BY-LAWS
                                          of
                                    HACH  COMPANY

                 Incorporated under the Laws of the State of Delaware

                                      ARTICLE I

                                 OFFICES AND RECORDS


    SECTION 1.1.   DELAWARE OFFICE.  The principal office of the Corporation in
the State of Delaware shall be located in the City of Wilmington, County of New
Castle, and the name and address of its registered agent is The Corporation
Trust Company, 1209 Orange Street, Wilmington, Delaware.

    SECTION 1.2.   OTHER OFFICES.  The Corporation may have such other offices,
either within or without the State of Delaware, as the Board of Directors may
designate or as the business of the Corporation may from time to time require.

    SECTION 1.3.   BOOKS AND RECORDS. The books and records of the Corporation
may be kept outside the State of Delaware at such place or places as may from
time to time be designated by the Board of Directors.

                                      ARTICLE II

                                     STOCKHOLDERS

    SECTION 2.1.   ANNUAL MEETING.  The annual meeting of the stockholders of
the Corporation shall be held at such time and at such place within or without
the State of Delaware as may be fixed by resolution of the Board of Directors.

    SECTION 2.2.   SPECIAL MEETING.  Subject to the rights of the holders of
any series of stock having a preference over the Common Stock of the Corporation
as to dividends or upon liquidation ("Preferred Stock") with respect to such
series of Preferred Stock, special meetings of the stockholders may be called
only by the Chairman of the Board or by the Board of Directors pursuant to a
resolution adopted by a majority of the total number of directors which the
Corporation would have if there were no vacancies (the "Whole Board").

    SECTION 2.3.   PLACE OF MEETING.  The Board of Directors or the Chairman of
the Board, as the case may be, may designate the place of meeting for any annual
meeting or for any special meeting of the stockholders called by the Board of
Directors or the Chairman of the Board. If no designation is so made, the place
of meeting shall be the principal office of the Corporation.


                                         -22-



    SECTION 2.4.   NOTICE OF MEETING.  Written or printed notice, stating the
place, day and hour of the meeting and the purpose or purposes for which the
meeting is called, shall be delivered by the Corporation not less than ten (10)
days nor more than sixty (60) days before the date of the meeting, either
personally or by mail, to each stockholder of record entitled to vote at such
meeting. If mailed, such notice shall be deemed to be delivered when deposited
in the United States mail with postage thereon prepaid, addressed to the
stockholder at his address as it appears on the stock transfer books of the
Corporation. Such further notice shall be given as may be required by law. Only
such business shall be conducted at a special meeting of stockholders as shall
have been brought before the meeting pursuant to the Corporation's notice of
meeting. Meetings may be held without notice if all stockholders entitled to
vote are present, or if notice is waived by those not present in accordance with
Section 6.4 of these By-Laws.  Any previously scheduled meeting of the
stockholders may be postponed, and (unless the certificate of Incorporation
otherwise provides) any special meeting of the stockholders may be canceled, by
resolution of the Board of Directors upon public notice given prior to the date
previously scheduled for such meeting of stockholders.

    SECTION 2.5.   QUORUM AND ADJOURNMENT.  Except as otherwise provided by law
or by the Certificate of Incorporation, the holders of a majority of the
outstanding shares of the Corporation entitled to vote generally in the election
of directors (the "Voting Stock"), represented in person or by proxy, shall
constitute a quorum at a meeting of stockholders, except that when specified
business is to be voted on by a class or series of stock voting as a class, the
holders of a majority of the shares of such class or series shall constitute a
quorum of such class or series for the transaction of such business.  The
Chairman of the meeting or a majority of the shares so represented may adjourn
the meeting from time to time, whether or not there is such a quorum. No notice
of the time and place of adjourned meetings need be given except as required by
law. The stockholders present at a duly called meeting at which a quorum is
present may continue to transact business until adjournment, notwithstanding the
withdrawal of enough stockholders to leave less than a quorum.

    SECTION 2.6.   PROXIES.  At all meetings of stockholders, a stockholder may
vote by proxy executed in writing (or in such manner prescribed by the General
Corporation Law of the State of Delaware) by the stockholder, or by his duly
authorized attorney in fact.

