State of Delaware, does
hereby certify:

         FIRST: That at a meeting of the Board of Directors of CABOT CORPORATION
held on November 10, 1995, a vote was duly adopted setting forth a proposed
amendment to the Certificate of Incorporation of said corporation, declaring
said amendment to be advisable and directing that said amendment be considered
at the Annual Meeting of Stockholders. The vote setting forth the proposed
amendment is as follows:

                  "VOTED: That the Board of Directors of Cabot Corporation
         hereby approves and declares advisable the following amendment of the
         Certificate of Incorporation of Cabot Corporation, and directs that
         said amendment be considered at the Annual Meeting of Stockholders of
         Cabot Corporation to be held on March 7, 1996, or any adjournment or
         postponement thereof:

                  Article FOURTH of the Certificate of Incorporation is hereby
         amended by striking out the first paragraph thereof, which now reads as
         follows:

                  'FOURTH:   The total number of shares of common stock which 
         this corporation shall have authority to issue is eighty million shares
          and the par value of each of such shares is one dollar ($1.00)
         amounting in the aggregate to eighty million dollars ($80,000,000).'

         and inserting the following in place thereof:

                  'FOURTH:   The total number of shares of common stock which 
         this corporation shall have authority to issue is two hundred million 
         shares and the par value of each of such shares is one dollar ($1.00) 
         amounting in the aggregate to two hundred million dollars 
         ($200,000,000).' "

         SECOND: That thereafter, pursuant to a vote of its Board of Directors,
the Annual Meeting of Stockholders of said corporation was duly called and held
on March 7, 1996, upon notice in accordance with Section 222 of the General
Corporation Law of the State of Delaware at which meeting the necessary number
of shares as required by statute to adopt said amendment was voted in favor of
the amendment.
   2
         THIRD: That said amendment was duly adopted in accordance with the
provisions of Section 242 of the General Corporation Law of the State of
Delaware.

         IN WITNESS WHEREOF, I have executed and subscribed this certificate and
do affirm the foregoing as true under penalties of perjury this 12th day of
March, 1996.



                                                      /s/  Kennett F. Burnes
                                                      _________________________
                                                      Kennett F.Burnes
                                                      President




Attest:



/s/ Charles D. Gerlinger
________________________
Charles D. Gerlinger
Secretary




   3
                                                                   EXHIBIT 3 (a)
                                                                   -------------


                     RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                               CABOT CORPORATION
                    (Originally incorporated July 14, 1960)

          Pursuant to Section 245, Subchapter VIII, Chapter 1, Title 8

                                     of the

                      General Corporation Law of Delaware

        CABOT CORPORATION, a corporation organized and existing under the
General Corporation Law of the State of Delaware, by authority of its Board of
Directors set forth in a vote duly adopted on October 14, 1983, restates and
integrates its Certificate of Incorporation to read in full as herein set
forth:

        FIRST:  The name of this corporation is


                               CABOT CORPORATION


        SECOND:  Its principal office in the State of Delaware is located at
No. 100 West Tenth Street, in the City of Wilmington, County of New Castle. 
The name and address of its resident agent is The Corporation Trust Company,
No. 100 West Tenth Street, Wilmington, Delaware 19801.

        THIRD:  The nature of the business of this corporation and the objects
or purposes to be transacted, promoted and carried on by it are as follows:
   4


        1.   To acquire, by merger, consolidation, or otherwise, the businesses
now owned and carried on by the following corporations organized and existing
under the Laws of the Commonwealth of Massachusetts:

                (a) Godfrey L. Cabot, Inc.

                (b) Cabot Carbon Company

                (c) Cabot Shops, Inc.

                (d) Cabot Gasoline Corporation

together with all their property, rights, privileges, powers and franchises;
and to assume in connection therewith all of the debts, liabilities and duties
of the said Massachusetts corporations.

        2.  To manufacture, produce, compound, refine, buy or otherwise
acquire, to sell or otherwise dispose of, and to deal in chemicals of every
description, chemical mixtures, medicines, pharmaceutical supplies, chemical
and medicinal preparations, drugs (except as forbidden by law), and any other
chemical products in the form of raw materials or otherwise, and by-products
derived from the manufacture thereof or made therefrom, carbon black, furnace
black, dye-stuffs, cements, minerals, superphosphates, soap, fertilizers,
paints, varnishes, pigments, polishes, stains, oils, acids, alcohols, coal,
coke, coal-tar, coal-tar products and derivatives, peat, peat products, rubber,
rubber goods, synthetic rubber, butadiene, and other petrochemicals of every
description, and all oher products related to any one or more of the foregoing.


                                      
                                      2
                                      


   5

        3.  To prospect, explore, drill for, produce and accumulate oil and
gas, liquified petroleum gas and natural gasoline; to buy, lease or otherwise
acquire, to sell, lease or otherwise dispose of, and to deal in oil, gas,
natural gasoline and any and all materials incidental to or necessary for the
production of oil, gas, natural gasoline, and all the by-products thereof, and
oil and gas rights, privileges and leases of all kinds and descriptions.

        4.  To mine, produce, manufacture, refine, handle, buy, or otherwise
acquire, and to sell or otherwise dispose of, and to deal in elements,
minerals, metals, ores, precious stones and base materials of every nature and
products using the same.

        5.  To buy, sell, manufacture, fabricate, produce and deal in steel,
iron, and other metals, metal products, and all other building materials; to
construct, maintain, work or operate, plants, mills, furnaces, factories,
engines, boilers, machinery and tools; and to carry on the business of
mechanical engineers and dealers in machinery and manufacturers of plants,
engines and other machinery, tool makers, brass founders, metal workers, boiler
makers, mill-wrights, machinists, iron and steel converters, smiths, builders,
carpenters, metallurgists, and electrical, civil, mechanical and water supply
engineers.

        6.  To conduct research, scientific or technical investigations and
experiments, development work and pilot plant work, and training and
educational programs, and to seek for and develop inventions, processes,
improvements, new or improved products, and uses for products, new or improved
manufacturing and operating techniques and methods, and wider scientific,
technical, manufacturing and operating knowledge, and to furnish, to this
corporation or to others, consulting, engineering, testing, experimental and
other services, all as may relate or be incidental to or be useful or
advantageous in or in connection with any business, operation or activity in
which this corporation is authorized to engage.



                                      3

   6



        7.  To manage and operate, in whole or in part, and to keep the books,
accounts and records, in whole or in part, of any other corporation, firm or
entity, and to enter into contracts for the performance of such service.

        8.  To carry on any manufacturing, selling, management, service,
research or other business, operation or activity which is lawful to be carried
on by a corporation organized under the General Corporation Law of the State of
Delaware as amended, whether or not similar or related or incidental to or
useful or advantageous in or in connection with the businesses, operations and
activities referred to in the foregoing paragraphs.

        9.  To manufacture, produce, purchase, lease or otherwise acquire, to
own, operate, and process, to sell, lease or otherwise dispose of, and to deal
in all kinds of machines, machinery, plant equipment, tools, materials,
merchandise, fixtures, goods and other property of all kinds useful in or in
connection with any business or activity in which this corporation is
authorized to engage.

        10.  To explore, prospect, buy, lease or otherwise acquire, to own,
hold and operate, to sell, lease or otherwise dispose of, and to deal in lands,
mining claims, water claims, water rights, mineral rights, and any other
rights, oil wells, gas wells, oil lands, gas lands and other real property, the
rights and interest in and to real property, manufacturing plants,
laboratories, pilot plants, oil refineries, gas works and plants, including
plants for the production of coke, gasoline, and other by-products, mines,
smelters, warehouses, offices and other buildings, structures, building
equipment, pipelines, railroads, and real estate improvements, all to the
extent permitted by law and as may relate or be incidental to or be useful in
or in connection with any business or activity in which this corporation is
authorized to engage.


                                       4

   7

        11.  To acquire, hold, use, sell, assign, lease, grant licenses under,
or otherwise dispose of, letters patent of the United States or any foreign
country, patent rights, licenses and privileges, inventions, improvements and
processes, copyrights, trademarks and trade names, relating to or useful in
connection with any business in which this corporation is authorized to engage.

        12.  To subscribe for, purchase or otherwise acquire, to hold and own,
to sell, assign, transfer or otherwise dispose of, and generally to deal in and
with, securities, and while the holder or owner thereof to have and exercise
all rights, powers and privileges of ownership, including the right to vote or
consent or give proxies or powers of attorney therefor; and to carry on any
business, operation or activity through a wholly or partly owned subsidiary.

        13.  To acquire by purchase, exchange, merger or consolidation or
otherwise all or any part of the property and assets, including the business,
good will, rights and franchises, of any corporation, association, trust, firm
or individual wherever organized, created or located, and in payment or
exchange therefor to pay cash, transfer property and issue securities to the
transferor or its security holders and to assume or become liable for any
liabilities and obligations; and to hold and operate or in any manner to
dispose of all or any part of the property and assets so acquired.

        14.  To dispose by sale, exchange, merger or consolidation or
otherwise, of all or any part of the property and assets, including the
business, good will, rights and franchises, of this corporation, to any
corporation, association, trust, firm or individual wherever organized, created
or located, for cash or property, including securities, or the assumption of
the liabilities and obligations of this corporation, and if desired, and
subject to the rights of creditors and preferred stockholders (if any), to
distribute such cash, securities or other property to the security holders of
this corporation in exchange for or in partial or complete liquidation or
redemption of their securities.

                                       5

   8

        15.  To enter into, make and perform contracts of every kind and
description with any person, firm, association, corporation, municipality,
county, state, body politic or government or colony or dependency thereof.

        16.  To have one or more offices and to carry on all or any of
operations and businesses in any and all parts of the world.

        17.  To borrow money and obtain credit; for money borrowed or for sale
or pledge or in order to pay, evidence or secure any liability or obligation,
to execute, issue and deliver and sell, pledge or otherwise dispose of bonds,
notes, debentures or other evidences of indebtedness, secured or unsecured; to
give security for any such bonds, notes, debentures or other evidences of
indebtedness or for any purchase price, guaranty, line of credit, covenant,
fidelity or performance bond or any other liability or obligation and any
premium interest and other sums due thereon or therewith and any covenants or
obligations connected therewith; and for the foregoing purposes to mortgage or
pledge or execute an indenture of mortgage or deed of trust upon or create a
lien upon or other security title or security interest in all or any part of
the property and assets, real and personal, of this corporation, then owned or
thereafter acquired.

        18.  To lend money, credit or security to, and to guarantee or assume
any liabilities and obligations of, and to aid in any other manner any
corporation, association, trust, firm or individual wherever organized, created
or located, any of whose securities are held by this corporation or in whose
affairs or prosperity this corporation has a lawful interest, and to do all
acts and things designed to protect, improve or enhance the value of such
securities or interest.

                                      6

   9

        19.  The directors of this corporation are authorized to make
charitable contributions as defined in the United States Internal Revenue Code,
as from time to time amended, in such amounts as the directors may determine to
be reasonable.

        20.  To do any and all acts and things in this Article Third set forth,
to the same extent as an individual might or could do, as principal, factor,
consignee, agent, contractor or otherwise, and either alone or in conjunction
or jointly with any corporation, association, trust, firm or individual; and,
in general, to do any and all acts and things and to engage in any and all
businesses whatsoever, necessary, suitable, advantageous or proper for or in
connection with or incidental to the exercise, transaction, promotion or
carrying on of any of the businesses, powers, purposes or objects in this
Article Third set forth; excepting in every case all acts, things and
businesses forbidden by law.

        21.  In this Article Third the word "securities" means, to the extent
that the context permits, stocks, shares, bonds, notes, debentures and other
evidences of interest in or indebtedness of any corporation, association, trust
or firm, and notes and other evidences or indebtedness of any individual, and
bonds, notes, debentures and other evidences of indebtedness of any country,
state, county, city, town or other governmental body or agency.

        22.  In this certificate of incorporation, unless it is otherwise
expressly provided, the statements of the businesses, objects and purposes of
this corporation shall be construed both as objects and powers, the enumeration
of specific powers shall not be held to limit or restrict in any manner the
exercise by this corporation of the general powers conferred upon corporations
by the laws of the State of Delaware, and no statement of any business, object
or purpose shall be deemed to limit or be exclusive of any other stated
business, object or purpose, but all are separate and cumulative and all may be
transacted, promoted and carried on separately or together and at any time and
from time to time.

                                       7
   10


        FOURTH:  The total number of shares of common stock which this
corporation shall have authority to issue is eighty million shares and the par
value of each of such shares is one dollar ($1.00) amounting in the aggregate
to Eighty Million Dollars ($80,000,000).

        The total number of shares of preferred stock which this corporation
shall have authority to issue is two million shares and the par value of each
of such shares is One Dollar ($1.00) amounting in the aggregate to Two Million
Dollars ($2,000,000).  The Board of Directors may provide for the issuance of
such preferred stock in one or more series, each series to have such voting
powers, full or limited, or no voting powers, such designations, preferences
and relative participating, optional or other special rights, and such
qualifications, limitations or retrictions thereof, and to be subject to such
terms of redemption, if any, as shall be specified by the Board of Directors
and stated and expressed in the vote or votes of the Board of Directors
providing for the issue of such preferred stock.

        The holders of the common stock shall be entitled to one vote for each
share of common stock registered in their respective names on the books of this
corporation.

        The board of directors may from time to time, in connection with any
employee stock option or purchase plan, fix limitations and restrictions on the
transfer of any or all of the authorized but unissued shares of this
corporation made available for such stock option or purchase plan, such
restrictions to take effect upon the issue of such shares.  No such limitation
or restriction shall be valid unless notice thereof is given on the certificate
or certificates representing such shares.


                                       8
   11


        No stockholder of this corporation shall by reason of his holding
shares of any class have any pre-emptive or preferential purchase or subscribe
to any shares of any class of this corporation, now or hereafter to be
authorized, or any notes, debentures, bonds, or other securities convertible
into or carrying options or warrants to purchase shares of any class, now or
hereafter to be authorized, whether or not the issue of any such shares, or such
notes, debentures, bonds or other securities would adversely affect the dividend
or voting rights of such stockholder, other than such rights, if any, as the
board of directors, in its discretion from time to time may grant, and at such
price as the board of directors in its discretion may fix; and the board of
directors may issue shares of any class of this corporation, or any notes,
debentures, bonds, or other securities convertible into or carrying options or
warrants to purchase shares of any class, without offering any such shares or
securities, either in whole or in part, to the existing stockholders of any
class.

        FIFTH:  The minimum amount of capital with which the corporation will
commence business is One Thousand Dollars ($1,000.00).

        The board of directors, without the assent of or other action by the
stockholders, may from time to time authorize the issue and sale of shares of
stock of this corporation now or hereafter authorized, for such consideration
and upon such terms as the board of directors may determine, or the board of
directors may authorize such consideration and terms to be fixed in whole or in
part by any officer or officers of this corporation.

        SIXTH:  This corporation is to have perpetual existence.

        SEVENTH:  The private property of the stockholders shall not be subject
to the payment of corporate debts to any extent whatever.


                                       9

   12

        EIGHTH:  The following provisions are inserted for the regulation and
conduct of the affairs of this corporation, and it is expressly provided that
they are intended to be in furtherance and not in limitation or exclusion of
the powers elsewhere conferred herein or in the by-laws or conferred by law:

        (a)  Except as may be otherwise expressly required by law or by other
    provisions of this certificate of incorporation or by the by-laws, the
    board of directors shall have and may exercise, transact, manage, promote
    and carry on all of the powers, authorities, businesses, objects and
    purposes of this corporation.

        (b)  The directors who are not directors emeritus shall be divided into
    three classes of approximately equal size.  At the annual meeting to be
    held January 21, 1969, one class shall be elected to a term of three years,
    another class to a term of two years, and the third class to a term of one
    year; and at each subsequent annual election the successors to directors
    whose terms shall expire that year shall each be elected to a term of three
    years.  The directors emeritus, if any, shall be elected or appointed for
    such terms and shall have such duties not contrary to law as may from time
    to time be provided for in the by-laws.  No director need be a stockholder. 
    The election of directors need not be by ballot unless the by-laws shall so
    require.

        (c)  By-laws may be made, altered, amended or repealed by a vote of the
    stockholders or a vote of the majority of the directors then in office at
    any annual, regular, or special stockholders or directors meeting, called
    for that purpose, the notice of which shall specify the subject matter of
    the proposed new by-law or the alteration, amendment, or repeal of an
    existing by-law, or the articles to be affected thereby.  Any



                                       10

   13

    by-law whether made, altered, amended, or repealed by the stockholders or
    directors may be repealed, amended, further amended, or reinstated, as the
    case may be, by either the  stockholders or the directors as aforesaid.

        (d)  The board of directors may at any time set apart out of any of the
    funds of this corporation available for dividends a reserve or reserves for
    any proper purpose and may at any time reduce or abolish any such reserve. 
    Any other proper reserves may also be carried.

