1
                                 [FACE OF NOTE]

UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR ONE OR MORE NOTES IN
CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, 55 WATER STREET, NEW YORK, NEW YORK (THE
"DEPOSITARY"), TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY
TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR
ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR
DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITARY TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND UNLESS ANY NOTE ISSUED UPON SUCH TRANSFER OR EXCHANGE IS REGISTERED
IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITARY AND ANY SUCH PAYMENT IS MADE TO CEDE & CO., ANY
TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON
IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
HEREIN.


REGISTERED                                                  PRINCIPAL AMOUNT
No. 001                                                     U.S. $100,000,000

CUSIP NO. 427056AQ9

                              HERCULES INCORPORATED
                          6.15% NOTE DUE AUGUST 1, 2000


                  HERCULES INCORPORATED, a Delaware corporation (the
"Company"), for value received promises to pay to

                                   CEDE & CO.
                        c/o THE DEPOSITORY TRUST COMPANY
                                 55 WATER STREET
                            NEW YORK, NEW YORK 10041

, or registered assigns, the principal sum of

                           ONE HUNDRED MILLION DOLLARS

on August 1, 2000 (the "Maturity Date"), and to pay interest thereon at the
interest rate per annum of 6.15%, semi-annually in arrears on February 1 and
August 1 of each year, commencing February 1, 1998 (each, an "Interest Payment
Date"), to the Holder of this Note as of the close of business on the Regular
Record Date, as defined below, with respect to such Interest Payment Date, until
the principal hereof is paid or duly made available for payment.
   2
                  Interest payments for this Note will be computed on the basis
of a 360-day year of twelve 30-day months. Interest payable on this Note on any
Interest Payment Date will include interest accrued from and including the
immediately preceding Interest Payment Date in respect of which interest has
been paid or duly provided for (or from and including August 4, 1997, if no
interest has been paid or duly provided for with respect to this Note) to but
excluding such Interest Payment Date. If any Interest Payment Date or the
Maturity Date falls on a day that is not a Business Day, as defined below, the
required payment of principal and interest with respect to such Interest Payment
Date or Maturity Date, as the case may be, will be paid on the next succeeding
Business Day with the same force and effect as if it were paid on the date such
payment was due, and no interest shall accrue on the amount so payable for the
period from and after such Interest Payment Date or Maturity Date, as the case
may be. "Business Day" means any day other than Saturday, Sunday or other day on
which banks are authorized or required to be closed in The City of New York or
Wilmington, Delaware.

                  The interest so payable, and punctually paid or duly provided
for, on any Interest Payment Date will be paid to the person in whose name this
Note is registered in the Security Register of the Company as of the close of
business on the "Regular Record Date" for such interest payment, which shall be
the January 15 (whether or not a Business Day) preceding the February 1 Interest
Payment Date or the July 15 (whether or not a Business Day) preceding the August
1 Interest Payment Date, as the case may be.

                  The principal of this Note payable on the Maturity Date will
be paid against presentation of this Note at the Corporate Trust Office of the
Trustee maintained for that purpose in the Borough of Manhattan, The City of New
York, in such coin or currency of the United States of America as at the time of
payment is legal tender for the payment of public and private debts.

                  All payments of principal and interest in respect of this Note
will be made by the Company in immediately available funds.

                  Reference is hereby made to the further provisions of this
Note set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

                  Unless the Certificate of Authentication hereon has been
executed by the Trustee under the Indenture, as each such term is defined below,
directly or through an Authenticating Agent, by the manual signature of one of
its authorized


                                       2
   3
signatories, this Note shall not be entitled to any benefit under the Indenture
or be valid or obligatory for any purpose.


                                       3
   4
                  IN WITNESS WHEREOF, the Company has caused this instrument to
be duly executed, manually or in facsimile, and a facsimile of its corporate
seal to be imprinted hereon.

Dated: 



                                    HERCULES INCORPORATED


[SEAL]
                                    By:
                                       ----------------------------------------
                                       Name:
                                       Title:



                                    By:
                                       ----------------------------------------
                                       Name:
                                       Title:



Attest:                             By:
                                       ----------------------------------------
                                       Name:
                                       Title:



TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Securities issued 
under the within-mentioned Indenture.

PNC BANK, DELAWARE,
as Trustee



By:
   ----------------------------------
   Authorized Signatory

                                       4
   5
                                [REVERSE OF NOTE]

                              HERCULES INCORPORATED

                          6.15% NOTE DUE AUGUST 1, 2000


                  This Note is one of the duly authorized securities
(collectively, the "Securities") of the Company to be issued under an Indenture
between the Company and PNC Bank, Delaware, as successor trustee (herein called
the "Trustee", which term includes any successor trustee thereunder), dated as
of May 15, 1993 (the "Indenture"), to which Indenture and all indentures
supplemental thereto reference is hereby made for a statement of the respective
rights, limitations of rights, duties, obligations and immunities thereunder of
the Company, the Trustee and the Holders of the Securities and the terms upon
which the Securities are, and are to be, authenticated and delivered. This Note
is one of the duly authorized series of Securities designated as "6.15% Notes
due August 1, 2000" (collectively, the "Notes"), and the aggregate principal
amount of Notes to be issued under such series is limited to $100,000,000
(except for Notes authenticated and delivered upon transfer of, or in exchange
for, or in lieu of other Notes). All terms used but not defined or specified in
this Note shall have the meanings assigned to such terms in the Indenture.