    SECTION 2.7.   NOTICE OF STOCKHOLDER BUSINESS AND NOMINATIONS.

         (A)  ANNUAL MEETINGS OF STOCKHOLDERS.  (1) Nominations of persons for
election to the Board of Directors of the Corporation and the proposal of
business to be considered by the stockholders may be made at an annual meeting
of stockholders (a) pursuant to the Corporation's notice of meeting, (b) by or
at the direction of the Board of Directors or (c) by any stockholder of the
Corporation who was a stockholder of record at the time of giving of notice
provided for in this By-Law, who is entitled to vote at the meeting and who
complies with the notice procedures set forth in this By-Law.


                                         -23-



              (2)  For nominations or other business to be properly brought
before an annual meeting by a stockholder pursuant to clause (c) of paragraph
(A)(1) of this By-Law, the stockholder must have given timely notice thereof in
writing to the Secretary of the Corporation and such other business must
otherwise be a proper matter for stockholder action. To be timely, a
stockholder's notice shall be delivered to the Secretary at the principal
executive offices of the Corporation not later than the close of business on the
60th day nor earlier than the close of business on the 90th day prior to the
first anniversary of the preceding year's annual meeting; provided, however,
that in the event that the date of the annual meeting is more than 30 days
before or more than 60 days after such anniversary date, notice by the
stockholder to be timely must be so delivered not earlier than the close of
business on the 90th day prior to such annual meeting and not later than the
close of business on the later of the 60th day prior to such annual meeting or
the 10th day following the day on which public announcement of the date of such
meeting is first made by the Corporation. In no event shall the public
announcement of an adjournment of an annual meeting commence a new time period
for the giving of a stockholder's notice as described above. Such stockholder's
notice shall set forth (a) as to each person whom the stockholder proposes to
nominate for election or re-election as a director all information relating to
such person that is required to be disclosed in solicitations of proxies for
election of directors in an election contest, or is otherwise required, in each
case pursuant to Regulation 14A under the Securities Exchange Act of 1934, as
amended (the "Exchange Act") and Rule 14a-l l thereunder (including such
person's written consent to being named in the proxy statement as a nominee and
to serving as a director if elected); (b) as to any other business that the
stockholder proposes to bring before the meeting, a brief description of the
business desired to be brought before the meeting, the reasons for conducting
such business at the meeting and any material interest in such business of such
stockholder and the beneficial owner, if any, on whose behalf the proposal is
made; and (c) as to the stockholder giving the notice and the beneficial owner,
if any, on whose behalf the nomination or proposal is made (i) the name and
address of such stockholder, as they appear on the Corporation's books, and of
such beneficial owner and (ii) the class and number of shares of the Corporation
which are owned beneficially and of record by such stockholder and such
beneficial owner.

              (3)  Notwithstanding anything in the second sentence of paragraph
(A)(2) of this By-Law to the contrary, in the event that the number of directors
to be elected to the Board of Directors of the Corporation is increased and
there is no public announcement by the Corporation naming all of the nominees
for director or specifying the size of the increased Board of Directors at least
70 days prior to the first anniversary of the preceding year's annual meeting, a
stockholder's notice required by this By-Law shall also be considered timely,
but only with respect to nominees for any new positions created by such
increase, if it shall be delivered to the Secretary at the principal executive
offices of the Corporation not later than the close of business on the 10th day
following the day on which such public announcement is first made by the
Corporation.


                                         -24-



         (B)  SPECIAL MEETINGS OF STOCKHOLDERS.  Only such business shall be
conducted at a special meeting of stockholders as shall have been brought before
the meeting pursuant to the Corporation's notice of meeting. Nominations of
persons for election to the Board of Directors may be made at a special meeting
of stockholders at which directors are to be elected pursuant to the
Corporation's notice of meeting (a) by or at the direction of the Board of
Directors or (b) provided that the Board of Directors has determined that
directors shall be elected at such meeting, by any stockholder of the
Corporation who is a stockholder of record at the time of giving of notice
provided for in this By-Law, who shall be entitled to vote at the meeting and
who complies with the notice procedures set forth in this By-Law. In the event
the Corporation calls a special meeting of stockholders for the purpose of
electing one or more directors to the Board of Directors, any such stockholder
may nominate a person or persons (as the case may be), for election to such
position(s) as specified in the Corporation's notice of meeting, if the
stockholder's notice required by paragraph (A)(2) of this By-Law shall be
delivered to the Secretary at the principal executive offices of the Corporation
not earlier than the close of business on the 90th day prior to such special
meeting and not later than the close of business on the later of the 60th day
prior to such special meeting or the 10th day following the day on which public
announcement is first made of the date of the special meeting and of the
nominees proposed by the Board of Directors to be elected at such meeting. In no
event shall the public announcement of an adjournment of a special meeting
commence a new time period for the giving of a stockholder's notice as described
above.