        (e)  This corporation may purchase, hold, sell and transfer shares of
    its own capital stock, but shall not use its funds or property for the
    purchase of its own shares of capital stock when such use would cause any
    impairment of the capital of this corporation, subject always to the right
    of this corporation to reduce its capital or to redeem any preferred or
    special shares out of capital as permitted by law.  Shares of its own
    capital stock belonging to this corporation shall not be voted upon
    directly or indirectly.

        (f)  The board of directors may from time to time authorize and
    maintain bonus, profit sharing or other types of incentive or compensation
    plans or pension or retirement plans for the employees (including officers
    and directors) of this corporation or of its subsidiaries, affiliates or
    any other corporation, association, trust or firm wherever organized,
    created or located in whose affairs or prosperity this corporation has any
    lawful interest and fix the amount of the profits to be distributed or
    shared and determine the persons to participate in any such plans and the
    amounts of their respective participation or benefits.


                                       11

   14

        (g)  The board of directors may from time to time determine whether and
    to what extent and at what times and places and under what conditions and
    regulations the accounts and books and papers of this corporation, or any
    of them, shall be open to the inspection of the stockholders, and no
    stockholder shall have any right to inspect any account, book or document
    of this corporation, except as and to the extent expressly provided by law
    with reference to the right of stockholders to examine the original or
    duplicate stock ledger, or otherwise expressly provided by law, or except
    as expressly authorized by resolution of the board of directors.

        (h)  The directors of this corporation are likely to be connected with
    other corporations, partnerships, associations or firms with which from
    time to time this corporation may have business dealings.  No contract or
    other transaction between this corporation and any other corporation,
    partnership, association or firm and no act of this corporation shall be
    affected by the fact that directors of this corporation are pecuniarily or
    otherwise interested in, or are directors, members, or officers of such
    other corporation, partnership, association or firm.  Any director
    individually, or any firm of which such director may be a member, may be a
    party to or may be pecuniarily or otherwise interested in any contract or
    transaction of this corporation, provided that the fact that he or such
    firm is so interested shall be disclosed or shall have been known to the
    board of directors or a majority thereof. Every contract, act or
    transaction which at any annual meeting of the stockholders, or at any
    special meeting of the stockholders called for the purpose, among others,
    of considering such contract, act or transaction, shall be authorized,
    approved or ratified by vote of the holders of a majority of the shares of
    the capital stock of this corporation present in person or represented by
    proxy at such meeting



                                       12

   15

    (provided that a quorum of stockholders be there present or represented by
    proxy) shall be as valid and binding upon this corporation and upon all its
    stockholders as though such a contract, act or transaction had been
    expressly authorized, approved and ratified by every stockholder of this
    corporation.

                (i)  No person shall be liable to this corporation for any loss
    or damage suffered by it on account of any action taken or omitted to be
    taken by him in good faith as a director, member of a directors' committee
    or officer of this corporation, if such person exercised or used the same
    degree of care and skill as a prudent man would have exercised or used
    under the circumstances in the conduct of his own affairs.  Without
    limitation of the foregoing, any such person shall be deemed to have
    exercised or used such degree of care and skill if he took or omitted to
    take such action in reliance in good faith upon advice of counsel for this
    corporation, or the books of account or other records of this corporation,
    or reports or information made or furnished to this corporation by any
    official, accountant, engineer, agent, or employee of this corporation, or
    by any independent public accountant or auditor, counsel, engineer,
    appraiser or other expert retained or employed by this corporation and
    selected with reasonable care by the board of directors, by any such
    committee or by any authorized officer of this corporation.

        (j)  The Company shall indemnify any person who was or is party or is
    threatened to be made a party to any threatened, pending or completed
    action, suit or proceeding, whether civil, criminal, administrative or
    investigative (and whether or not by or in the right of the corporation) by
    reason of the fact that he is or was a director, officer, employee or agent
    of the Company, or is or was serving at the request of the Company as a
    director, officer, employee or agent of another company,


                                       13

   16

    partnership, joint venture, trust or other enterprise, against expenses
    (including attorneys' fees), judgments, fines and amounts paid in
    settlement actually and reasonably incurred by him in connection with such
    action, suit or proceeding, to the extent and under the circumstances
    permitted by the General Corporation Law of The State of Delaware as
    amended from time to time.  Such indemnification (unless ordered by a
    court) shall be made as authorized in a specific case upon a determination
    that indemnification of the director, officer, employee or agent is
    proper in the circumstances because he has met the applicable standards of
    conduct set forth in the General Corporation Law of the State of Delaware. 
    Such determination shall be made (1) by the Board of Directors by a
    majority vote of a quorum consisting of directors who were not parties to
    such action, suit or proceeding, or (2) if such quorum is not obtainable,
    or even if obtainable a quorum of disinterested directors so directs, by
    independent legal counsel in a written opinion, or (3) by the stockholders. 
    The foregoing right of indemnification shall not be deemed exclusive of any
    other rights to which those seeking indemnification may be entitled under
    any by-law, agreement, vote of stockholders or disinterested directors or
    otherwise, and shall continue as to a person who has ceased to be a
    director, officer, employee or agent and shall inure to the benefit of the
    heirs, executors and administrators of such a person.

        NINTH:  Whenever a compromise or arrangement is proposed between this
corporation and its creditors or any class of them and/or between this
corporation and its stockholders or any class of them, any court of equitable
jurisdiction within the State of Delaware may, on the application in a summary
way of this corporation or of any creditor or stockholder thereof, or on the
application of any receiver or receivers appointed for this corporation under
the provisions of section 291 of Title 8 of the Delaware Code or on the


                                       14
   17


application of trustees in dissolution or of any receiver or receivers
appointed for this corporation under the provisions of section 279 of Title 8
of the Delaware Code order a meeting of the creditors or class of creditors,
and/or of the stockholders or class of stockholders of this corporation, as the
case may be, to be summoned in such manner as the said court directs.  If
a majority in number representing three-fourths in value of the creditors or
class of creditors, and/or of the stockholders or class of stockholders of this
corporation, as the case may be, agree to any compromise or arrangement and to
any reorganization of this corporation as consequence of such compromise or
arrangement, the said compromise or arrangement and the said reorganization
shall, if sanctioned by the court to which the said application has been made,
be binding on all of the creditors or class of creditors, and/or on all the
stockholders or class of stockholders of this corporation, as the case may be,
and also on this corporation.

        TENTH:  This corporation reserves the right to amend, alter, change or
repeal any provision contained in this certificate of incorporation, in the
manner now or hereafter prescribed by statute, and all rights conferred upon
stockholders herein are granted subject to this reservation.

        ELEVENTH:  The directors may be paid their expenses, if any, of
attendance at each meeting of the board of directors and may be paid a fixed
sum for attendance at each meeting of the board of directors or a stated salary
as director.  No such payment shall preclude any director from serving this
corporation in any other capacity and receiving compensation therefor.  Members
of special or standing committees may be allowed like compensation for
attending committee meetings.




                                       15

   18



        This Restated Certificate of Incorporation restates and integrates the
corporation's Certificate of Incorporation as heretofore amended by
Certificates of Amendment as filed with the Secretary of State of the State of
Delaware on May 7, 1968, January 21, 1969, March 8, 1971, February 21, 1978 and
October 8, 1980, and eliminates certain provisions that under the General
Corporation Law of Delaware are no longer required to be included in the
Certificate of Incorporation.  Except for such provisions so eliminated, this
Restated Certificate of Incorporation does not further amend the corporation's
Certificate of Incorporation as heretofore amended and no discrepancy exists
between those provisions and the provisions of this Restated Certificate of
Incorporation.

        IN WITNESS WHEREOF,  CABOT CORPORATION has caused this Restated
Certificate of Incorporation to be duly executed this 14th day of October, 1983
by Robert A. Charpie, its President, and attested by Walter F. Greeley, its
Secretary.

                                                CABOT CORPORATION


                                                By: /S/ ROBERT A. CHARPIE
                                                   ----------------------------
ATTEST:                                            Robert A. Charpie, President


By /S/ WALTER F. GREELEY
   -----------------------------
   Walter F. Greeley, Secretary


                                       16


   19

                            CERTIFICATE OF SECRETARY

        The undersigned, Waiter F. Greeley, hereby certifies that he is the
duly elected, Qualified and acting Secretary of CABOT CORPORATION, a
corporation organized and existing under the laws of the State of Delaware, and
that the foregoing 16 numbered pages are a true, correct and complete copy of
the Restated Certificate of Incorporation of said Corporation.

        IN WITNESS WHEREOF, I have hereunto set my hand and impressed the
corporate seal of CABOT CORPORATION on this 14th day of October, 1983.




/S/ WALTER F. GREELEY
- --------------------------
                 Secretary                               [ Corporate Seal ]
 






                                       17


   20
                                                               Exhibit 3(a)

                            CERTIFICATE OF AMENDMENT
                            ------------------------

                                       OF
                                       --

                     RESTATED CERTIFICATE OF INCORPORATION
                     -------------------------------------


       CABOT CORPORATION, a corporation organized and existing under
and by virtue of the General Corporation Law of the State of
Delaware,

DOES HEREBY CERTIFY:

      FIRST: That the Board of Directors of said Corporation, by
unanimous written consent and agreement in lieu of a formal meeting,
dated as of November 21, 1984, adopted a vote setting forth the
proposed amendment to the Restated Certificate of Incorporation of
said Corporation, declaring said amendment to be advisable and
recommending the adoption of said amendment by vote of the
stockholders of the Corporation at its Annual Meeting of
Stockholders called for February 8, 1985. The vote setting forth
the proposed amendment is as follows:

VOTED: That the Restated Certificate of Incorporation of this Corporation
be amended, subject to stockholder approval, as follows:

1. by renumbering the present Articles "TENTH" and "ELEVENTH" as
   "ELEVENTH" and "TWELFTH".

2. by adding the following language at the end of newly numbered Article
   ELEVENTH:

       "Notwithstanding any provision of law, this restated
       certificate of incorporation or the by-laws of this corporation
       (and notwithstanding the fact that a lesser percentage may be
       specified by law, this restated certificate of incorporation or
       the by-laws of this corporation), and in addition to any
       affirmative vote of the holders of any class of preferred stock of
       this corporation outstanding or any other class of capital stock
       of this corporation or any series of any of the foregoing then
       outstanding which is required by law or by or pursuant to this

   21

      restated certificate of incorporation, the affirmative vote of the
      holders of 66-2/3 percent or more of the voting power of the
      shares of the then outstanding shares of stock of all classes and
      series of this corporation entitled to vote generally in the
      election of directors, voting together as a single class, shall be
      required to alter, amend or repeal paragraph (a), (b) or (c) of
      Article EIGHTH or Article TENTH of this restated certificate of
      incorporation or to adopt any provision inconsistent therewith."

3. by adding a new Article TENTH as follows:

      "TENTH: 1. Vote Required for Certain Business Combinations.

          In addition to any affirmative vote required by law or this
   restated certificate of incorporation, and except as otherwise
   expressly provided in section 2 of this Article TENTH:

             (a) Any merger or consolidation of this corporation or any
      subsidiary (as hereinafter defined) with (1) any interested
      stockholder (as hereinafter defined) or (2) any other corporation
      or other person (whether or not itself an interested stockholder)
      which is, or after such merger or consolidation would be, an
      affiliate (as hereinafter defined) of an interested stockholder; or

             (b) Any plan of exchange for all outstanding shares of this
      corporation or any subsidiary or for any class of shares of either
      with (1) any interested stockholder or (2) any other corporation
      or other person (whether or not itself an interested stockholder)
      which is, or after such plan of exchange would be, an affiliate of
      an interested stockholder; or

   22

          (c) Any sale, lease, exchange, mortgage, pledge, transfer or
   other disposition (in one transaction or a series of transactions)
   to or with any interested stockholder or any affiliate of any
   interested stockholder of any assets of this corporation or any
   subsidiary having an aggregate fair market value (as hereinafter
   defined) of $20,000,000 or more; or

          (d) The issuance or transfer by this corporation or any
   subsidiary (in one transaction or a series of transactions) of any
   securities of this corporation or any subsidiary to any interested
   stockholder or any affiliate of any interested stockholder in
   exchange for cash, securities or other property (or a combination
   thereof) having an aggregate fair market value of $20,000,000 or
   more; or

          (e) The adoption of any plan or proposal for the liquidation
   or dissolution of this corporation proposed by or on behalf of an
   interested stockholder or any affiliate of any interested
   stockholder; or

          (f) Any reclassification of securities (including any reverse
   stock split), or recapitalization of this corporation, or any
   merger or consolidation of this corporation with any of its
   subsidiaries or any other transaction (whether or not with or into
   or otherwise involving an interested stockholder) which has the
   effect, directly or indirectly, of increasing the proportionate
   share of the outstanding shares of any class of stock or
   securities convertible into stock of this corporation or any
   subsidiary which is directly or indirectly owned by any interested
   stockholder or any affiliate of any interested stockholder;

shall require the affirmative vote of the holders of at least 66 2/3
percent of the combined voting power of the then outstanding shares of

   23

 stock of all classes and series of this corporation entitled to vote
 generally in the election of directors (the "voting stock"), in each
 case voting together as a single class. Such affirmative vote shall
 be required notwithstanding the fact that no vote may be required, or
 that a lesser percentage may be specified, by law or by this restated
 certificate of incorporation or any vote or votes adopted pursuant to
 Article THIRD of this restated certificate of incorporation or in any
 agreement with any national securities exchange or otherwise.

        2. When Higher Vote is not Required. The provisions of this
 Article TENTH shall not be applicable to any particular business
 combination (as hereinafter defined), and such business combination
 shall require only such affirmative vote as is required by law, any
 other provision of this restated certificate of incorporation, any
 preferred stock designation or any agreement with any national
 securities exchange, if, all of the conditions specified in either of
 the following paragraphs (a) and (b) are met:

        (a) Approval by Continuing Directors. The business combination
 shall have been approved by a majority of the continuing directors (as
hereinafter defined), it being understood that this condition shall
not be capable of satisfaction unless there is at least one continuing
director; or

        (b) Price and Procedure Requirements. All of the following
 conditions shall have been met:

           (1) The aggregate amount of the cash and the fair market
    value as of the date of the consummation of the business
    combination of any consideration other than cash to be received
    per share by holders of common stock (as hereinafter defined) in
    such business combination shall be at least equal to the highest
    of the following:

   24

   (A) (if applicable) the highest per share price (including
   any brokerage commissions, transfer taxes and soliciting
   dealers' fees) paid by the interested stockholder for any
   shares of common stock acquired by it (i) within the two-year
   period immediately prior to the first public announcement of
   the proposal of the business combination (the "announcement
   date") or (ii) in the transaction in which it became an
   interested stockholder, whichever is higher; or

   (B) the fair market value per share of common stock on the
   announcement date or on the date on which the interested
   stockholder became an interested stockholder (such latter date
   is referred to in this Article TENTH as the "determination
   date"), whichever is higher; or

   (C) (if applicable) the price per share equal to the fair
   market value per share of common stock determined pursuant to
   paragraph (b)(1)(B) above, multiplied by the ratio of (i) the
   highest per share price (including any brokerage commissions,
   transfer taxes and soliciting dealers' fees) paid by the
   interested stockholder for any shares of common stock acquired
   by it within the two-year period immediately prior to the
   announcement date to (ii) the fair market value per share of
   common stock on the first day in such two-year period upon
   which the interested stockholder acquired any shares of common
   stock; and

       (2) The consideration to be received by holders of a
particular class or series of outstanding voting stock (including
common stock) shall be in cash or in the same form as the
interested stockholder has previously paid for shares of such
class. If the interested stockholder has paid for shares of
voting stock with varying forms of consideration, the form of

   25

consideration to be received by holders of such class or series of
voting stock shall be either cash or the form used to acquire
beneficially the largest number of shares of such class or series
of voting stock previously acquired by it; and

       (3) After such interested stockholder has become an
interested stockholder and prior to the consummation of such
business combination:

              (A) except as approved by a majority of the continuing
directors, there shall have been no failure to declare and pay at
the regular date therefor any full quarterly dividends (whether or
not cumulative) on any outstanding preferred stock;

              (B) there shall have been (i) no reduction in the annual
rate of dividends paid on the common stock (except as necessary to
reflect any subdivision of the common stock), except as approved
by a majority of the continuing directors, and (ii) an increase in
such annual rate of dividends as necessary to reflect any
reclassification (including any reverse stock split),
recapitalization, reorganization or any similar transaction which
has the effect of reducing the number of outstanding shares of the
common stock, unless the failure so to increase such annual rate
is approved by a majority of the continuing directors; and

              (C) such interested stockholder shall not have become the
beneficial owner of any additional shares of voting stock except
as part of the transaction in which it became an interested
stockholder; and

       (4) After such interested stockholder has become an
interested stockholder, such interested stockholder shall not have
received the benefit, directly or indirectly (except
proportionately as a stockholder), of any loans, advances,

   26

guarantees, pledges or other financial assistance or any tax
credits or other tax advantages provided by the corporation,
whether in anticipation of or in connection with such business
combination or otherwise; and

       (5) A proxy or information statement describing the proposed
business combination and complying with the requirements of the
Securities Exchange Act of 1934 (the "1934 Act") and the rules and
regulations thereunder (or any subsequent provisions replacing
such 1934 Act, rules or regulations) shall be mailed to public
stockholders of the corporation at least 30 days prior to the
consummation of such business combination (whether or not such
proxy or information statement is required to be mailed pursuant
to the 1934 Act or subsequent provisions).

