EXHIBIT 1.2

                               CERTIFICATE OF AMENDMENT
                                          OF
                         RESTATED CERTIFICATE OF INCORPORATION
                                           
                                           
    Hach Company, 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, adopted a resolution proposing and declaring advisable the 
following amendment to the Restated Certificate of Incorporation of said 
corporation:

         RESOLVED, that the Restated Certificate of Incorporation of Hach 
Company be amended by changing the Fourth Article thereof so that, as 
amended, said Article shall be and read as follows:

         "FOURTH:  The total number of shares of all classes of capital stock 
which the Corporation shall have authority to issue is forty-five million 
(45,000,000) shares which shall be divided into two classes as follows:

         (a)  Twenty Million (20,000,000) shares of Class A Common Stock of 
the par value of one dollar ($1.00) per share; and 

         (b)  Twenty Five Million (25,000,000) shares of Common Stock of the 
par value of one dollar ($1.00) per share.  

         The Class A Common Stock and Common Stock are hereinafter 
collectively referred to as the "Common Stocks."  The designations and 
powers, preferences and rights, and the qualifications, limitations and 
restrictions thereof, of the above classes of stock shall be as follows:

    1.   RIGHTS.  Except as otherwise required by law or as otherwise 
provided in this Article Fourth, each share of Class A Common Stock and each 
share of Common Stock shall have identical powers, preferences, 
qualifications, limitations and other rights. 

    2.   DIVIDENDS.  Subject to all of the rights of any class of stock 
authorized after the effective date of this provision of Article Fourth 
ranking senior to the Common Stocks as to dividends, dividends may be paid 
upon the Class A Common Stock and the Common Stock as and when declared by 
the Board of Directors out of funds and other assets legally available for 
the payment of dividends.  If and when dividends on the Class A Common Stock 
and the Common Stock are declared and payable from time to time by the Board 
of Directors whether payable in cash, in  property or in shares of stock of 
the Corporation, the holders of the Class A Common Stock and the holders of 
the Common Stock shall be entitled to share equally, on a per share basis, in 
such dividends, except that (a) a dividend or distribution in cash or 
property on a share of Class A Common Stock may be greater than a dividend or 
distribution in cash or property on a share of Common Stock, and (b) 




dividends or other distributions payable on the Common Stocks in shares of 
any authorized class or series of capital stock of the Corporation may be 
made (i) in shares of Class A Common Stock to the holders of Class A Common 
Stock and in shares of Common Stock to the holders of Common Stock, (ii) in 
shares of Class A Common Stock to the holders of Class A Common Stock and to 
the holders of Common Stock, or (iii) in any other authorized class or series 
of capital stock to the holders of both classes of Common Stocks.

    3.   LIQUIDATION.  In the event of any liquidation, dissolution or 
winding up of the Corporation, whether voluntary or involuntary, and after 
the holders of any class of stock authorized after the effective date of this 
provision of Article Fourth ranking senior to the Common Stocks as to 
distribution of assets shall have been paid in full the amounts to which such 
holders shall be entitled, or an amount sufficient to pay the aggregate 
amount to which such holders shall be entitled shall have been set aside for 
the benefit of the holders of such stock, the remaining net assets of the 
Corporation shall be distributed pro rata to the holders of both classes of 
the Common Stocks.

    4.   MERGER AND CONSOLIDATION.  In the event of a merger or consolidation 
of the Corporation with or into another entity (whether or not the 
Corporation is the surviving entity), the holders of Class A Common Stock 
shall be entitled to received the same per share consideration as the per 
share consideration, if any, received by any holder of the Common Stock in 
such merger or consolidation. 

    5.   VOTING.

         (a) Except as otherwise expressly provided with respect to any other 
class of stock and except as otherwise may be required by law or this 
certificate, the Common Stock shall have the exclusive right to vote for the 
election of directors and for all other purposes and each holder of Common 
Stock shall be entitled to one vote for each share of Common Stock held.  
Except as expressly provided in this certificate and except as otherwise 
required by law, the Class A Common Stock shall have no voting rights. 

         (b)  The Class A Common Stock shall be entitled to vote separately 
as a class only with respect to (i) proposals to change the par value of the 
Class A Common Stock, (ii) other amendments to this certificate that alter or 
change the powers, preferences or special rights of the Class A Common Stock 
so as to affect them adversely, and (iii) such other matters as may require 
class voting under the Delaware General Corporation Law. 

         (c)  The number of authorized shares of Class A Common Stock and 
Common Stock may be increased or decreased (but not below the number of 
shares then outstanding) by the affirmative vote of the holders of a majority 
of the Common Stocks entitled to vote.