                  This Note will not be subject to redemption prior to the
Maturity Date.

                  If an Event of Default with respect to the Notes shall occur
and be continuing, the Trustee or the Holders of not less than 25% in aggregate
principal amount of the Notes at the time Outstanding may declare the principal
of all Notes due and payable in the manner and with the effect provided in the
Indenture.

                  The Indenture permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Holders of the Securities of
each series to be affected under the Indenture at any time by the Company and
the Trustee with the consent of the Holders of a majority in aggregate principal
amount of the Securities of each series adversely affected thereby at the time
Outstanding (voting as one class). The Indenture also contains provisions
permitting the Holders of a majority in aggregate principal amount of the
Securities of any series affected and at the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive compliance by the Company
with certain provisions of the Indenture and certain past defaults under the
Indenture and their consequences. Any such consent or waiver by the Holder of
this Note shall be


                                       5
   6
conclusive and binding upon such Holder and upon all future Holders of this Note
and of any Note issued upon the registration of transfer hereof or in exchange
hereof or in lieu hereof, whether or not notation of such consent or waiver is
made upon this Note.

                  No reference herein to the Indenture and no provision of this
Note or of the Indenture shall alter or impair the obligation of the Company,
which is absolute and unconditional, to pay the principal of and interest on
this Note at the time, place and rate, and in the coin or currency, herein
prescribed.

                  As provided in the Indenture, and subject to certain
limitations herein and therein set forth, the transfer of this Note may be
registered in the Security Register of the Company upon surrender of this Note
for registration of transfer at the office or agency of the Company in the
Borough of Manhattan, The City of New York, duly endorsed by, or accompanied by
this Note and a written instrument of transfer in form satisfactory to the
Company duly executed by, the Holder hereof or by his attorney duly authorized
in writing and thereupon one or more new Notes, in authorized denominations,
having the same terms and conditions and for the same aggregate principal
amount, will be issued to the designated transferee or transferees.

                  As provided in the Indenture, and subject to certain
limitations herein and therein set forth, this Note is exchangeable for a like
aggregate principal amount of Notes having the same terms and conditions, in
authorized denominations, as requested by the Holder surrendering the same.

                  If (i) the Depositary is at any time unwilling or unable to
continue as depositary and a successor depositary is not appointed by the
Company within 90 days, (ii) the Company at any time determines not to have
Securities represented by this Note, (iii) the Company defaults on the payment
of principal or interest with respect to this Note or (iv) an Event of Default
has occurred and is continuing with respect to this Note, then the Company will
issue Notes in definitive form in exchange for this Note to beneficial owners of
interests therein equal in principal amount to such interest and will have such
Notes registered in their names. Notes so issued in definitive form will be
issued in denominations of $1,000 or any integral multiple thereof and will be
issued in registered form only, without coupons.

                  No service charge will be made for any registration of
transfer or exchange of Notes, but the Company may require payment of a sum
sufficient to cover any tax or other governmental charge payable in connection
therewith.
                                       6
   7

                  The Notes are issuable only in fully registered form without
coupons in denominations of $1,000 and any integral multiple in excess thereof.

                  Prior to due presentment of this Note for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Note is registered as the owner hereof
for all purposes, whether or not this Note be overdue, and neither the Company,
the Trustee nor any such agent shall be affected by notice to the contrary.

                  The Indenture and the Notes shall be governed by, and
construed in accordance with, the laws of the State of New York without regard
to conflict of law principles thereof.

                                       7
   8
                                  ABBREVIATIONS


                  The following abbreviations, when used in the inscription on
the first page of this instrument, shall be construed as though they were
written out in full according to applicable laws or regulations.


                UNIF GIFT MIN ACT -- ___________________________________
                                                 (Cust)

                           Custodian ___________________________________
                                                (Minor)

                                            Under Uniform Gifts to Minors Act

                                      -----------------------------------------
                                                    (State)


TEN COM           --       as tenants in common
TEN ENT           --       as tenants by the entireties
JT TEN            --       as joint tenants with right of survivorship and
                           not as tenants in common

                  Additional abbreviations may also be used though not in the
above list.

                          ----------------------------


                                       8
   9
                                   ASSIGNMENT


                  FOR VALUE RECEIVED, the undersigned hereby sell(s),
assign(s) and transfer(s) unto




Please Insert Social Security Number or Other Identifying Number
of Assignee:


- -----------------------------------------------------------------


PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE,
OF ASSIGNEE:

- -----------------------------------------------------------------

- -----------------------------------------------------------------

- -----------------------------------------------------------------


the within Note and all rights thereunder, hereby irrevocably
constituting and appointing

- -----------------------------------------------------------------


attorney to transfer said Note on the books of the Company, with full power of
substitution in the premises.


Dated: ___________________          ______________________________
                                    NOTICE: The signature to this
                                    assignment must correspond
                                    with the name as written upon
                                    the face of this Note in every 
                                    particular, without alteration
                                    or enlargement or any change 
                                    whatsoever.

                                    SIGNATURE GUARANTEE


                                    ------------------------------

                                       9