3. Certain Definitions. For the purposes of this Article TENTH:

       (a) "affiliate" or "associate" has the respective meanings
ascribed to such terms in Rule 12b-2 of the General Rules and
Regulations under the 1934 Act, as in effect on February 8, 1985.

       (b) "board" means the board of directors of this corporation.

       (c) A person is a "beneficial owner" of any voting stock:

         (1) which such person or any of its affiliates or
       associates beneficially owns, directly or indirectly; or

         (2) which such person or any of its affiliates or
       associates has (A) the right to acquire (whether such right is
       exercisable immediately or only after the passage of time),
       pursuant to any agreement, arrangement or understanding or
       upon the exercise of conversion rights, exchange rights,
       warrants or options, or otherwise, or (B) the right to vote or
       direct the vote pursuant to any agreement, arrangement or
       understanding; or

   27

        (3) which are beneficially owned, directly or indirectly,
   by any other person with which such person or any of its
   affiliates or associates has any agreement, arrangement or
   understanding for the purpose of acquiring, holding, voting or
   disposing of any shares of voting stock.

       (d) The term "business combination" means any transaction
which is referred to in any one or more of paragraphs (a) through
(f) of Section 1.

       (e) "common stock" means the common capital stock of this
corporation.

       (f) "continuing director" means any member of the board who
is unaffiliated with and not a nominee of the interested
stockholder and was a member of the board prior to the time that
the interested stockholder became an interested stockholder, and
any successor of a continuing director who is unaffiliated with,
and not a nominee of the interested stockholder and who is
recommended to succeed a continuing director by a majority of
continuing directors then on the board.

        (g) "fair market value" means: (1) in the case of stock, the
 highest closing sale price during the 30-day period immediately
 preceding the date in question of a share of such stock on the
 Composite Tape for New York Stock Exchange-Listed Stocks, or, if
 such stock is not quoted on the Composite Tape, on the New York
 Stock Exchange, or, if such stock is not listed on such Exchange,
 on the principal United States securities exchange registered
 under the 1934 Act on which such stock is listed, or, if such
 stock is not listed on any such exchange, the highest closing
 price or bid quotation with respect to a share of such stock
 during the 30-day period preceding the date in question on the

   28

National Association of Securities Dealers, Inc. Automated
Quotations System or any system then in use, or if no such
quotations are available, the fair market value on the date in
question of a share of such stock as determined by a majority of
the continuing directors in good faith; and (2) in the case of
stock that is not traded on any United States registered
securities exchange nor in any over-the-counter market or in the
case of property other than cash or stock, the fair market value
of such property on the date in question as determined by a
majority of the continuing directors in good faith.

       (h) "interested stockholder" means any person (other than
this corporation or any subsidiary) who or which:

          (1) is the beneficial owner, directly or indirectly, of
   more than 10 percent of the combined voting power of the then
   outstanding voting stock; or

          (2) is an affiliate of the corporation and at any time
   within the two-year period immediately prior to the date in
   question was the beneficial owner, directly or indirectly, of
   10 percent or more of the voting power of the then outstanding
   voting stock; or

          (3) is an assignee of or has otherwise succeeded to the
   beneficial ownership of any shares of voting stock which were
   at any time within the two-year period immediately prior to
   the date in question beneficially owned by any interested
   stockholder, if such assignment or succession shall have
   occurred in the course of a transaction or series of
   transactions not involving a public offering within the
   meaning of the Securities Act of 1933.

   29

          For the purpose of determining whether a person is an
   interested stockholder pursuant to this paragraph (h) of this
   Section 3, the number of shares of voting stock deemed to be
   outstanding shall include shares deemed owned through application
   of paragraph (c) of this section 3 but shall not include any other
   shares of voting stock which may be issuable pursuant to any
   agreement, arrangement or understanding, or upon exercise of
   conversion rights, warrants or options, or otherwise.

          (i) A "person" means any individual, firm, corporation, group
   (as such term is used in Rule 13d of the General Rules and
   Regulations under the 1934 Act as in effect on February 8, 1985)
   or other entity.

          (j) "subsidiary" means any corporation of which a majority of
   any class of equity security is owned, directly or indirectly, by
   this corporation; provided, however, that for the purposes of the
   definition of interested stockholder set forth in paragraph (h) of
   this section 3, the term "subsidiary" means only a corporation of
   which a majority of each class of equity security is owned,
   directly or indirectly, by this corporation.

       4. Powers of the Board. A majority of the continuing directors
shall have the power and duty to determine for the purposes of this
Article TENTH, on the basis of information known to them after
reasonable inquiry, all facts necessary to determine compliance with
this Article TENTH, including without limitation, (a) whether a person
is an interested stockholder; (b) the number of shares of voting stock
beneficially owned by any person; (c) whether a person is an affiliate
or associate of another person; (d) whether the requirements of
section 2.(b) of this Article TENTH have been met with respect to any
proposed business combination, and (e) whether the assets which are
the subject of any business combination have, or the consideration to

   30

   be received for the issuance or transfer of securities by this
   corporation or any subsidiary in any business combination has, an
   aggregate fair market value of $20,000,000 or more. Any such
   determination made in good faith shall be binding and conclusive for
   all purposes of this Article TENTH.

          5. No Effect on Fiduciary Obligations of Interested
   Stockholders. Nothing contained in this Article TENTH shall be
   construed to relieve any interested stockholder from any fiduciary
   obligation imposed by law."

       SECOND: That thereafter, pursuant to vote of its Board of Directors,
the Annual Meeting of Stockholders of said Corporation was duly called
and held, upon notice in accordance with Section 222 of the General
Corporation Law of the State of Delaware, at which meeting the necessary
number of shares as required by statute were voted in favor of the
amendment.

       THIRD: That said amendments were duly adopted in accordance with the
applicable provision of Section 242 of the General Corporation Law of the
State of Delaware.

      FOURTH: That the capital of said Corporation shall not be reduced
under or by reason of said amendment.

       IN WITNESS WHEREOF, said CABOT CORPORATION has caused this
certificate to be signed by Robert A. Charpie, its President, and
attested by Henley R. Webb, its Assistant Secretary this 11th day of
February, 1985.

ATTEST:                                CABOT CORPORATION
                                      
/s/ Henley R. Webb                     By /s/ Robert A. Charpie
- ----------------------                    ----------------------
Assistant Secretary                       President
   31

                                                               EXHIBIT 3(a)

                  CERTIFICATE OF DESIGNATION, PREFERENCES AND
            RIGHTS OF SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                       of

                               CABOT CORPORATION

             Pursuant to Section 151 of the General Corporation Law
                            of the State of Delaware

        We, Robert A. Charpie, President, and Walter F. Greeley, Secretary, of
Cabot Corporation, a corporation organized and existing under the General
Corporation Law of the State of Delaware, in accordance with the provisions
of Section 103 thereof, DO HEREBY CERTIFY:

        That pursuant to the authority conferred upon the Board of Directors by
the Restated Certificate of Incorporation, as amended, of the said Corporation,
the said Board of Directors on November 14, 1986, adopted the following
resolution creating a series of 800,000 shares of Preferred Stock designated as
Series A Junior Participating Preferred Stock:

        VOTED, that pursuant to the authority vested in the Board of Directors
of this Corporation in accordance with the provisions of its Restated
Certificate of Incorporation, as amended, a series of Preferred Stock of the
Corporation be and it hereby is created, and that the designation and amount
thereof and the voting powers, preferences and relative, participating,
optional and other special rights of the shares of such series, and the
qualifications, limitations or restrictions thereof are as follows:

        Section 1. DESIGNATION AND AMOUNT. The shares of such series shall be
designated as "Series A Junior Participating Preferred Stock" and the number of
shares constituting such series shall be 800,000.

        Section 2. DIVIDENDS AND DISTRIBUTIONS.

        (A) Subject to the prior and superior rights of the holders of any
shares of any series of Preferred Stock ranking prior and superior to the
shares of Series A Junior Participating Preferred Stock with respect to
dividends, the holders of shares of Series A Junior Participating Preferred
Stock shall be entitled to receive, when, as and if declared by the Board of
Directors out of
   32

funds legally available for the purpose, quarterly dividends payable in cash
on the eleventh day of January, March, June and September in each year (each
such date being referred to herein as a "Quarterly Dividend Payment Date"),
commencing on the first Quarterly Dividend Payment Date after the first
issuance of a share or fraction of a share of Series A Junior Participating
Preferred Stock, in an amount per share (rounded to the nearest cent) equal to
the greater of (a) $25 or (b) subject to the provision for adjustment
hereinafter set forth, 100 times the aggregate per share amount of all cash
dividends, and 100 times the aggregate per share amount (payable in kind)
of all non-cash dividends or other distributions other than a dividend
payable in shares of Common Stock or a subdivision of the outstanding shares of
Common Stock (by reclassification or otherwise), declared (but not withdrawn)
on the common stock, par value $1.00 per share, of the Corporation (the "Common
Stock") since the immediately preceding Quarterly Dividend Payment Date, or,
with respect to the first Quarterly Dividend Payment Date, since the first
issuance of any share or fraction of a share of Series A Junior Participating
Preferred Stock. In the event the Corporation shall at any time after November
14, 1986 (the "Rights Declaration Date") (i) declare any dividend on Common
Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common
Stock, or (iii) combine the outstanding Common Stock into a smaller number of
shares, then in each such case the amount to which holders of shares of Series
A Junior Participating Preferred Stock were entitled immediately prior to
such event under clause (b) of the preceding sentence shall be adjusted by
multiplying such amount by a fraction the numerator of which is the number of
shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

        (B) The Corporation shall declare a dividend or distribution on the
Series A Junior Participating Preferred Stock as provided in paragraph (A)
above immediately after it declares a dividend or distribution on the Common
Stock (other than a dividend payable in shares of Common Stock); provided that,
in the event no dividend or distribution shall have been declared on the Common
Stock during the period between any Quarterly Dividend Payment Date and the
next subsequent Quarterly Dividend Payment Date, a dividend of $25 per share on
the Series A

                                       2
   33

Junior Participating Preferred Stock shall nevertheless be payable on such
subsequent Quarterly Dividend Payment Date.

        (C) Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Junior Participating Preferred Stock from the Quarterly
Dividend Payment Date next preceding the date of issue of such shares of Series
A Junior Participating Preferred Stock, unless the date of issue of such shares
is prior to the record date for the first Quarterly Dividend Payment Date, in
which case dividends on such shares shall begin to accrue from the date of
issue of such shares, or unless the date of issue is a Quarterly Dividend
Payment Date or is a date after the record date for the determination of
holders of shares of Series A Junior Participating Preferred Stock entitled
to receive a quarterly dividend and before such Quarterly Dividend Payment
Date, in either of which events such dividends shall begin to accrue and be
cumulative from such Quarterly Dividend Payment Date. Accrued but unpaid
dividends shall not bear interest. Dividends paid on the shares of Series A
Junior Participating Preferred Stock in an amount less than the total amount of
such dividends at the time accrued and payable on such shares shall be
allocated pro rata on a share-by-share basis among all such shares at the time
outstanding. The Board of Directors may fix a record date for the determination
of holders of shares of Series A Junior Participating Preferred Stock entitled
to receive payment of a dividend or distribution declared thereon, which record
date shall be no more than 30 days prior to the date fixed for the payment
thereof.

        Section 3. VOTING RIGHTS. The holders of shares of Series A Junior
Participating Preferred Stock shall have the following voting rights:

        (A) Subject to the provision for adjustment hereinafter set forth, each
share of Series A Junior Participating Preferred Stock shall entitle the holder
thereof to 100 votes on all matters submitted to a vote of the stockholders of
the Corporation. In the event the Corporation shall at any time after the
Rights Declaration Date (i) declare any dividend on Common Stock payable in
shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii)
combine the outstanding Common Stock into a smaller number of shares, then in
each such case the number of votes per share to which

                                       3
   34

holders of shares of Series A Junior Participating Preferred Stock were
entitled immediately prior to such event shall be adjusted by multiplying such
number by a fraction the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event.

        (B) Except as otherwise provided herein, by the Restated Certificate of
Incorporation, as amended, or by law, the holders of shares of Series A Junior
Participating Preferred Stock and the holders of shares of Common Stock
shall vote together as one class on all matters submitted to a vote of
stockholders of the Corporation.

        (C) (i) If at any time dividends on any Series A Junior Participating
Preferred Stock shall be in arrears in an amount equal to six (6) quarterly
dividends thereon, the occurrence of such contingency shall mark the beginning
of a period (herein called a "default period") which shall extend until such
time when all accrued and unpaid dividends for all previous quarterly dividend
periods and for the current quarterly dividend period on all shares of Series A
Junior Participating Preferred Stock then outstanding shall have been declared
and paid or set apart for payment. During each default period, all holders of
Preferred Stock (including holders of the Series A Junior Participating
Preferred Stock) with dividends in arrears in an amount equal to six (6)
quarterly dividends thereon, voting as a class, irrespective of series, shall
have the right to elect two (2) Directors.

        (ii) During any default period, such voting right of the holders of
Series A Junior Participating Preferred Stock may be exercised initially at a
special meeting called pursuant to subparagraph (iii) of this Section 3(C) or
at any annual meeting of stockholders, and thereafter at annual meetings of
stockholders, provided that neither such voting right nor the right of the
holders of any other series of Preferred Stock, if any, to increase, in certain
cases, the authorized number of Directors shall be exercised unless the holders
of one-third in number of shares of Preferred Stock outstanding shall be
present in person or by proxy. The absence of a quorum of the holders of Common
Stock shall not affect the exercise by the holders of Preferred Stock of such
voting right. At any meeting at which the holders of

                                       4
   35
Preferred Stock shall exercise such voting right initially during an existing
default period, they shall have the right, voting as a class, to elect
Directors to fill such vacancies, if any, in the Board of Directors as may then
exist up to two (2) Directors or, if such right is exercised at an annual
meeting, to elect two (2) Directors. If the number which may be so elected at
any special meeting does not amount to the required number, the holders of
the Preferred Stock shall have the right to make such increase in the number of
Directors as shall be necessary to permit the election by them of the required
number. After the holders of the Preferred Stock shall have exercised their
right to elect Directors in any default period and during the continuance of
such period, the number of Directors shall not be increased or decreased
except by vote of the holders of Preferred Stock as herein provided or pursuant
to the rights of any equity securities ranking senior to or PARI PASSU with
the Series A Junior Participating Preferred Stock.

        (iii) Unless the holders of Preferred Stock shall, during an existing
default period, have previously exercised their right to elect Directors, the
Board of Directors may order, or any stockholder or stockholders owning in the
aggregate not less than ten percent (10%) of the total number of shares of
Preferred Stock outstanding, irrespective of series, may request, the calling of
a special meeting of the holders of Preferred Stock, which meeting shall
thereupon be called by the President, a Vice-President or the Secretary of the
Corporation. Notice of such meeting and of any annual meeting at which holders
of Preferred Stock are entitled to vote pursuant to this paragraph (C) (iii)
shall be given to each holder of record of Preferred Stock by mailing a copy of
such notice to him at his last address as the same appears on the books of the
Corporation. Such meeting shall be called for a time not earlier than 20 days
and not later than 60 days after such order or request or in default of the
calling of such meeting within 60 days after such order or request, such meeting
may be called on similar notice by any stockholder or stockholders owning in the
aggregate not less than ten percent (10%) of the total number of shares of
Preferred Stock outstanding. Notwithstanding the provisions of this paragraph
(C)(iii), no such special meeting shall be called during the period within 60
days immediately preceding the date fixed for the next annual meeting of the
stockholders.

                                       5
   36
        (iv) In any default period, the holders of Common Stock, and other
classes of stock of the Corporation if applicable, shall continue to be
entitled to elect the whole number of Directors until the holders of Preferred
Stock shall have exercised their right to elect two (2) Directors voting as a
class, after the exercise of which right (x) the Directors so elected by the
holders of Preferred Stock shall continue in office until their successors
shall have been elected by such holders or until the expiration of the default
period, and (y) any vacancy in the Board of Directors may (except as provided
in paragraph (C)(ii) of this Section 3) be filled by vote of a majority of the
remaining Directors theretofore elected by the holders of the class of stock
which elected the Director whose office shall have become vacant. References in
this paragraph (C) to Directors elected by the holders of a particular class of
stock shall include Directors elected by such Directors to fill vacancies as
provided in clause (y) of the foregoing sentence.

        (v) Immediately upon the expiration of a default period, (x) the right
of the holders of Preferred Stock as a class to elect Directors shall cease,
(y) the term of any Directors elected by the holders of Preferred Stock as a
class shall terminate, and (z) the number of Directors shall be such number as
may be provided for in the certificate of incorporation or by-laws irrespective
of any increase made pursuant to the provisions of paragraph (C)(ii) of this
Section 3 (such number being subject, however, to change thereafter in any
manner provided by law or in the certificate of incorporation or by-laws). Any
vacancies in the Board of Directors effected by the provisions of clauses (y)
and (z) in the preceding sentence may be filled by a majority of the remaining
Directors.