    6.   STOCK SPLITS.  The Corporation may not split, divide or combine the 
shares of either class of Common Stocks unless, at the same time, the 
Corporation splits, divides or combines, as the case may be, the shares of 
the other class of Common Stocks in the same proportion and manner. 

    7.   NO PRE-EMPTIVE RIGHTS.  No stockholder of this Corporation shall by 
reason of his holding shares of any class have any pre-emptive or 
preferential right to 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 issuance of any such shares, or such notes, 
debentures, bonds or other securities, would adversely affect the dividends 
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 of any class, either in whole or in 
part, to the existing stockholders of any class.

    8.   ISSUANCES AND REPURCHASES OF COMMON STOCKS.

         (a)  The Board of Directors shall have the power to issue and sell 
all or any part of any class of stock herein or hereafter authorized to such 
persons, firms, associations or corporations and for such consideration as 
the Board of Directors shall from time to time, it its discretion, determine, 
whether or not greater consideration could be received upon the issue or sale 
of the same number of shares of another class, and as otherwise permitted by 
law. 

         (b)  The Board of Directors shall have the power to purchase any 
class of stock herein or hereafter authorized from such persons, firms, 
associations or corporations for such consideration as the Board of Directors 
shall from time to time, in its discretion, determine, whether or not less 
consideration could be paid upon the purchase of the same number of shares of 
another class, and as otherwise permitted by law. 

         (c)  For purposes of this subsection 8 of this Article Fourth, the 
term "persons" means a natural person, company, government, or any political 
subdivision, agency or instrumentality of a government, or other entity.  

    9.   CLASS A PROTECTION PROVISIONS.

         (a)  If, after the time that this Section 9 of Article Fourth 
becomes effective (the "Effective Time"), a Person or group, each as defined 
in Section 9(j) of this Article Fourth, acquires beneficial ownership of 
shares representing 15% or more of the number of then outstanding shares of 
Common Stock and such Person or group (a "Significant Stockholder") does not 
then beneficially own an equal or greater percentage of all then outstanding 
shares of the Class A Common Stock, all of which Class A Common Stock must 
have been acquired by such Significant Stockholder after the Effective Time, 
such Significant Stockholder must, within a ninety (90) day period beginning 
the day after becoming a Significant Stockholder, make a public cash tender 
offer in compliance with all applicable laws and regulations to acquire 
additional shares of Class A Common Stock as provided in this Section 9 of 
Article Fourth (a "Class A Protection Transaction").  

         (b)  In each Class A Protection Transaction, the Significant 
Stockholder must make a public tender offer to acquire that number of 
additional shares of Class A Common Stock determined by (i) multiplying the 
percentage of the number of outstanding shares of Common Stock beneficially 
owned and acquired after the Effective Time by such Significant Stockholder 
by the total number of shares of Class A Common Stock outstanding on the date 
such Person or group became a Significant Stockholder, and (ii) subtracting 
therefrom the number of shares of Class A Common Stock beneficially owned by 
such Significant Stockholder on the date such Person or group became a 
Significant Stockholder which were acquired after the Effective Time (as 
adjusted for stock splits, stock dividends and similar recapitalizations). 
The Significant Stockholder must acquire all shares validly tendered; or if 
the number of shares of Class A Common Stock tendered to the Significant 
Stockholder exceeds the number of shares required to be acquired pursuant to 
this Section 9(b), the number of shares of Class A Common Stock acquired from 
each tendering holder shall be pro rata based on the percentage that the 
number of shares tendered by such stockholder bears to the total number of 
shares tendered by all tendering holders.

         (c)  The offer price for any Class A Common Stock required to be 
purchased by the Significant Stockholder pursuant to Section 9 of this 
Article Fourth shall be the greatest of (i) the highest 




price per share paid by the Significant Stockholder for any Common Stock or 
Class A Common Stock during the six month period ending on the date such 
Person or group became a Significant Stockholder (or such shorter period if 
the date such Person or group became a Significant Stockholder is not more 
than six months following the Effective Time), (ii) the highest reported sale 
price of Common Stock or Class A Common Stock on The NASDAQ Stock Market 
National Market System ("NASDAQ/NMS") (or such other securities exchange or 
quotation system as is then the principal trading market for such shares) 
during the 30 day period preceding such Person or group becoming a 
Significant Stockholder, and (iii) the highest reported sale price of Common 
Stock or Class A Common Stock on the NASDAQ/NMS (or such other securities 
exchange or quotation system as is then the principal trading market for such 
shares) on the business day preceding the date the Significant Stockholder 
makes the tender offer required by this Section 9 of this Article Fourth. For 
purposes of Section 9(d) of this Article Fourth, the applicable date for each 
calculation required by clauses (i) and (ii) of the preceding sentence shall 
be the date on which the Significant Stockholder becomes required to engage 
in the Class A Protection Transaction for which such calculation is required. 
In the event that the Significant Stockholder has acquired Common Stock or 
Class A Common Stock in the six month period ending on the date such Person 
or group becomes a Significant Stockholder for  consideration other than 
cash, the value of such consideration per share of Common Stock shall be as 
determined in good faith by the Board of Directors.