        (D) Except as set forth herein, holders of Series A Junior
Participating Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

                                       6
   37
        Section 4. CERTAIN RESTRICTIONS.
                   --------------------

        (A) Whenever quarterly dividends or other dividends or distributions
payable on the Series A Junior Participating Preferred Stock as provided in
Section 2 are in arrears, thereafter and until all accrued and unpaid dividends
and distributions, whether or not declared, on shares of Series A Junior
Participating Preferred Stock outstanding shall have been paid in full, the
Corporation shall not

                               (i) declare or pay dividends on, make any other 
              distributions on, or redeem or purchase or otherwise acquire for 
              consideration any shares of stock ranking junior (either as to 
              dividends or upon liquidation, dissolution or winding up) to the 
              Series A Junior Participating Preferred Stock;

                               (ii) declare or pay dividends on or make any 
              other distributions on any shares of stock ranking on a parity
              (either as to dividends or upon liquidation, dissolution  or
              winding up) with the Series A Junior Participating Preferred
              Stock, except dividends paid ratably on the Series A Junior
              Participating Preferred Stock and all such parity stock on which
              dividends are payable or in arrears in proportion to the
              total amounts to which the holders of all such shares are then
              entitled;    
                                                                             
                               (iii) redeem or purchase or otherwise acquire 
              for consideration shares of any stock ranking on a parity (either
              as to dividends or upon liquidation, dissolution or winding up)
              with the Series A Junior Participating Preferred Stock,
              provided that the Corporation may at any time redeem, purchase
              or otherwise acquire shares of any such parity stock in
              exchange for shares of any stock of the Corporation ranking
              junior (either as to dividends or upon dissolution, liquidation
              or winding up) to the Series A Junior Participating Preferred
              Stock;

                               (iv) purchase or otherwise acquire for 
              consideration any shares of Series A Junior Participating 
              Preferred Stock, or any

                                       7
   38
              shares of stock ranking on a parity with the Series A Junior
              Participating Preferred Stock, except in accordance with a
              purchase offer made in writing or by publication (as determined
              by the Board of Directors) to all holders of such shares upon
              such terms as the Board of Directors, after consideration of
              the respective annual dividend rates and other relative rights
              and preferences of the respective series and classes, shall
              determine in good faith will result in fair and equitable
              treatment among the respective series or classes.

        (B) The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (A) of
this Section 4, purchase or otherwise acquire such shares at such time and in
such manner.

        Section 5. REACQUIRED SHARES. Any shares of Series A Junior
Participating Preferred Stock purchased or otherwise acquired by the
Corporation in any manner whatsoever shall be retired and cancelled promptly
after the acquisition thereof. All such shares shall upon their cancellation
become authorized but unissued shares of Preferred Stock and may be reissued as
part of a new series of Preferred Stock to be created by resolution or
resolutions of the Board of Directors, subject to the conditions and
restrictions on issuance set forth herein.

        Section 6. LIQUIDATION, DISSOLUTION OR WINDING UP. (A) Upon any
liquidation (voluntary or otherwise), dissolution or winding up of the
Corporation, no distribution shall be made to the holders of shares of stock
ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series A Junior Participating Preferred Stock unless, prior
thereto, the holders of shares of Series A Junior Participating Preferred
Stock shall have received $225 per share, plus an amount equal to accrued and
unpaid dividends and distributions thereon, whether or not declared, to the
date of such payment (the "Series A Liquidation Preference"). Following the
payment of the full amount of the Series A Liquidation Preference, no
additional distributions shall be made to the holders of shares of Series A
Junior Participating Preferred Stock unless, prior thereto, the holders of
shares of Common Stock shall have received an

                                       8
   39
amount per share (the "Common Adjustment") equal to the quotient obtained by
dividing (i) the Series A Liquidation Preference by (ii) 100 (as appropriately
adjusted as set forth in subparagraph C below to reflect such events as stock
splits, stock dividends and recapitalizations with respect to the Common Stock)
(such number in clause (ii) immediately above being referred to as the
"Adjustment Number"). Following the payment of the full amount of the Series A
Liquidation Preference and the Common Adjustment in respect of all outstanding
shares of Series A Junior Participating Preferred Stock and Common Stock,
respectively, holders of Series A Junior Participating  Preferred Stock and
holders of shares of Common Stock shall receive their ratable and proportionate
share of the remaining assets to be distributed in the ratio of the Adjustment
Number to one (1) with respect to such Preferred Stock and Common Stock, on a
per share basis, respectively.

        (B) In the event, however, that there are not sufficient assets
available to permit payment in full of the Series A Liquidation Preference and
the liquidation preferences of all other series of preferred stock, if any,
which rank on a parity with the Series A Junior Participating Preferred Stock,
then such remaining assets shall be distributed ratably to the holders of such
parity shares in proportion to their respective liquidation preferences. In
the event, however, that there are not sufficient assets available to permit
payment in full of the Common Adjustment, then such remaining assets shall be
distributed ratably to the holders of Common Stock.

        (C) In the event the Corporation shall at any time after the Rights
Declaration Date (i) declare any dividend on Common Stock payable in shares of
Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the
outstanding Common Stock into a smaller number of shares, then in each such
case the Adjustment Number in effect immediately prior to such event shall be
adjusted by multiplying such Adjustment Number by a fraction the numerator of
which is the number of shares of Common Stock outstanding immediately after
such event and the denominator of which is the number of shares of Common
Stock that were outstanding immediately prior to such event.

                                       9
   40
        Section 7. CONSOLIDATION, MERGER, ETC. In case the Corporation shall
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case the shares
of Series A Junior Participating Preferred Stock shall at the same time be
similarly exchanged or changed in an amount per share (subject to the provision
for adjustment hereinafter set forth) equal to 100 times the aggregate amount
of stock, securities, cash and/or any other property (payable in kind), as the
case may be, into which or for which each share of Common Stock is changed or
exchanged. In the event the Corporation shall at any time after the Rights
Declaration Date (i) declare any dividend on Common Stock payable in shares of
Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the
outstanding Common Stock into a smaller number of shares, then in each such
case the amount set forth in the preceding sentence with respect to the
exchange or change of shares of Series A Junior Participating Preferred Stock
shall be adjusted by multiplying such amount by a fraction the numerator of
which is the number of shares of Common Stock outstanding immediately after
such event and the denominator of which is the number of shares of Common Stock
that were outstanding immediately prior to such event.

        Section 8. REDEMPTION. The outstanding shares of Series A Junior
Participating Preferred Stock may be redeemed at the option of the Board of
Directors as a whole, but not in part, at any time, or from time to time, at a
cash price per share equal to 105 percent of (i) the product of the Adjustment
Number times the Average Market Value (as such term is hereinafter defined)
of the Common Stock, plus (ii) all dividends which on the redemption date have
accrued on the shares to be redeemed and have not been paid, or declared and a
sum sufficient for the payment thereof set apart, without interest. The
"Average Market Value" is the average of the closing sale prices of the Common
Stock during the 30 day period immediately preceding the date before the
redemption date on the Composite Tape for New York Stock Exchange Listed
Stocks, or, if such stock is not quoted on the Composite Tape, on the New York
Stock Exchange, or, if such stock is not listed on such Exchange, on the
principal United States securities exchange registered under the Securities
Exchange Act of 1934, as amended, on which such

                                       10
   41
stock is listed, or, if such stock is not listed on any such exchange, the
average of the closing sale prices with respect to a share of Common Stock
during such 30-day period, as quoted on the National Association of Securities
Dealers, Inc. Automated Quotations System or any system then in use, or if no
such quotations are available, the fair market value of the Common Stock as
determined by the Board of Directors in good faith.

        Section 9. RANKING. The Series A Junior Participating Preferred Stock
shall rank junior to all other series of the Corporation's Preferred Stock as
to the payment of dividends and the distribution of assets, unless the terms of
any such series shall provide otherwise.

        Section 10. AMENDMENT. The Restated Certificate of Incorporation, as
amended, of the Corporation shall not be further amended in any manner which
would materially alter or change the powers, preferences or special rights of
the Series A Junior Participating Preferred Stock so as to affect them
adversely without the affirmative vote of the holders of a majority or more of
the outstanding shares of Series A Junior Participating Preferred Stock, voting
separately as a class.

        Section 11. FRACTIONAL SHARES. Series A Junior Participating Preferred
Stock may be issued in fractions of a share which shall entitle the holder,
in proportion to such holders fractional shares, to exercise voting rights,
receive dividends, participate in distributions and to have the benefit of all
other rights of holders of Series A Junior Participating Preferred Stock.

        IN WITNESS WHEREOF, we have executed and subscribed this Certificate
and do affirm the foregoing as true under the penalties of perjury this 2nd day
of December   , 1986.

                                     /s/ Robert A. Charpie
                                     ----------------------
                                     President

Attest:

/s/ Walter F. Greeley
- ----------------------
Secretary


                                       11
   42

                                                               Exhibit 3(a)

                            CERTIFICATE OF AMENDMENT
                            ------------------------

                                       OF
                                       --

                     RESTATED CERTIFICATE OF INCORPORATION
                     -------------------------------------

     CABOT CORPORATION, a corporation organized and existing under and by
virtue of the General Corporation Law of the State of Delaware,

DOES HEREBY CERTIFY:

     FIRST: That the Board of Directors of said Corporation, at a meeting
duly held on November 14, 1986, adopted votes setting forth proposed
amendments to the Restated Certificate of Incorporation of said
Corporation, declaring said amendments to be advisable and recommending
the adoption of said amendments by vote of the stockholders of the
Corporation at its Annual Meeting of Stockholders called for February 13,
1987. The votes setting forth the proposed amendments are as follows:

     VOTED: That it is advisable for this Corporation to amend its
Restated Certificate of Incorporation by the proposed amendments
described below and that this board recommends the adoption of such
proposed amendments by vote of the Corporation at its Annual Meeting of
Stockholders called for February 13, 1987:

a. To delete paragraph (i) of Article EIGHTH and insert in its place the
   new paragraph (i) of Article EIGHTH as follows:

   (i)(1) No director of this corporation shall be personally liable to
   the corporation or its stockholders for monetary damages for breach
   of fiduciary duty as a director, except for liability (i) for any
   breach of the director's duty of loyalty to this corporation or its
   stockholders, (ii) for acts or omissions not in good faith or which
   involve intentional misconduct or a knowing violation of law, (iii)
   under Section 174 of the Delaware General Corporation Law, as the
   same exists or hereafter may be amended, or (iv) for any transaction
   from which the director derived an improper personal benefit. If the
   Delaware General Corporation Law is hereafter amended to authorize
   the further elimination or limitation of this liability of directors,
   then the liability of a director of the corporation, in addition to
   the limitation on personal liability provided herein, shall be
   limited to the fullest extent permitted by the amended Delaware
   General Corporation Law. Any repeal or modification of this Article
   by the stockholders of this corporation shall be prospective only,
   and shall not adversely affect any limitation on the personal
   liability of a director of this corporation for acts or omissions
   prior to such repeal or modification.

   43

       (2) No officer or employee of this corporation shall be liable to
   this corporation for any loss or damage suffered by it on account of
   any action taken or omitted to be taken by him in good faith as an
   officer or employee of this corporation, if such person exercised or
   used the same degree of care and skill as a prudent man would have
   exercised or used under the circumstances in the conduct of his own
   affairs.

       (3) For purposes of determining compliance with this paragraph
   (i) , any director, officer or employee of this corporation shall be
   deemed to have taken actions or omitted to take actions in good faith
   if the action taken or omitted to be taken by him or her was taken or
   omitted in reliance in good faith upon the advice of counsel for this
   corporation, or the books of account or other records of this
   corporation, or reports or information made or furnished to this
   corporation by any official, accountant, engineer, agent, or employee
   of this corporation, or by any independent public accountant or
   auditor, counsel, engineer, appraiser, investment banker or other
   expert retained or employed by this corporation, by the directors, by
   any committee of the board of directors of this corporation or by any
   authorized officer of this corporation.

b. To delete paragraph (j) of Article EIGHTH and insert in its place a
   new paragraph (j) of Article EIGHTH as follows:

   (j) The corporation shall indemnify any person who was or is a party
   or is threatened to be made a party to any threatened, pending or
   completed action, suit or proceeding, whether civil, criminal,
   administrative or investigative (and whether or not by or in the
   right of the corporation) by reason of the fact that he is or was a
   director, officer, employee or agent of the corporation, or is or was
   serving at the request of the corporation as a director, officer,
   employee or agent of another company, partnership, joint venture,
   trust or other enterprise, or is or was serving as a fiduciary of any
   employee benefit plan, fund or program sponsored by the corporation
   or such other company, partnership, joint venture, trust or other
   enterprise, against expenses (including attorneys' fees), judgments,
   fines and amounts paid in settlement actually and reasonably incurred
   by him in connection with such action, suit or proceeding, to the
   extent and under the circumstances permitted by the General
   Corporation Law of The State of Delaware as amended from time to
   time. Such indemnification (unless ordered by a court) shall be made
   as authorized in a specific case upon a determination that
   indemnification of the director, officer, employee or agent is proper
   in the circumstances because he has met the applicable standards of
   conduct set forth in the General Corporation Law of the State of
   Delaware Such determination shall be made (1) by the board of
   directors by a majority vote of a quorum consisting of directors who
   were not parties to such action, suit or proceeding, or (2) if such
   quorum is not obtainable, or even if obtainable a quorum of
   disinterested directors so directs, by independent legal counsel in a
   written opinion, or (3) by the stockholders. The foregoing right of
   indemnification shall not be deemed exclusive of any other rights to
   which those seeking indemnification may be entitled under any by-law,
   agreement, vote of stockholders or disinterested directors or
   otherwise, and shall continue as to a person who has ceased to be a
   director, officer, employee or agent and shall inure to the benefit
   of the heirs, executors and administrators of such a person.

   44

      VOTED That it is advisable for this Corporation to amend its
Restated Certificate of Incorporation by the proposed amendments
described below and that this board recommends the adoption of such
proposed amendments by vote of the Corporation at its Annual Meeting of
Stockholders called for February 13, 1987:

a. To delete paragraph (c) of Article EIGHTH and insert in its place the
   new paragraph (c) of Article EIGHTH as follows:

   (c) By-laws may be made, altered, amended or repealed by (i) the
   affirmative vote of the holders of at least seventy-five percent
   (75%) of the voting power of the shares of the then outstanding
   shares of stock of all classes and series of this corporation
   entitled to vote generally in the election of directors voting
   together as a single class or (ii) a vote of the majority of the
   directors then in office at any annual, regular, or special
   stockholders or directors meeting, called for that purpose, the
   notice of which shall specify the subject matter of the proposed new
   by-law or the alteration, amendment, or repeal of an existing by-law,
   or the articles to be affected thereby. Any by-law whether made,
   altered, amended, or repealed by the stockholders or directors may be
   repealed, amended, further amended, or reinstated, as the case may
   be, by either the stockholders or the directors as aforesaid.

b. To add a new paragraph (k) to Article EIGHTH of the Restated
   Certificate of Incorporation as follows:

   (k) Any action required or permitted to be taken by the stockholders
   of the corporation must be taken at a duly called annual or special
   meeting of the stockholders of the corporation and may not be taken
   by any consent in writing by such stockholders.

c. To delete the last paragraph of Article ELEVENTH commencing with the
   word "Notwithstanding" and insert the following in its place:

   Notwithstanding any provision of law, this restated certificate of
   incorporation or the by-laws of this corporation (and notwithstanding
   the fact that a lesser percentage may be specified by law, this
   restated certificate of incorporation or the by-laws of this
   corporation), and in addition to any affirmative vote of the holders
   of any class of preferred stock of this corporation outstanding or
   any other class of capital stock of this corporation or any series of
   any of the foregoing then outstanding which is required by law or by
   or pursuant to this restated certificate of incorporation, the
   affirmative vote of the holders of seventy--five percent (75%) or more
   of the voting power of the shares of the then outstanding shares of
   stock of all classes and series of this corporation entitled to vote
   generally in the election of directors, voting together as a single
   class, shall be required to alter, amend or repeal paragraph (a),
   (b), (c) or (k) of Article EIGHTH, Article TENTH or this Article
   ELEVENTH of this restated certificate of incorporation or to adopt
   any provision inconsistent therewith.

   45

     SECOND: That thereafter, pursuant to vote of its Board of Directors,
the Annual Meeting of Stockholders of said Corporation was duly called
and held, upon notice in accordance with Section 222 of the General
Corporation Law of the State of Delaware, at which meeting the necessary
number of shares as required by statute were voted in favor of the
amendments.

     THIRD: That said amendments were duly adopted in accordance with the
applicable provision of Section 242 of the General Corporation Law of the
State of Delaware.

     FOURTH: That the capital of said Corporation shall not be reduced
under or by reason of said amendment.

      IN WITNESS WHEREOF, said CABOT CORPORATION has caused this
certificate to be signed by Robert A. Charpie, its Chairman, and attested
by Charles D. Gerlinger, its Assistant Secretary this 13th day of
February, 1987.

ATTEST:                                         CABOT CORPORATION


/s/ Charles D. Gerlinger                     By /s/ Robert A. Charpie
- ------------------------                        ----------------------
Assistant Secretary                             Chairman
   46

                                                            EXHIBIT 3(a)
                CERTIFICATE OF DESIGNATIONS

         SERIES B ESOP CONVERTIBLE PREFERRED STOCK

                           of

                     CABOT CORPORATION

          Pursuant to Section 151 of the General
         Corporation Law of the State of Delaware
         ----------------------------------------


          I, Samuel W. Bodman, Chairman of the Board of the
Cabot Corporation ("Company"), a corporation organized and
existing under the General Corporation Law of the State of
Delaware, in accordance with the provisions of Section 151
thereof, DO HEREBY CERTIFY that, pursuant to the authority
conferred upon the Board of Directors by the Restated
Certificate of Incorporation of the Company, as amended, the
Board of Directors authorized the series of Preferred Stock
hereinafter provided for and established the voting powers
thereof and authorized an Executive Committee of the Board of
Directors to adopt, and said Committee has adopted, the
following resolution creating a series of 200,000 shares of
Preferred Stock, $1.00 par value, designated as Series B ESOP
Convertible Preferred Stock:

          VOTED: That, pursuant to the authority vested in
the Board of Directors of the Company in accordance with the
provisions of its Restated Certificate of Incorporation, as
amended, and pursuant to the authority vested in the


   47

Executive Committee by the Board of Directors a series of
Preferred Stock of the Company be, and it hereby is, created,
and that the designation and amount thereof and the voting
powers, preferences and relative, participating, optional or
other special rights of the shares of such series, and the
qualifications, limitations or restrictions thereof, are as
follows:

                Section 1. Designation and Amount; Special Purpose
                -------    ---------------------------------------
Restricted Transfer Issue.
- -------------------------

          (A) The shares of this series of Preferred Stock
shall be designated as Series B ESOP Convertible Preferred
Stock ("Series B Preferred Stock") and the number of shares
constituting such series shall be 200,000.

          (B) Shares of Series B Preferred Stock shall be
 issued only to a trustee or trustees (or to any successor
 trustee or trustees) acting on behalf of one or more employee
 stock ownership plans or other employee benefit plans of the
 Company (the "Trustee"). Certificates representing shares of
 Series B Preferred Stock shall be legended to reflect any
 restrictions on transfer imposed on such shares at the time
 of issuance. Notwithstanding the foregoing provisions of
 this paragraph (B) of Section 1, shares of Series B Preferred
 Stock (i) may be converted into shares of Common Stock as
 provided by Section 5 hereof and the shares of Common Stock
 issued upon such conversion may be transferred by the holder


                              -2-

   48

thereof as permitted by law and (ii) shall be redeemable by
the Company or by the holder upon the terms and conditions
provided by Sections 6, 7 and 8 hereof.

             Section 2.   Dividends and Distributions.
             -------      ---------------------------

             (A) Subject to the provisions for adjustment
hereinafter set forth, the holders of shares of Series B
Preferred Stock shall be entitled to receive, when, as and if
declared by the Board of Directors out of funds legally
available therefor, cash dividends ("Preferred Dividends") in
an amount per share equal to $ 77.50 per share per annum, and
no more, payable quarterly, in arrears, one-quarter on the
last business day of each calendar quarter (each a "Dividend
Payment Date") commencing on December 30, 1988, to holders of
record at the start of business on such Dividend Payment
Date. Preferred Dividends shall begin to accrue on
outstanding shares of Series B Preferred Stock from the date
of issuance of such shares of Series B Preferred Stock.
Preferred Dividends shall accrue on a daily basis whether or
not declared and whether or not the Company shall have
earnings or surplus out of which such dividends could be paid
at the time, and Preferred Dividends accrued on the shares of
Series B Preferred Stock for any period less than a full
quarterly period between Dividend Payment Dates shall be
computed on the basis of a 360-day year of 30-day months.
Accumulated but unpaid Preferred Dividends shall cumulate as

                           -3-

   49

of the Dividend Payment Date on which they first became
payable, but no interest shall accrue on accumulated but
unpaid Preferred Dividends.

          (B) So long as any Series B Preferred Stock shall
be outstanding, no dividend shall be declared or paid or set
apart for payment on any other series of stock ranking on a
parity with the Series B Preferred Stock as to dividends,
unless there shall also be or have been declared and paid or
set apart for payment on the Series B Preferred Stock like
dividends for all dividend payment periods of the Series B
Preferred Stock ending on or before the dividend payment date
of such parity stock, ratably in proportion to the respective
amounts of dividends accumulated and unpaid through such
dividend payment period on the Series B Preferred Stock and
accumulated and unpaid or payable on such parity stock
through the dividend payment period on such parity stock
ending on such dividend payment date. In the event that full
cumulative dividends on the Series B Preferred Stock have not
been declared and paid or set apart for payment when due, the
Company shall not declare or pay or set apart for payment any
dividends or make any other distributions on, or make any
payment on account of the purchase, redemption or other
retirement of, any other class of stock or series thereof of
the Company ranking, as to dividends or as to distributions
in the event of a liquidation, dissolution or winding-up of

                            -4-

   50

the Company, junior to the Series B Preferred Stock until
full cumulative dividends on the Series B Preferred Stock
shall have been declared and paid or declared and set aside
for payment; PROVIDED, HOWEVER, that the foregoing shall not
apply to (i) any dividend payable solely in any shares of any
stock ranking, as to dividends or as to distributions in the
event of a liquidation, dissolution or winding-up of the
Company, junior to the Series B Preferred Stock, (ii) the
purchase of shares of any stock ranking, as to dividends or
as to distributions in the event of a liquidation,
dissolution or winding-up of the Company, junior to the
Series B Preferred Stock either (A) pursuant to any employee
or director incentive or benefit plan or arrangement
(including any employment, severance or consulting agreement)
of the Company or any subsidiary of the Company heretofore or
hereafter adopted or (B) in exchange solely for shares of any
other stock ranking, as to dividends or as to distributions
in the event of a liquidation, dissolution or winding up of
the Company, junior to the Series B Preferred Stock, or (iii)
any payment made in respect of the purchase or redemption of
the Rights, as defined in paragraph (F) of Section 5 hereof,
or any rights similar thereto.

               SECTION 3.    VOTING RIGHTS. The holders of
 shares of Series B Preferred Stock shall have the following
 voting rights:

                               -5-

   51

          (A) The holders of Series B Preferred Stock shall
be entitled to vote on all matters submitted to a vote of the
holders of Common Stock of the Company, voting together with
the holders of Common Stock (and holders of any other class
or series of stock which may similarly be entitled to vote
with the shares of Common Stock) as one class. Each share of
the Series B Preferred Stock shall be entitled to the number
of votes equal to the number of shares of Common Stock into
which such share of Series B Preferred Stock could be
converted on the record date for determining the stockholders
entitled to vote, rounded down to the nearest vote; it being
understood that whenever the "Conversion Price" (as defined
in Section 5 hereof) is adjusted as provided in Section 9
hereof, the voting rights of the Series B Preferred Stock
shall also be similarly adjusted.

          (B) Except as otherwise required by law or set
 forth herein, holders of Series B Preferred Stock shall have
 no special voting rights and their consent shall not be
 required (except to the extent they are entitled to vote with
 holders of Common Stock and holders of any other class or
 series of stock which may similarly be entitled to vote with
 the shares of Common Stock) for the taking of any corporate
 action. Any increase or decrease in the authorized class of
 Preferred Stock (but not below the number of shares thereof
 then outstanding) shall not be deemed to alter or change the

                            -6-

   52

powers, preferences, or special rights of the shares of Series
B Preferred Stock so as to affect them adversely within the
meaning of the General Corporation Law of the State of
Delaware.

          Section 4.     Liquidation, Dissolution or Winding Up.
                         ---------------------------------------

          (A) Upon any voluntary or involuntary liquidation,
dissolution or winding up of the Company, the holders of Series
B Preferred Stock shall be entitled to receive out of the
assets of the Company which remain after satisfaction in full
of all valid claims of creditors of the Company and which are
available for payment to stockholders and subject to the rights
of the holders of any stock of the Company ranking senior to or
on a parity with the Series B Preferred Stock in respect of
distributions upon liquidation, dissolution or winding up of
the Company, before any amount shall be paid or distributed
among the holders of Common Stock or any other shares ranking
junior to the Series B Preferred Stock in respect of
distributions upon liquidation, dissolution or winding up of
the Company, liquidating distributions in the amount of $1,000
per share, plus an amount equal to all accumulated and unpaid
dividends (including dividends declared and set aside) and
accrued dividends thereon to the date fixed for distribution,
and no more. If upon any liquidation, dissolution or winding
up of the Company, the amounts payable with respect to the

                           -7-

   53

Series B Preferred Stock and any other stock ranking as to
any such distribution on a parity with the Series B Preferred
Stock are not paid in full, the holders of the Series B
Preferred Stock and such other stock shall share ratably in
any distribution of assets in proportion to the full
respective preferential amounts to which they are entitled.
After payment of the full amount to which they are entitled
as provided by the foregoing provisions of this paragraph
4(A), the holders of shares of Series B Preferred Stock shall
not be entitled to any further right or claim to any of the
remaining assets of the Company.

          (B) Neither the merger or consolidation of the
Company with or into any other corporation or other entity,
nor the merger or consolidation of any other corporation or
other entity with or into the Company, nor the sale, transfer
or lease of all or any portion of the assets of the Company,
shall be deemed to be a liquidation, dissolution or winding
up of the Company for purposes of this Section 4, but the
holders of Series B Preferred Stock shall nevertheless be
entitled in the event of any such merger or consolidation to
the rights provided by Section 8 hereof.

          (C) Written notice of any voluntary or involuntary
 liquidation, dissolution or winding up of the Company,
 stating the payment date or dates when, and the place or
 places where, the amounts distributable to holders of Series

                             -8-

   54

B Preferred Stock in such circumstances shall be payable,
shall be given by first-class mail, postage prepaid, mailed
not less than twenty (20) days prior to any payment date
stated therein, to the holders of Series B Preferred Stock,
at the address shown on the books of the Company or any
transfer agent for the Series B Preferred Stock.

          Section 5.    Conversion into Common Stock.
          -------       ----------------------------

          (A) A holder of shares of Series B Preferred Stock
shall be entitled, at any time prior to the close of business
on the date fixed for redemption of such shares pursuant to
Section 6, 7 or 8 hereof, to cause any or all of such shares
to be converted into shares of Common Stock, initially at a
conversion rate equal to the ratio of $1,000 to the amount
which initially shall be $ 45.73 and which shall be adjusted
as hereinafter provided (such amount, as so adjusted, is
hereinafter sometimes referred to as the "Conversion Price")
(that is, a conversion rate initially equivalent to 21.8675
shares of Common Stock for each share of Series B Preferred
Stock so converted but that is subject to adjustment as the
Conversion Price is adjusted as hereinafter provided).

          (B) Any holder of shares of Series B Preferred
 Stock desiring to convert such shares into shares of Common
 Stock shall surrender the certificate or certificates
 representing the shares of Series B Preferred Stock being

                             -9-

   55

converted, duly assigned or endorsed for transfer to the
Company (or accompanied by duly executed stock powers
relating thereto), at the principal executive office of the
Company or the offices of the transfer agent for the Series B
Preferred Stock or such office or offices in the continental
United States of an agent for conversion as may from time to
time be designated by notice to the holders of the Series B
Preferred Stock by the Company or the transfer agent for the
Series B Preferred Stock, accompanied by written notice of
conversion, on any day which is a business day in the city of
Boston, Massachusetts. Such notice of conversion shall
specify (i) the number of shares of Series B Preferred Stock
to be converted and the name or names in which such holder
wishes the certificate or certificates for Common Stock to be
issued and for any shares of Series B Preferred Stock not to
be so converted to be issued (subject to compliance with
applicable legal requirements if any of said certificates are
to be issued in a name other than the name of the holder),
and (ii) the address to which such holder wishes delivery to
be made of such new certificates to be issued upon such
conversion.

           (C) Upon surrender of a certificate representing a
share or shares of Series B Preferred Stock for conversion,
the Company shall, as promptly as practicable after such
surrender, issue and send by hand delivery (with receipt to

                              -10-

   56

be acknowledged) or by first class mail, postage prepaid, to
the holder thereof or to such holder's designee, at the
address designated by such holder, a certificate or
certificates for the number of shares of Common Stock to
which such holder shall be entitled upon conversion. In the
event that there shall have been surrendered a certificate or
certificates representing shares of Series B Preferred Stock,
only part of which are to be converted, the Company shall
issue and deliver to such holder or such holder's designee a
new certificate or certificates representing the number of
shares of Series B Preferred Stock which shall not have been
converted.

          (D) A conversion of shares of Series B Preferred
Stock into shares of Common Stock made at the option of the
holder thereof shall be effective as of the close of business
on the day on which the Company receives written notice of
conversion pursuant to paragraph (B) of this Section 5. On
and after the effective day of conversion, the shares of
Series B Preferred so converted shall no longer be deemed to
be outstanding for any purpose, and the person or persons
entitled to receive the Common Stock issuable upon such
conversion shall be treated for all purposes as the record
holder or holders of such shares of Common Stock, but no
allowance or adjustment shall be made in respect of dividends
payable to holders of Common Stock of record on any date

                            -11-

   57

prior to such effective date. The Company shall not be obligated
to pay any dividends which shall have been declared and shall be
payable to holders of shares of Series B Preferred Stock on a
Dividend Payment Date if such Dividend Payment Date for such
dividend shall be on or subsequent to the effective date of
conversion of such shares, unless such declared dividends have
been set aside for payment prior to the effective date of
conversion of such shares, which dividends shall be paid on the
effective date of conversion.

          (E) The Company shall not be obligated to deliver to
holders of Series B Preferred Stock any fractional shares of
Common Stock issuable upon any conversion of such shares of
Series B Preferred Stock, but in lieu thereof may make a cash
payment in respect thereof in any manner permitted by law. Such
cash payment shall be in an amount equal to such fraction
multiplied by the Fair Market Value per share of the Common Stock
(as defined in Section 9 hereof) at the close of business on the
day of conversion.

          (F) Prior to the Distribution Date (as defined in Section
 3(a) of the Rights Agreement (defined below), if the Company
 shall issue shares of Common Stock upon conversion of shares of
 Series B Preferred Stock as contemplated by this Section 5, the
 Company shall issue together with each such share of Common Stock
 one right (a "Right", and collectively the "Rights") to purchase
 Series A Junior Participating Preferred Stock of the Company (or

                              -12 -

   58

other securities in lieu thereof) pursuant to the Rights
Agreement dated as of November 14, 1986, and amended and
restated as of August 12, 1988, between the Company and The
First National Bank of Boston, as Rights Agent, as such
agreement may from time to time be amended (the "Rights
Agreement"), or any rights issued to holders of Common Stock
of the Company in addition thereto or in replacement
therefor.

          (G) The Company shall at all times reserve and
keep available out of its authorized and unissued Common
Stock, solely for issuance upon the conversion of shares of
Series B Preferred Stock as herein provided, free from any
preemptive rights, such number of shares of Common Stock as
shall from time to time be issuable upon the conversion of
all the shares of Series B Preferred Stock then outstanding.
Notwithstanding the foregoing, the Company shall be entitled
to deliver upon conversion of shares of Series B Preferred
Stock, as herein provided, shares of Common Stock reacquired
and held in the treasury of the Company (in lieu of the
issuance of authorized and unissued shares of Common Stock),
so long as any such treasury shares are free and clear of all
liens, charges, security interests or encumbrances. The
Company shall prepare and shall use its best efforts to
obtain and keep in force such governmental or regulatory
permits or other authorizations as may be required by law,


                          -13-

   59

and shall comply with all requirements as to registration or
qualification of the Common Stock (and all requirements to
list the Common Stock which are at the time applicable) as
shall from time to time be sufficient to effect the
conversion of all shares of Series B Preferred Stock then
outstanding and convertible into shares of Common Stock.

         Section 6.    Redemption At the Option of the Company.
         -------       ---------------------------------------

         (A) The Series B Preferred Stock shall be redeemable, 
in whole or in part, at the option of the Company at any time 
after November 18, 1991, or on or before November 18, 1991 if 
permitted by paragraph (C) or (D) of this Section 6, at the 
following redemption prices per share (or, if pursuant to 
paragraph (C) of this Section 6, at the redemption price set 
forth therein):



           DURING THE TWELVE-
           MONTH PERIOD                 PRICE PER
           BEGINNING NOVEMBER 19        SHARE
           ---------------------        ---------

                                     
                1988 ..........         $1077.50
                1989 ..........         $1069.75
                1990 ..........         $1062.00
                1991 ..........         $1054.25
                1992 ..........         $1046.50
                1993 ..........         $1038.75
                1994 ..........         $1031.00
                1995 ..........         $1023.25
                1996 ..........         $1015.50
                1997 ..........         $1007.75
        

 and thereafter at $1,000 per share, plus, in each case, an
 amount equal to all accumulated and unpaid dividends and
 accrued dividends thereon to the date fixed for redemption.