         (d)  A Class A Protection Transaction shall also be required to be 
effected by any Significant Stockholder each time that the Significant 
Stockholder acquires after the Effective Time beneficial ownership of 
additional Common Stock in an amount equal to or greater than the next higher 
multiple of 5% in excess of 15% (e.g., 20%, 25%, 30%, etc.) of the number of 
outstanding shares of Common Stock if such Significant Stockholder does not 
then own an equal or greater percentage of the Class A Common Stock (all of 
which Class A Common Stock must have been acquired by such  Significant 
Stockholder after the Effective Time).  Such Significant Stockholder shall be 
required to make a public cash tender offer to acquire that number of shares 
of Class A Common Stock prescribed by the formula set forth in Section 9(b) 
of this Article Fourth, and must acquire all shares  validly tendered or a 
pro rata portion hereof, as specified in such Section 9(b), at the price 
determined pursuant to Section 9(c) of this Article Fourth, even if a 
previous Class A Protection Transaction resulted in fewer shares of Class A 
Common Stock being tendered than the Significant Stockholder was required to 
offer to purchase in the previous offer.

         (e)  If any Significant Stockholder fails to make an offer required 
by this Section 9 of this Article Fourth, or to purchase shares validly 
tendered and not withdrawn (after proration, if any), such Significant 
Stockholder shall not be entitled to vote any Common Stock beneficially owned 
by such Significant Stockholder and acquired by such Significant Stockholder 
after the Effective Time unless and until such requirements are complied with 
or unless and until all shares of Common Stock causing such offer requirement 
to be effective are no longer beneficially owned by such Significant 
Stockholder.  To the extent that the voting power of any shares of Common 
Stock is so suspended, such shares shall not be included in the determination 
of aggregate voting shares for any purpose under this Amended Restated 
Certificate of Incorporation or the Delaware General Corporation Law. The  
requirement to engage in a Class A Protection Transaction is satisfied by the 
making of the requisite offer and purchasing validly tendered shares pursuant 
to this Section 9 of this Article Fourth, even if the number of shares 
tendered is less than the number of shares the Significant Shareholder was 
required to offer to purchase.

         (f)  The Class A Protection Transaction requirement shall not apply 
to any increase in percentage beneficial ownership of Common Stock resulting 
solely from a change in the aggregate amount of Common Stock outstanding, 
provided that any acquisition after such change which resulted in any Person 
or group beneficially owning fifteen percent (15%) or more of the number of 
outstanding shares of 



Common Stock (or an additional 5% or more of the number of shares of the 
Common Stock after the last acquisition which triggered the requirement for a 
Class A Protection Transaction) shall be subject to any Class A Protection 
Transaction requirement that would be imposed pursuant to this Section 9 of 
this Article Fourth.

         (g)  In connection with Sections 9(a) through 9(d) of this Article 
Fourth, the following shares of Common Stock shall be excluded for the 
purpose of determining the shares of Common Stock beneficially owned by such 
Person or group but not for the purpose of determining shares outstanding:

              (i)     shares beneficially owned by such Person or group at the
    Effective Time;

              (ii)    shares acquired by will or by the laws of descent and 
    distribution, or by gift that is made in good faith and not for the purpose
    of circumventing this Section 9 of Article Fourth or by foreclosure of a
    bona fide loan;

              (iii)   shares acquired upon issuance or sale by the Corporation,
    including shares issued by the Corporation in a merger or consolidation
    involving the Corporation or a subsidiary;

              (iv)    shares acquired by operation of law (including a merger
    or consolidation effected for the purpose of recapitalizing such Person or
    reincorporating such Person in another jurisdiction but excluding a merger
    or consolidation effected by such person for the purpose of acquiring
    another Person);

              (v)     shares acquired in exchange for Class A Common Stock by a
    holder of  Class A Common Stock (or by a parent, lineal descendant or donee
    of such holder of Class A Common Stock who received such Class A Common
    Stock from such holder) if the Class A Common Stock so exchanged were
    acquired by such holder directly from the Corporation as a result of a
    stock split effected by this Amended Restated Certificate of Incorporation
    at the Effective Time or any subsequent stock split or as a dividend on
    Common Stock; and 

              (vi)    shares acquired by a plan of the Corporation qualified
    under Section 401(a) of the Internal Revenue Code of 1986, as amended, or
    any successor provision thereto, or acquired by reason of a distribution
    from such a plan.