                               -14-

   60

Payment of the redemption price shall be made by the Company in
cash or shares of Common Stock, or a combination thereof, as
permitted by paragraph (E) of this Section 6. From and after
the close of business on the date fixed for redemption,
dividends on shares of Series B Preferred Stock called for
redemption will cease to accrue, such shares will no longer be
deemed to be outstanding and all rights in respect of such
shares of the Company shall cease, except the right to receive
the redemption price, provided that shares of Series B Preferred
Stock may be converted pursuant to Section 5 hereof at any time
prior to the close of business on the date fixed for redemption
of such shares pursuant to Sections 6, 7 or 8 hereof. If less
than all of the outstanding shares of Series B Preferred Stock
are to be redeemed, the Company shall either redeem a portion of
the shares of each holder determined pro rata based on the
number of shares held by each holder or shall select the shares
to be redeemed by lot or by any other manner deemed equitable,
as may be determined by the Board of Directors of the Company.

          (B) Unless otherwise required by law, notice of
redemption with respect to a redemption under this Section 6
(but not Section 7 or 8) will be sent to the holders of Series B
Preferred Stock at the address shown on the books of the Company
or any transfer agent for the Series B Preferred Stock by first
class mail, postage prepaid, mailed not less than twenty (20)
days nor more than sixty (60) days prior to the redemption date.

                              -15-

   61

Each such notice shall state: (i) the redemption date; (ii)
the total number of shares of the Series B Preferred Stock
to be redeemed and, if fewer than all the shares held by
such holder are to be redeemed, the number of such shares to
be redeemed from such holder; (iii) the redemption price;
(iv) the place or places where certificates for such shares
are to be surrendered for payment of the redemption price;
(v) that dividends on the shares to be redeemed will cease
to accrue on such redemption date; and (vi) the conversion
rights of the shares to be redeemed, the period within which
conversion rights may be exercised, and the Conversion Price
and number of shares of Common Stock issuable upon
conversion of a share of Series B Preferred Stock at the
time. Upon surrender of the certificates for any shares
called for redemption pursuant to the provisions of this
Section 6 or the provisions of Sections 7 or 8 hereof, which
shares have not previously been converted (properly endorsed
or assigned for transfer, if the Board of Directors of the
Company shall so require and the notice shall so state),
such shares shall be redeemed by the Company at the date
fixed for redemption and at the applicable redemption price
set forth in this Section 6 or in Sections 7 or 8 hereof.

          (C) In the event (i) of a change in the federal tax
law of the United States of America which has the effect of
precluding the Company from claiming any of the tax deductions

                             -16-

   62

for dividends paid on the Series B Preferred Stock when such
dividends are used as provided under Section 404(k)(2) of the
Internal Revenue Code of 1986, as amended and in effect on the
date shares of Series B Preferred Stock are initially issued,
(ii) that shares of Series B Preferred Stock are held by an
employee benefit plan intended to qualify as an employee stock
ownership plan within the meaning of Section 4975 of the Internal
Revenue Code of 1986, as amended, and such plan does not so
qualify, or (iii) that the Company, in good faith after
consultation with counsel to the Company, determines that the
voting provisions contained herein are not in compliance with
Rule 19c-4 promulgated by the Securities and Exchange Commission
under the Securities Exchange Act of 1934, as amended, the
Company may, in its sole discretion and notwithstanding anything
to the contrary in paragraph (A) of this Section 6, elect to
redeem such shares at a redemption price equal to the amount
payable in respect of the shares upon liquidation of the Company
pursuant to Section 4 hereof (including the amount equal to all
accumulated and unpaid dividends and accrued dividends thereon to
the date fixed for redemption, as provided by Section 4 hereof).

          (D) Notwithstanding anything to the contrary in
paragraph (A) of this Section 6, the Company may, in its sole
discretion, elect to redeem any or all of the shares of

                             -17-

   63

Series B Preferred Stock at any time on or prior to November
18, 1991 on the terms and conditions set forth in paragraphs
(A) and (B) of this Section 6, if the last reported sales
price, regular way, of a share of Common Stock, as reported
on the New York Stock Exchange Composite Tape or, if the
Common Stock is not listed or admitted to trading on the New
York Stock Exchange, on the principal national securities
exchange on which such stock is listed or admitted to trading
or, if the Common Stock is not listed or admitted to trading
on any national securities exchange, on the National Market
System of the National Association of Securities Dealers,
Inc. Automated Quotation System ("NASDAQ") or, if the Common
Stock is not quoted on such National Market System, the
average of the closing bid and asked prices in over-the-
counter market as reported by NASDAQ, for at least twenty
(20) trading days within a period of thirty (30) consecutive
trading days ending within five (5) days of the notice of
redemption, equals or exceeds one hundred forty percent
(140%) of the Conversion Price (giving effect equitably in
making such calculation to any adjustments required by
Section 9 hereof).

            (E) The Company, at its option, may make payment
of the redemption price required upon redemption of shares of
Series B Preferred Stock in cash or in shares of Common Stock
(or fractional shares thereof), or in a combination of such

                             -18-

   64

shares and cash, any such shares to be valued for such
purpose at their Fair Market Value (as defined in paragraph G
of Section 9 hereof, provided, however, that in calculating
their Fair Market Value the Adjustment Period shall be deemed
to be the five (5) consecutive trading days preceding, and
including, the date of redemption), except that any payment
required to be made under paragraph (C) of Section 8 shall be
made in cash.

          Section 7.    Other Redemption Rights.
          -------       -----------------------

          (A) Shares of Series B Preferred Stock shall be
redeemed by the Company for cash or, if the Company so
elects, in shares of Common Stock (or fractional shares
thereof), or a combination of such shares and cash, any such
shares of Common Stock to be valued for such purpose at their
Fair Market Value (as defined in paragraph (G) of Section 9
hereof, provided, however, that in calculating their Fair
Market Value the Adjustment Period shall be deemed to be the
five (5) consecutive trading days preceding, and including,
the date of redemption), at the redemption prices per share
set forth in paragraph (B) of this Section 7, at the option
of the holder, at any time and from time to time upon notice
to the Company given not less than five (5) business days
prior to the date fixed by the holder in such notice for such
redemption, when and to the extent necessary (i) for such
holder to provide for distributions required to be made

                         -19-

   65

under, or to satisfy an investment election provided to
participants in accordance with, the Cabot Corporation Employee
Stock Ownership Plan and Trust Agreement, dated as of November
16, 1988, as the same may be amended or any successor plan (the
"Plan"), or (ii) for such holder to make payment of principal,
interest or premium due and payable (whether as scheduled or
upon acceleration) (a) on the $75,000,000 aggregate principal
amount of ESOP Notes Due December 31, 2013 of the trust under
the Plan (but only if to remedy or prevent a default under such
ESOP Notes or related loan documentation, in each case as
amended), or (b) on any other indebtedness incurred by the
holder for the benefit of the Plan (but only if to remedy or
prevent a default thereunder).

          (B) For the purposes of clause (i) of paragraph (A)
of this Section 7, the redemption price of a share of Series B
Preferred Stock shall be an amount equal to the Fair Market
Value (as defined in paragraph G of Section 9 hereof) of such
share of Series B Preferred Stock. For the purposes of clause
(ii) of paragraph (A) of this Section 7, the redemption price
of a share of Series B Preferred Stock shall be equal to the
amount payable in respect of such share upon liquidation of the
Company pursuant to Section 4 hereof (including the amount
equal to all accumulated and unpaid dividends and accrued
dividends thereon to the date fixed for redemption as provided
by Section 4 hereof).

                              -20-

   66

        Section 8.   Consolidation, Merger, etc.
        -------      --------------------------

        (A) In the event that the Company shall consummate
any consolidation or merger or similar transaction, however
named, pursuant to which the outstanding shares of Common
Stock are by operation of law exchanged solely for or
changed, reclassified or converted solely into stock of any
successor or resulting company (including the Company) that
constitutes "qualifying employer securities" with respect to
a holder of Series B Preferred Stock within the meaning of
Section 409(e) of the Internal Revenue Code of 1986, as
amended, and Section 407(c)(5) of the Employee Retirement
Income Security Act of 1974, as amended, or any successor
provisions of law, and, if applicable, for a cash payment in
lieu of fractional shares, if any, the shares of Series B
Preferred Stock of such holder shall be assumed by and shall
become preferred stock of such successor or resulting
company, having in respect of such company insofar as
possible the same powers, preferences and relative,
participating, optional or other special rights (including
the redemption rights provided by Sections 6, 7 and 8
hereof), and the qualifications, limitations or restrictions
thereon, that the Series B Preferred Stock had immediately
prior to such transaction, except that after such transaction
each share of the Series B Preferred Stock shall be
convertible, otherwise on the terms and conditions provided

                           -21-

   67

by Section 5 hereof, into the qualifying employer securities
so receivable by a holder of the number of shares of Common
Stock into which such shares of Series B Preferred Stock
could have been converted immediately prior to such
transaction if such holder of Common Stock failed to exercise
any rights of election to receive any kind or amount of
stock, securities, cash or other property (other than such
qualifying employer securities and a cash payment, if
applicable, in lieu of fractional shares) receivable upon
such transaction (provided that, if the kind or amount of
qualifying employer securities receivable upon such
transaction is not the same for each non-electing share, then
the kind and amount of qualifying employer securities
receivable upon such transaction for each non-electing share
shall be the kind and amount so receivable per share by a
plurality of the non-electing shares). The rights of the
Series B Preferred Stock as preferred stock of such successor
or resulting company shall successively be subject to
adjustments pursuant to Section 9 hereof after any such
transaction as nearly equivalent as practicable to the
adjustments provided for by such section prior to such
transaction. The Company shall not consummate any such
merger, consolidation or similar transaction unless all then
outstanding shares of the Series B Preferred Stock shall be

                            -22-

   68

assumed and authorized by the successor or resulting company
as aforesaid.

         (B) In the event that the Company shall consummate
any consolidation or merger or similar transaction, however
named, pursuant to which the outstanding shares of Common
Stock are by operation of law exchanged for or changed,
reclassified or converted into other stock or securities or
cash or any other property, or any combination thereof, other
than any such consideration which is constituted solely of
qualifying employer securities (as referred to in paragraph
(A) of this Section 8) and cash payments, if applicable, in
lieu of fractional shares, each outstanding share of Series B
Preferred Stock shall, without any action on the part of the
Company or any holder thereof (but subject to paragraph (C)
of this Section 8), be deemed converted by virtue of such
merger, consolidation or similar transaction immediately
prior to such consummation into the number of shares of
Common Stock into which such share of Series B Preferred
Stock could have been converted at such time and each share
of Series B Preferred Stock shall, by virtue of such
transaction and on the same terms as apply to the holders of
Common Stock, be converted into or exchanged for the
aggregate amount of stock, securities, cash or other property
(payable in like kind) receivable by a holder of the number
of shares of Common Stock into which such share of Series B


                           -23-

   69

Preferred Stock could have been converted immediately prior
to such transaction if such holder of Common Stock failed to
exercise any rights of election as to the kind or amount of
stock, securities, cash or other property receivable upon
such transaction (provided that, if the kind or amount of
stock, securities, cash or other property receivable upon
such transaction is not the same for each non-electing share,
then the kind and amount of stock, securities, cash or other
property receivable upon such transaction for each non-
electing share shall be the kind and amount so receivable per
share by a plurality of the non-electing shares).

          (C) In the event the Company shall enter into any
agreement providing for any consolidation or merger or
similar transaction described in paragraph (B) of this
Section 8, then the Company shall as soon as practicable
thereafter (and in any event at least ten (10) business days
before consummation of such transaction) give notice of such
agreement and the material terms thereof to each holder of
Series B Preferred Stock and each such holder shall have the
right to elect, by written notice to the Company, to receive,
upon consummation of such transaction (if and when such
transaction is consummated), from the Company or the
successor of the Company, in lieu of what would otherwise be
the result under paragraph (B) of this Section 8 (and in
redemption and retirement of such share of Series B Preferred

                             -24-

   70

Stock, but without any premium), a cash payment equal to the
amount payable in respect of such share of Series B Preferred
Stock upon liquidation of the Company pursuant to Section 4
hereof, (including an amount equal to all accumulated and
unpaid dividends and accrued dividends thereon to the date
fixed for redemption as provided by Section 4 hereof). No
such notice of redemption shall be effective unless given to
the Company prior to the close of business on the fifth
business day prior to consummation of such transaction,
unless the Company or the successor of the Company shall
waive such prior notice, but any notice of redemption so
given prior to such time may be withdrawn by notice of
withdrawal given to the Company prior to the close of
business on the fifth business day prior to consummation of
such transaction.

          Section 9.    Anti-dilution Adjustments.
          -------       -------------------------

          (A) In the event the Company shall, at any time or
 from time to time while any of the shares of Series B
 Preferred Stock are outstanding, (i) pay a dividend or make a
 distribution in respect of the Common Stock, to the extent
 that such dividend or distribution consists of shares of
 Common Stock, (ii) subdivide the outstanding shares of Common
 Stock, or (iii) combine the outstanding shares of Common
 Stock into a smaller number of shares, in each case whether
 by reclassification of shares, recapitalization of the

                           -25-

   71

Company (excluding a recapitalization effected by a merger or
consolidation to which Section 8 hereof applies) or
otherwise, the Conversion Price in effect immediately prior
to such action shall be adjusted by multiplying such
Conversion Price by the fraction the numerator of which is
the number of shares of Common Stock outstanding immediately
before such event and the denominator of which is the number
of shares of Common Stock outstanding immediately after such
event. An adjustment made pursuant to this paragraph 9(A)
shall be given effect, upon payment of such a dividend or
distribution, as of the record date for the determination of
shareholders entitled to receive such dividend or
distribution (on a retroactive basis) and in the case of a
subdivision or combination shall become effective immediately
as of the effective date thereof.

          (B) In the event that the Company shall, at any
time or from time to time while any of the shares of Series B
Preferred Stock are outstanding, issue to holders of shares
of Common Stock as a dividend or distribution, including by
way of a reclassification of shares or a recapitalization of
the Company, rights or warrants to purchase shares of Common
Stock (but not including as such rights or warrants the
Rights (as defined in Section 5 hereof) or any securities
convertible into or exchangeable for shares of Common Stock)
at a purchase price per share less than the Fair Market Value

                           -26-

   72

(as hereinafter defined) of a share of Common Stock on the
date of issuance of such rights or warrants, to the extent
that such dividend or distribution consists of such rights or
warrants, then, subject to the provisions of paragraphs (E)
and (F) of this Section 9, the Conversion Price shall be
adjusted by multiplying such Conversion Price by the fraction
the numerator of which shall be the number of shares of
Common Stock outstanding immediately before such issuance of
rights or warrants plus the number of shares of Common Stock
which could be purchased at the Fair Market Value of a share
of Common Stock at the time of such issuance for the maximum
aggregate consideration payable upon exercise in full of all
such rights or warrants and the denominator of which shall be
the number of shares of Common Stock outstanding immediately
before such issuance of rights or warrants plus the maximum
number of shares of Common Stock that could be acquired upon
the exercise in full of all such rights and warrants.

         (C) In the event the Company shall, at any time or
from time to time while any of the shares of Series B
Preferred Stock are outstanding, make an Extraordinary
Distribution (as hereinafter defined) in respect of the
Common Stock, whether by dividend, distribution,
reclassification of shares or recapitalization of the Company
(excluding a recapitalization or reclassification effected by
a merger or consolidation to which Section 8 hereof applies)

                          -27-

   73

or effect a Pro Rata Repurchase (as hereinafter defined) of
Common Stock where the aggregate amount paid in the
Extraordinary Distribution or the aggregate premium paid in
the Pro Rata Repurchase over the Fair Market Value of the
shares of Common Stock repurchased (as determined on the
expiration date (including all extensions thereof) of the
applicable tender offer or exchange offer), either alone or
when combined with aggregate amounts or premiums paid in
respect of any other Extraordinary Distributions or Pro Rata
Repurchases effected within the preceding twelve-month period
(which other Extraordinary Distributions or Pro Rata
Repurchases have not been previously taken into account for
the purpose of adjusting the Conversion Price pursuant to
this paragraph (C) of Section 9) exceeds twelve and one-half
percent (12 - 1/2%) of the aggregate Fair Market Value of all
shares of Common Stock outstanding on the record date in
respect of such Extraordinary Distribution or on the
expiration date (including all extensions thereof) of the
applicable tender offer or exchange offer in respect of such
Pro Rata Repurchase, as the case may be, the Conversion Price
in effect immediately prior to such Extraordinary
Distribution or Pro Rata Repurchase shall, subject to
paragraphs (E) and (F) of this Section 9, be adjusted by
multiplying such Conversion Price by the fraction the
numerator of which is (i) the product of (x) the number of

                          -28-

   74

shares of Common Stock outstanding immediately before such
Extraordinary Distribution or Pro Rata Repurchase multiplied
by (y) the Fair Market Value of a share of Common Stock on
the record date with respect to an Extraordinary
Distribution, or on the expiration date (including all
extensions thereof) of the applicable tender offer or
exchange offer with respect to a Pro Rata Repurchase minus
(ii) the Fair Market Value of the Extraordinary Distribution
or the aggregate purchase price of the Pro Rata Repurchase,
as the case may be, and the denominator of which shall be the
product of (A) the number of shares of Common Stock
outstanding immediately before such Extraordinary
Distribution or Pro Rata Repurchase minus, in the case of a
Pro Rata Repurchase, the number of shares of Common Stock
repurchased by the Company multiplied by (B) the Fair Market
Value of a share of Common Stock on the record date with
respect to an Extraordinary Distribution or on the expiration
date (including all extensions thereof) of the applicable
tender offer or exchange offer. The Company shall send each
holder of Series B Preferred Stock (i) notice of its intent
to make any Extraordinary Distribution and (ii) notice of any
offer by the Company to make a Pro Rata Repurchase, in each
case at the same time as, or as soon as practicable after,
such offer is first communicated (including by announcement
of a record date in accordance with the rules of any stock


                             -29-

   75

exchange on which the Common Stock is listed or admitted to
trading) to holders of Common Stock. Such notice shall
indicate the intended record date and the amount and nature
of such Extraordinary Distribution, or the number of shares
subject to such offer for a Pro Rata Repurchase and the
purchase price payable by the Company pursuant to such offer,
as well as the Conversion Price and the number of shares of
Common Stock into which a share of Series B Preferred Stock
may be converted at such time.

          (D) In the event the Company shall, at any time or
from time to time while any of the shares of Series B
Preferred Stock are outstanding, issue, sell or exchange
shares of Common Stock (other than pursuant to any employee
or director incentive or benefit plan or arrangement,
including any employment, severance or consulting agreement,
of the Company or any subsidiary of the Company heretofore or
hereafter adopted) for a consideration having a Fair Market
Value on the date of such issuance, sale or exchange of fifty
percent (50%) or less of the Fair Market Value of such shares
on the date of such issuance, sale or exchange, then, subject
to the provisions of paragraphs (E) and (F) of this Section
9, the Conversion Price shall be adjusted by multiplying such
Conversion Price by the fraction the numerator of which shall
be the sum of (i) the Fair Market Value of all the shares of
Common Stock outstanding on the day immediately preceding

                           -30-

   76

such issuance, sale or exchange plus (ii) the Fair Market
Value of the consideration received by the Company in respect
of such issuance, sale or exchange of shares of Common Stock,
and the denominator of which shall be the product of (i) the
Fair Market Value of a share of Common Stock on the day
immediately preceding such issuance, sale or exchange
multiplied by (ii) the sum of the number of shares of Common
Stock outstanding on such day plus the number of shares of
Common Stock so issued, sold or exchanged by the Company.

          (E) Notwithstanding any other provisions of this
Section 9, the Company shall not be required to make
immediately any adjustment of the Conversion Price unless
such adjustment would require an increase or decrease of at
least one percent (1%) in the Conversion Price. Any lesser
adjustment shall be carried forward and shall be made no
later than the earlier of (i) three years after the event
which gives rise to such adjustment and (ii) the time of the
next subsequent adjustment which, together with any
adjustment or adjustments so carried forward, shall amount to
an increase or decrease of at least one percent (1%) in the
Conversion Price.

          (F) If the Company shall make any dividend or
 distribution on the Common Stock or issue any Common Stock,
 other capital stock or other security convertible into or
 exchangeable for capital stock of the Company or any rights


                             -31-

   77

or warrants to purchase or acquire any such security, which
transaction does not result in an adjustment to the
Conversion Price pursuant to the foregoing provisions of this
Section 9, the Board of Directors of the Company may
consider, but shall be under no legal obligation to consider,
whether such action is of such a nature that an adjustment to
the Conversion Price should equitably be made in respect of
such transaction. If in such case the Board of Directors of
the Company determines that an adjustment to the Conversion
Price should be made, an adjustment shall be made effective
as of such date, as determined by the Board of Directors of
the Company. The determination of the Board of Directors of
the Company as to whether an adjustment to the Conversion
Price should be made pursuant to the foregoing provisions of
this paragraph 9(F), and, if so, as to what adjustment should
be made and when, shall be final and binding on the Company
and all stockholders of the Company. Without limiting the
foregoing, the Company shall be entitled to make such
additional adjustments in the Conversion Price, in addition
to those required by the foregoing provisions of this Section
9, as shall be necessary in order that any dividend or
distribution in shares of capital stock of the Company,
subdivision, reclassification or combination of shares of
stock of the Company or any recapitalization of the Company


                            -32-

   78

or other event shall not be taxable to holders of the Common
Stock.

          (G) For purposes of this Resolution, the following
definitions shall apply:

          "Extraordinary Distribution" shall mean any dividend
or other distribution (i) of cash, including for this purpose
regular quarterly cash dividends declared and paid by the
Company, and (ii) of any shares of capital stock of the Company
(other than shares of Common Stock referred to in clause (i) of
paragraph (A) of this Section 9), other securities of the
Company (other than rights or warrants of the type referred to
in paragraph (B) of this Section 9), evidence of indebtedness
of the Company or any other person or any other property
(including shares of any subsidiary of the Company), or any
combination thereof, each as valued at Fair Market Value.

          "Fair Market Value" shall mean (a) as to cash, the
 amount of cash, and (b) as to shares of Common Stock or any
 other class of capital stock or securities of the Company or
 any other issuer which are publicly traded, the average of the
 Current Market Prices (as hereinafter defined) of such shares
 or securities for each day of the Adjustment Period (as
 hereinafter defined). "Current Market Price" of publicly
 traded shares of Common Stock or any other class of capital
 stock or other security of the Company or any other issuer for
 a day shall mean the last reported sales price, regular way,


                              -33-

   79

or, in case no sale takes place on such day, the average of
the reported closing bid and asked prices, regular way, in
either case as reported on the New York Stock Exchange
Composite Tape or, if such security is not listed or admitted
to trading on the New York Stock Exchange, on the principal
national securities exchange on which such security is listed
or admitted to trading, or if not listed or admitted to
trading on any national securities exchange, on the NASDAQ
National Market System or, if such security is not quoted on
such National Market System, the average of the closing bid
and asked prices on such day in the over-the-counter market
as reported by NASDAQ or, if bid and asked prices for such
security on such day shall not have been reported through
NASDAQ, the average of the bid and asked prices for such day
as furnished by any New York Stock Exchange member firm
regularly making a market in such security selected for such
purpose by the Board of Directors of the Company or a
committee thereof on each trading day during the Adjustment
Period. "Adjustment Period" shall mean the period of five
(5) consecutive trading days, selected by the Board of
Directors of the Company or a committee thereof, during the
20 trading days preceding, and including, the date as of
which the Fair Market Value of a security is to be
determined. The "Fair Market Value" of any security which is
not publicly traded or of any other property shall mean the

                           -34-

   80

fair value thereof as determined by an independent investment
banking or appraisal firm experienced in the valuation of
such securities or property selected in good faith by the
Board of Directors of the Company or a committee thereof, or,
if no such investment banking or appraisal firm is in the
good faith judgment of the Board of Directors or such
committee available to make such determination, as determined
in good faith by the Board of Directors of the Company or
such committee.

          "Pro Rata Repurchase" shall mean any purchase of
shares of Common Stock by the Company or any subsidiary
thereof, whether for cash, shares of capital stock of the
Company, other securities of the Company, evidences of
indebtedness of the Company or any other person or any other
property (including shares of a subsidiary of the Company),
or any combination thereof, pursuant to any tender offer or
exchange offer subject to Section 13(a) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), or any
successor provision of law.

          (H) Whenever an adjustment to the Conversion Price
and the related voting rights of the Series B Preferred Stock
is required pursuant to this Resolution, the Company shall
forthwith place on file with the transfer agent for the
Common Stock and the Series B Preferred Stock if there be
one, and with the Secretary of the Company, a statement

                            -35-

   81

signed by two officers of the Company stating the adjusted
Conversion Price determined as provided herein and the
resulting conversion ratio, and the voting rights (as
appropriately adjusted), of the Series B Preferred Stock.
Such statement shall set forth in reasonable detail such
facts as shall be necessary to show the reason and the manner
of computing such adjustment, including any determination of
Fair Market Value involved in such computation. Promptly
after each adjustment to the Conversion Price and the related
voting rights of the Series B Preferred Stock, the Company
shall mail a notice thereof and of the then prevailing
conversion ratio to each holder of shares of Series B
Preferred Stock.

          Section 10.   Ranking; Retirement of Shares.
          -------       -----------------------------

          (A) The Series B Preferred Stock shall rank senior
to the Series A Junior Participating Preferred Stock and the
Common Stock as to the payment of dividends and the
distribution of assets on liquidation, dissolution and
winding-up of the Company, and, unless otherwise provided in
the Restated Certificate of Incorporation of the Company, as
amended, or a Certificate of Designations relating to a
subsequent series of Preferred Stock, $1.00 par value, of the
Company, the Series B Preferred Stock shall rank junior to
all other series of the Company's Preferred Stock, $1.00 par

                            -36-

   82

value, as to the payment of dividends and the distribution of
assets on liquidation, dissolution or winding-up.

        (B) Any shares of Series B Preferred Stock
acquired by the Company by reason of the conversion or
redemption of such shares as provided by this Resolution, or
otherwise so acquired, shall be retired as shares of Series B
Preferred Stock and restored to the status of authorized but
unissued shares of Preferred Stock, $1.00 par value, of the
Company, undesignated as to series, and may thereafter be
reissued as part of a new series of such Preferred Stock as
permitted by law.

          Section 11.    Miscellaneous.
          ----------     -------------

          (A) All notices referred to herein shall be in
writing, and all notices hereunder shall be deemed to have
been given upon the earlier of receipt thereof or three (3)
business days after the mailing thereof if sent by registered
mail (unless first-class mail shall be specifically permitted
for such notice under the terms of this Resolution) with
postage prepaid, addressed: (i) if to the Company, to its
office at 950 Winter Street, Waltham, Massachusetts 02254 or
to the transfer agent for the Series B Preferred Stock, or
other agent of the Company designated as permitted by this
Resolution, or (ii) if to any holder of the Series B
Preferred Stock or Common Stock, as the case may be, to such
holder at the address of such holder as listed in the stock

                           -37-

   83

record books of the Company (which may include the records of
any transfer agent for the Series B Preferred Stock or Common
Stock, as the case may be) or (iii) to such other address as
the Company or any such holder, as the case may be, shall
have designated by notice similarly given.

          (B) The term "Common Stock" as used in this
Resolution means the Company's Common Stock of $1.00 par
value, as the same exists at the date of filing of a
Certificate of Designations relating to Series B Preferred
Stock or any other class of stock resulting from successive
changes or reclassifications of such Common Stock consisting
solely of changes in par value, or from par value to no par
value, or from no par value to par value. In the event that,
at any time as a result of an adjustment made pursuant to
Section 9 of this Resolution, the holder of any share of
Series B Preferred Stock upon thereafter surrendering such
shares for conversion shall become entitled to receive any
shares or other securities of the Company other than shares
of Common Stock, the Conversion Price in respect of such
other shares or securities so receivable upon conversion of
shares of Series B Preferred Stock shall thereafter be
adjusted, and shall be subject to further adjustment from
time to time, in a manner and on terms as nearly equivalent
as practicable to the provisions with respect to Common Stock
contained in Section 9 hereof, and the provisions of Sections

                          -38-

   84

1 through 8 and 10 and 11 of this Resolution with respect to
the Common Stock shall apply on like or similar terms to any
such other shares or securities.

           (C) The Company shall pay any and all stock
transfer and documentary stamp taxes that may be payable in
respect of any issuance or delivery of shares of Series B
Preferred Stock or shares of Common Stock or other securities
issued on account of Series B Preferred Stock pursuant hereto
or certificates representing such shares or securities. The
Company shall not, however, be required to pay any such tax
which may be payable in respect of any transfer involved in
the issuance or delivery of shares of Series B Preferred
Stock or Common Stock or other securities in a name other
than that in which the shares of Series B Preferred Stock
with respect to which such shares or other securities are
issued or delivered were registered, or in respect of any
payment to any person with respect to any such shares or
securities other than a payment to the registered holder
thereof, and shall not be required to make any such issuance,
delivery or payment unless and until the person otherwise
entitled to such issuance, delivery or payment has paid to
the Company the amount of any such tax or has established, to
the satisfaction of the Company, that such tax has been paid
or is not payable.


                           -39-

   85

          (D) In the event that a holder of shares of Series
B Preferred Stock shall not by written notice designate the
name in which shares of Common Stock to be issued upon
conversion of such shares should be registered or to whom
payment upon redemption of shares of Series B Preferred Stock
should be made or the address to which the certificate or
certificates representing such shares, or such payment,
should be sent, the Company shall be entitled to register
such shares, and make such payment, in the name of the holder
of such Series B Preferred Stock as shown on the records of
the Company and to send the certificate or certificates
representing such shares, or such payment, to the address of
such holder shown on the records of the Company.

          (E) Unless otherwise provided in the Restated
Certificate of Incorporation, as amended, of the Company, all
payments in the form of dividends, distributions on voluntary
or involuntary dissolution, liquidation or winding-up or
otherwise made upon the shares of Series B Preferred Stock
and any other stock ranking on a parity with the Series B
Preferred Stock with respect to such dividends or
distributions shall be made pro rata, so that amounts paid
per share on the Series B Preferred Stock and such other
stock shall in all cases bear to each other the same ratio
that the required dividends, distributions or payments, as
the case may be, then payable per share on the shares of the

                            -40-

   86

Series B Preferred Stock and such other stock bear to each
other.

          (F) The Company may appoint, and from time to time
discharge and change, a transfer agent for the Series B
Preferred Stock. Upon any such appointment or discharge of a
transfer agent, the Company shall send notice thereof by
first-class mail, postage prepaid, to each holder of record
of Series B Preferred Stock.

          IN WITNESS WHEREOF, I have executed and subscribed
this Certificate of Designations and do affirm the foregoing
as true under the penalties of perjury this 17th day of
November, 1988.


                                /s/ Samuel W. Bodman   
                                ----------------------
                                Samuel W. Bodman
                                Chairman of the Board

ATTEST:

/s/ Charles Gerlinger   
- ------------------------
Charles Gerlinger
Secretary


                               -41-
   87
                                                                 EXHIBIT 3(a)

              AMENDED CERTIFICATE OF DESIGNATION, PREFERENCES AND
                    RIGHTS OF SERIES A JUNIOR PARTICIPATING
                      PREFERRED STOCK OF CABOT CORPORATION

                            (Pursuant to Section 151
            of the General Corporation Law of the State of Delaware)

                  We, Kennett F. Burnes, President, and Charles D. Gerlinger,
Secretary of Cabot Corporation (the "Corporation"), a corporation organized and
existing under the General Corporation Law of the State of Delaware, in
accordance with the provisions of Section 103 thereof, DO HEREBY CERTIFY as
follows:

                  That pursuant to the authority conferred upon the Board of
Directors by the Certificate of Incorporation of the said Corporation, said
Board of Directors on November 10, 1995, voted to create a series of 1,000,000
shares of Preferred Stock designated as Series A Junior Participating Preferred
Stock:

                  VOTED, that pursuant to the authority granted to and vested in
the Board of Directors of this Corporation in accordance with the provisions of
the Corporation's Certificate of Incorporation and Section 151(g) of the General
Corporation Law of the State of Delaware, the Board of Directors hereby approves
and adopts an amendment to the Certificate of Designation, Preferences and
Rights of the Series A Junior Participating Preferred Stock of Cabot
Corporation, which Certificate is hereby amended in its entirety, and hereby
states the designation and number of shares, and fixes the relative rights,
preferences and limitations thereof (in addition to the provisions set forth in
the Corporation's Certificate of Incorporation which are applicable to the
Preferred Stock of all classes and series) as follows:

                  Section 1. Designation and Amount. There shall be a series of
Preferred Stock, par value $1.00 per share, of the Corporation which shall be
designated as "Series A Junior Participating Preferred Stock," par value $1.00
per share, and the number of shares constituting such series shall be 1,000,000.
Such number of shares may be increased or decreased by resolution of the Board
of Directors; provided, that no decrease shall reduce the number of shares of
Series A Junior Participating Preferred Stock to a number less than that of the
shares then outstanding plus the number of shares issuable upon exercise of
outstanding rights, options or warrants or upon conversion of outstanding
securities issued by the Corporation.

                  Section 2.  Dividends and Distributions.