         (h)   In connection with Sections 9(a) through 9(b) of this Article
Fourth, for purposes of calculating the number of shares of Class A Common Stock
beneficially owned by any Persons or group:

              (i)     Class A Common Stock acquired by gift shall be deemed to
    be beneficially owned by such Person or member of a group if such gift was
    made in good faith and not for the purpose of  circumventing the operations
    of this Section 9 of this Article Fourth; and

              (ii)    only Class A Common Stock owned of record by such Person
    or member of a group or held by others as nominees of such Person or member
    of a group and identified as such to the Corporation shall be deemed to be
    beneficially owned by such Person or group (provided that Class A Common
    Stock with respect to which such Person or member of a group has sole
    investment and voting power shall be deemed to be beneficially owned
    thereby).



         (i)  All calculations with respect to percentage beneficial ownership
of  either issued and outstanding Common Stock or Class A Common Stock will be
based upon the numbers of issued and outstanding shares reflected in either the
records of or a certification from the Corporation's stock transfer agent or
reported by the Corporation on the last to be filed of (i) the Corporation's
most recent Annual Report on Form 10-K, (ii) its most recent Quarterly Report on
Form 10-Q, (iii) its most recent Current Report on Form 8-K, and (iv) its most
recent definitive proxy statement filed with the Securities and Exchange
Commission.

         (j)  For purposes of this Section 9 of this Article Fourth, the term
"Person" means any individual, partnership, corporation, association, trust, or
other entity (other than the Corporation). Subject to Sections 9(g) and 9(h) of
this Article Fourth, "beneficial ownership" shall be determined pursuant to 
Rule 13d-3 promulgated under the Securities Exchange Act of 1934, as amended 
(the "1934 Act"), or any successor regulation and the formation or existence 
of a "group" shall be determined pursuant to Rule 13d-5(b) under the 1934 Act 
or any successor regulation, subject to the following qualifications:

              (i)     relationships by blood or marriage between or among any
    Persons will not constitute any of such Persons as a member of a group with
    such other Person, absent affirmative attributes of concerted action; and 

              (ii)    any Person acting in his official capacity as a director
    or officer of the Corporation shall not be deemed to beneficially own
    shares where such ownership exists solely by virtue of such Person's status
    as a trustee (or similar position) with respect to shares held by plans or
    trusts for the general benefit of employees or former employees of the
    Corporation, and actions taken or agreed to be taken by a Person in such
    Person's official capacity as an officer or director of the Corporation
    will not cause such Person to become a member of a group with any other
    Person.

    10.  ADDITIONAL VOTING RIGHTS OF CLASS A COMMON STOCK.  Each share of 
Class A Common Stock (whether or not then issued) shall be entitled to vote 
on all matters presented to the stockholders of the Corporation (i) 
automatically at the time the number of outstanding shares of Common Stock is 
less than 10% of the aggregate umber of outstanding shares of Common Stock 
and Class A Common Stock; or (ii) upon resolution of the Board of Directors, 
if as a result of the existence of the Class A Common Stock, either the 
Common Stock or Class A Common Stock or both are, or will be, excluded from 
quotation on NASDAQ/NMS and other comparable quotation systems then in use 
and are also, or will be, excluded from trading on the New York Stock 
Exchange, the American Stock Exchange and all other principal national 
securities exchanges then in use.  The Board of Directors shall have the 
power to determine whether the conditions set forth in clauses (i) or (ii) 
above have occurred.  In making its determination, the Board of Directors may 
conclusively rely on information and documentation available to it, including 
but not limited to, information or certification from its stock transfer 
agent, filings made with the Securities and Exchange Commission, any stock 
exchange, the National Association of Securities Dealers, Inc., or any other 
national quotation system.  The determination of the Board of Directors that 
the conditions described in either (i) or (ii) have occurred shall be 
conclusive and binding and the acquisition of voting rights by each share of 
Class A Common Stock shall remain effective regardless of whether the 
conditions described in (i) or (ii) have occurred in fact."

    SECOND:   That thereafter, pursuant to the By-Laws of said Corporation 
and resolution of its Board of Directors, the next annual meeting of the 
stockholders of said Corporation was held on 



September 9, 1997, 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 the aforesaid amendment was duly adopted in accordance with 
the applicable provisions of Section 242 of the General Corporation Law of 
the State of Delaware.

    IN WITNESS WHEREOF, said Hach Company has caused this certificate to be 
signed by Bruce J. Hach, its President, and Robert O. Case, its Secretary, 
this 9th day of September, 1997.

                             HACH COMPANY


                             By: /s/ Bruce J. Hach
                                 ------------------------------------
                                     Bruce J. Hach, President


                             By: /s/ Robert O. Case
                                 ------------------------------------
                                     Robert O. Case, Secretary