                  (A) Subject to the prior and superior rights of the holders of
any shares of any series of Preferred Stock ranking prior and superior to the
Series A Junior Participating Preferred Stock with respect to dividends, the
holders of shares of Series A
   88
Junior Participating Preferred Stock in preference to the holders of shares of
Common Stock, par value $1.00 per share (the "Common Stock"), of the Corporation
and any other junior stock, shall be entitled to receive, when, as and if
declared by the Board of Directors out of funds legally available for the
purpose, quarterly dividends payable in cash on the last day of each fiscal
quarter of the Corporation in each year or such other dates as the Board of
Directors of the Corporation shall approve (each such date being referred to
herein as a "Quarterly Dividend Payment Date"), commencing on the first
Quarterly Dividend Payment Date after the first issuance of a share or fraction
of a share of Series A Junior Participating Preferred Stock in an amount per
share (rounded to the nearest cent) equal to the greater of (a) $18.00 or (b)
subject to the provision for adjustment hereinafter set forth, 100 times the
aggregate per share amount of all cash dividends, and 100 times the aggregate
per share amount (payable in kind) of all non-cash dividends or other
distributions other than a dividend payable in shares of Common Stock or a
subdivision of the outstanding shares of Common Stock (by reclassification or
otherwise), declared on the Common Stock since the immediately preceding
Quarterly Dividend Payment Date, or, with respect to the first Quarterly
Dividend Payment Date, since the first issuance of any share or fraction of a
share of Series A Junior Participating Preferred Stock. In the event the
Corporation shall at any time after November 24, 1995 (the "Rights Declaration
Date") (i) declare any dividend on Common Stock payable in shares of Common
Stock, (ii) subdivide (by a stock split or otherwise) the outstanding Common
Stock, or (iii) combine (by a reverse stock split or otherwise) the outstanding
Common Stock into a smaller number of shares, then in each such case the amount
to which holders of shares of Series A Junior Participating Preferred Stock were
entitled immediately prior to such event under clause (b) of the preceding
sentence shall be adjusted by multiplying such amount by a fraction the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

                  (B) The Corporation shall declare a dividend or distribution
on the Series A Junior Participating Preferred Stock as provided in paragraph
(A) above at the time it declares a dividend or distribution on the Common Stock
(other than a dividend payable in shares of Common Stock); provided that, in the
event no dividend or distribution shall have been declared on the Common Stock
during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $18.00 per share on
the Series A Junior Participating Preferred Stock shall nevertheless be payable
on such subsequent Quarterly Dividend Payment Date.

                  (C) So long as any shares of the Series A Junior Participating
Preferred Stock are outstanding, no dividends or other distributions shall be
declared, paid or distributed, or set aside for payment or distribution, on the
Common Stock unless, in each

                                      -2-
   89
case, the dividend required by this Section 2 to be declared on the Series A
Junior Participating Preferred Stock shall have been declared.

                  (D) The holders of the shares of the Series A Junior
Participating Preferred Stock shall not be entitled to receive any dividends or
other distributions except as provided herein.

                  (E) Dividends shall begin to accrue and be cumulative on
outstanding shares of Series A Junior Participating Preferred Stock from the
Quarterly Dividend Payment Date next preceding the date of issue of such shares
of Series A Junior Participating Preferred Stock unless the date of issue of
such shares is prior to the record date for the first Quarterly Dividend Payment
Date, in which case dividends on such shares shall begin to accrue from the date
of issue of such shares, or unless the date of issue is a Quarterly Dividend
Payment Date or is a date after the record date for the determination of holders
of shares of Series A Junior Participating Preferred Stock entitled to receive a
quarterly dividend and before such Quarterly Dividend Payment Date in either of
which events such dividends shall begin to accrue and be cumulative from such
Quarterly Dividend Payment Date. Accrued but unpaid dividends shall not bear
interest. Dividends paid on the shares of Series A Junior Participating
Preferred Stock in an amount less than the total of such dividends at the time
accrued and payable on such shares shall be allocated pro rata on a
share-by-share basis among all such shares at the time outstanding. The Board of
Directors may fix a record date for the determination of holders of shares of
Series A Junior Participating Preferred Stock entitled to receive payment of a
dividend or distribution declared thereon, which record date shall be no more
than 60 days prior to the date fixed for the payment thereof.

                  Section 3.  Voting Rights.  The holders of shares of Series A
Junior Participating Preferred Stock shall have the following voting rights:

                  (A) Subject to the provision for adjustment hereinafter set
forth, each share of Series A Junior Participating Preferred Stock shall entitle
the holder thereof to 100 votes on all matters submitted to a vote of the
stockholders of the Corporation. In the event the Corporation shall at any time
after the Rights Declaration Date (i) declare any dividend on Common Stock
payable in shares of Common Stock, (ii) subdivide (by a stock split or
otherwise) the outstanding Common Stock, or (iii) combine (by a reverse stock
split or otherwise) the outstanding Common Stock into a smaller number of
shares, then in each such case the number of votes per share to which holders of
shares of Series A Junior Participating Preferred Stock were entitled
immediately prior to such event shall be adjusted by multiplying such number by
a fraction the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

                                      -3-
   90
                  (B) Except as otherwise provided herein or by law, the holders
of shares of Series A Junior Participating Preferred Stock and the holders of
shares of Common Stock shall vote together as one class on all matters submitted
to a vote of stockholders of the Corporation.

                  (C)      (i) If at any time dividends on any Series A Junior
Participating Preferred Stock shall be in arrears in an amount equal to at least
six (6) full quarterly dividends (whether or not declared and whether or not
consecutive) thereon, the occurrence of such contingency shall mark the
beginning of a period (herein called a "default period") which shall extend
until such time when all accrued and unpaid dividends for all previous quarterly
dividend periods and for the current quarterly dividend period on all shares of
Series A Junior Participating Preferred Stock then outstanding shall have been
declared and paid or set apart for payment. During each default period, all
holders of Preferred Stock (including holders of the Series A Junior
Participating Preferred Stock) with dividends in arrears in an amount equal to
at least six (6) full quarterly dividends (whether or not declared and whether
or not consecutive) thereon, voting as a class, irrespective of series, shall
have the right to elect two (2) Directors.

                           (ii) During any default period, such voting right of
the holders of Series A Junior Participating Preferred Stock may be exercised
initially at a special meeting called pursuant to subparagraph (iii) of this
Section 3(C) or at any annual meeting of stockholders, and thereafter at annual
meetings of stockholders, provided that neither such voting right nor the right
of the holders of any other series of Preferred Stock, if any, to increase, in
certain cases, the authorized number of Directors shall be exercised unless the
holders of one-third (1/3) in number of shares of Preferred Stock outstanding
shall be present in person or by proxy. The absence of a quorum of the holders
of Common Stock shall not affect the exercise by the holders of Preferred Stock
of such voting right. At any meeting at which the holders of Preferred Stock
shall exercise such voting right initially during an existing default period,
they shall have the right, voting as a class, to elect Directors to fill such
vacancies, if any, in the Board of Directors as may then exist up to two (2)
Directors or, if such right is exercised at an annual meeting, to elect two (2)
Directors. If the number which may be so elected at any special meeting does not
amount to the required number, the holders of the Preferred Stock shall have the
right to make such increase in the number of Directors as shall be necessary to
permit the election by them of the required number. After the holders of the
Preferred Stock shall have exercised their right to elect Directors in any
default period and during the continuance of such period, the number of
directors shall not be increased or decreased except by vote of the holders of
Preferred Stock as herein provided or pursuant to the rights of any equity
securities ranking senior to or pari passu with the Series A Junior
Participating Preferred Stock.

                                      -4-
   91
                           (iii) Unless the holders of Preferred Stock shall,
during an existing default period, have previously exercised their right to
elect Directors, the Board of Directors may order, or any stockholder or
stockholders owning in the aggregate not less than ten percent (10%) of the
total number of Preferred Stock outstanding, irrespective of series, may
request, the calling of a special meeting of the holders of Preferred Stock,
which meeting shall thereupon be called by the Chairman of the Board or the
President of the Corporation. Notice of such meeting and of any annual meeting
at which holders of Preferred Stock are entitled to vote pursuant to this
paragraph (C)(iii) shall be given to each holder of record of Preferred Stock by
mailing a copy of such notice to him at his last address as the same appears on
the books of the Corporation. Such meeting shall be called for a time not
earlier than 10 days and not later than 60 days after such order or request or
in default of the calling of such meeting within 60 days after such order or
request, such meeting may be called on similar notice by any stockholder or
stockholders owning in the aggregate not less than ten percent (10%) of the
total number of shares of Preferred Stock outstanding. Notwithstanding the
provisions of this paragraph (C)(iii), no such special meeting shall be called
during the period within 60 days immediately preceding the date fixed for the
next annual meeting of the stockholders.

                           (iv)  In any default period, the holders of Common
Stock, and other classes of stock of the Corporation if applicable, shall
continue to be entitled to elect the whole number of Directors until the holders
of Preferred Stock shall have exercised their right to elect two (2) Directors
voting as a class, after the exercise of which right (x) the Directors so
elected by the holders of Preferred Stock shall continue in office until their
successors shall have been elected by such holders or until the expiration of
the default period, and (y) any vacancy in the Board of Directors may (except as
provided in paragraph (C)(ii) of this Section 3) be filled by a vote of a
majority of the remaining Directors theretofore elected by the holders of the
class of stock which elected the Director whose office shall become vacant.
References in this paragraph (C) to Directors elected by the holders of a
particular class of stock shall include Directors elected by such Directors to
fill vacancies as provided in clause (y) of the foregoing sentence.

                           (v)   Immediately upon the expiration of a default
period, (x) the right of the holders of Preferred Stock as a class to elect
Directors shall cease, (y) the term of any Directors elected by the holders of
Preferred Stock as a class shall terminate, and (z) the number of Directors
shall be such number as may be provided for in the Certificate of Incorporation
or By-laws irrespective of any increase made pursuant to the provisions of
paragraph (C)(ii) of this Section 3 (such number being subject, however, to
change thereafter in any manner provided by law or in the Certificate of
Incorporation or By-laws). Any vacancies in the Board of Directors effected by
the provisions of clauses (y) and (z) in the preceding sentence may be filled by
a majority of the remaining Directors.

                                      -5-
   92
                  (D) Except as set forth herein, holders of Series A Junior
Participating Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

                  Section 4.  Certain Restrictions.

                  (A) Whenever quarterly dividends or other dividends or
distributions payable on the Series A Junior Participating Preferred Stock as
provided in Section 2 are in arrears, thereafter and until all accrued and
unpaid dividends and distributions, whether or not declared, on shares of Series
A Junior Participating Preferred Stock outstanding shall have been paid in full,
the Corporation shall not:

                           (i)   Declare or pay dividends on, make any other
distributions on, or redeem or purchase or otherwise acquire for consideration
any shares of stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series A Junior Participating Preferred Stock;

                           (ii)  Declare or pay dividends on or make any other
distributions on any shares of stock ranking on a parity (either as to dividends
or upon liquidation, dissolution or winding up) with the Series A Junior
Participating Preferred Stock except dividends paid ratably on the Series A
Junior Participating Preferred Stock and all such parity stock on which
dividends are payable or in arrears in proportion to the total amounts to which
the holders of all such shares are then entitled;

                           (iii) Redeem or purchase or otherwise acquire for
consideration shares of any stock ranking on a parity (either as to dividends or
upon liquidation, dissolution or winding up) with the Series A Junior
Participating Preferred Stock provided that the Corporation may at any time
redeem, purchase or otherwise acquire shares of any such parity stock in
exchange for shares of any stock of the Corporation ranking junior (either as to
dividends or upon dissolution, liquidation or winding up) to the Series A Junior
Participating Preferred Stock; or

                           (iv)  Purchase or otherwise acquire for consideration
any shares of Series A Junior Participating Preferred Stock or any shares of
stock ranking on a parity with the Series A Junior Participating Junior
Preferred Stock except in accordance with a purchase offer made in writing or by
publication (as determined by the Board of Directors) to all holders of such
shares upon such terms as the Board of Directors, after consideration of the
respective annual dividend rates and other relative rights and preferences of
the respective series and classes, shall determine in good faith will result in
fair and equitable treatment among the respective series or classes.

                                      -6-
   93
                  (B) The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (A) of
this Section 4, purchase or otherwise acquire such shares at such time and in
such manner.

                  Section 5. Reacquired Shares. Any shares of Series A Junior
Participating Preferred Stock purchased or otherwise acquired by the Corporation
in any manner whatsoever shall be retired and cancelled promptly after the
acquisition thereof. All such shares shall upon their cancellation become
authorized but unissued shares of Preferred Stock and may be reissued as part of
a new series of Preferred Stock to be created by resolution or resolutions of
the Board of Directors, subject to the conditions and restrictions on issuance
set forth herein.

                  Section 6. Liquidation, Dissolution or Winding Up.

                  (A) Upon any liquidation (voluntary or otherwise), dissolution
or winding up of the Corporation, no distribution shall be made to the holders
of shares of stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series A Junior Participating Preferred Stock
unless, prior thereto, the holders of shares of Series A Junior Participating
Preferred Stock shall have received per share, the amount of $18.00, plus an
amount equal to accrued and unpaid dividends and distributions thereon, whether
or not declared, to the date of such payment (the "Series A Liquidation
Preference"). Following the payment of the full amount of the Series A
Liquidation Preference, no additional distributions shall be made to the holders
of shares of Series A Junior Participating Preferred Stock unless, prior
thereto, the holders of shares of Common Stock shall have received an amount per
share (the "Common Adjustment") equal to the quotient obtained by dividing (i)
the Series A Liquidation Preference by (ii) 100 (as appropriately adjusted as
set forth in paragraph (C) below to reflect such events as stock splits, stock
dividends and recapitalizations with respect to the Common Stock) (such number
in clause (ii), the "Adjustment Number"). Following the payment of the full
amount of the Series A Liquidation Preference and the Common Adjustment in
respect of all outstanding shares of Series A Junior Participating Preferred
Stock and Common Stock, respectively, holders of Series A Junior Participating
Preferred Stock and holders of shares of Common Stock shall receive their
ratable and proportionate share of the remaining assets to be distributed in the
ratio of the Adjustment Number to 1 with respect to such Preferred Stock and
Common Stock, on a per share basis, respectively.

                  (B) In the event there are not sufficient assets available to
permit payment in full of the Series A Liquidation Preference and the
liquidation preferences of all other series of Preferred Stock, if any, which
rank on a parity with the Series A Junior Participating Preferred Stock, then
such remaining assets shall be distributed ratably to the holders of such parity
shares in proportion to their respective liquidation preferences.

                                      -7-
   94
In the event there are not sufficient assets available to permit payment in full
of the Common Adjustment, then such remaining assets shall be distributed
ratably to the holders of Common Stock.

                  (C) In the event the Corporation shall at any time after the
Rights Declaration Date (i) declare any dividend on Common Stock payable in
shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii)
combine the outstanding Common Stock into a smaller number of shares, then in
each case the Adjustment Number in effect immediately prior to such event shall
be adjusted by multiplying such Adjustment Number by a fraction the numerator of
which is the number of shares of Common Stock outstanding immediately after such
event and the denominator of which is the number of shares of Common Stock that
were outstanding immediately prior to such event.

                  Section 7. Consolidation, Merger, etc. If the Corporation
shall enter into any consolidation, merger, combination or other transaction in
which the shares of Common Stock are exchanged for or changed into other stock
or securities, cash and/or any other property, then in any such event the shares
of Series A Junior Participating Preferred Stock shall at the same time be
similarly exchanged or changed in an amount per share (subject to the provision
for adjustment hereinafter set forth) equal to the Adjustment Number times the
aggregate amount of stock, securities, cash and/or any other property (payable
in kind), as the case may be, into which or for which each share of Common Stock
is changed or exchanged.

                  Section 8.  No Redemption.  The shares of Series A Junior
Participating Preferred Stock shall not be redeemable.

                  Section 9. Ranking. The Series A Junior Participating
Preferred Stock shall rank junior to all other series of the Corporation's
Preferred Stock as to the payment of dividends and the distribution of assets,
unless the terms of any such series shall provide otherwise.

                  Section 10. Fractional Shares. Series A Junior Participating
Preferred Stock may be issued in fractions of a share which shall entitle the
holder, in proportion to such holder's fractional shares, to exercise voting
rights, receive dividends, participate in distributions and to have the benefit
of all other rights of holders of Series A Junior Participating Preferred Stock.

                  Section 11. Amendment. The Certificate of Incorporation of the
Corporation shall not be further amended in any manner which would materially
alter or change the powers, preferences or special rights of the Series A Junior
Participating Preferred Stock so as to affect them adversely without the
affirmative vote of the holders

                                      -8-
   95
of a majority or more of the outstanding shares of Series A Junior Participating
Preferred Stock, voting separately as a class.

                  Section 12. Effective Date. This Amended Certificate of
Designation, Preferences and Rights of Series A Junior Participating Preferred
Stock of Cabot Corporation shall be effective at 5:00 P.M., Eastern Standard
Time, on November 24, 1995.

                  IN WITNESS WHEREOF, I have executed and subscribed this
Certificate and do affirm the foregoing as true under penalties of perjury this
10th day of November, 1995.

                                                     By:/s/ Kennett F. Burnes
                                                        ------------------------
                                                        Kennett F. Burnes
                                                        President

Attest:

/s/ Charles D. Gerlinger
- --------------------------

Charles D. Gerlinger
Secretary

                                      -9-