         (C)  GENERAL.  (1) Only such persons who are nominated in accordance
with the procedures set forth in this By-Law shall be eligible to serve as
directors and only such business shall be conducted at a meeting of stockholders
as shall have been brought before the meeting in accordance with the procedures
set forth in this By-Law. Except as otherwise provided by law, the Certificate
of Incorporation or these By-Laws, the Chairman of the meeting shall have the
power and duty to determine whether a nomination or any business proposed to be
brought before the meeting was made or proposed, as the case may be, in
accordance with the procedures set forth in this By-Law and, if any proposed
nomination or business is not in compliance with this By-Law, to declare that
such defective proposal or nomination shall be disregarded.

              (2)  For purposes of this By-Law, "public announcement" shall
mean disclosure in a press release reported by the Dow Jones News Service,
Associated Press or comparable national news service or in a document publicly
filed by the Corporation with the Securities and Exchange Commission pursuant to
Section 13, 14 or 15(d) of the Exchange Act.

              (3)  Notwithstanding the foregoing provisions of this By-Law, a
stockholder shall also comply with all applicable requirements of the Exchange
Act and the rules and regulations thereunder with respect to the matters set
forth in this By-Law. Nothing in this By-Law shall be deemed to affect any
rights (i) of stockholders to request inclusion of proposals in the
Corporation's proxy statement pursuant to Rule 14a-8 under the Exchange Act or
(ii) of the holders of any series of Preferred Stock to elect directors under
specified circumstances.


                                         -25-



    SECTION 2.8.   PROCEDURE FOR ELECTION OF DIRECTORS; REQUIRED VOTE.
Election of directors at all meetings of the stockholders at which directors are
to be elected shall be by ballot, and, subject to the rights of the holders of
any series of Preferred Stock to elect directors under specified circumstances,
a plurality of the votes cast thereat shall elect directors. Except as otherwise
provided by law, the Certificate of Incorporation, or these By-Laws, in all
matters other than the election of directors, the affirmative vote of a majority
of the shares present in person or represented by proxy at the meeting and
entitled to vote on the matter shall be the act of the stockholders.

    SECTION 2.9.   INSPECTORS OF ELECTIONS; OPENING AND CLOSING THE POLLS.  The
Board of Directors by resolution shall appoint one or more inspectors, which
inspector or inspectors may include individuals who serve the Corporation in
other capacities, including, without limitation, as officers, employees, agents
or representatives, to act at the meetings of stockholders and make a written
report thereof. One or more persons may be designated as alternate inspectors to
replace any inspector who fails to act. If no inspector or alternate has been
appointed to act or is able to act at a meeting of stockholders, the Chairman of
the meeting shall appoint one or more inspectors to act at the meeting. Each
inspector, before discharging his or her duties, shall take and sign an oath
faithfully to execute the duties of inspector with strict impartiality and
according to the best of his or her ability. The inspectors shall have the
duties prescribed by law.

         The Chairman of the meeting shall fix and announce at the meeting the
date and time of the opening and the closing of the polls for each matter upon
which the stockholders will vote at a meeting.

    SECTION 2.10.  RECORD DATE FOR ACTION BY WRITTEN CONSENT.  In order that
the Corporation may determine the stockholders entitled to consent to corporate
action in writing without a meeting, the Board of Directors may fix a record
date, which record date shall not precede the date upon which the resolution
fixing the record date is adopted by the Board of Directors, and which date
shall not be more than 10 days after the date upon which the resolution fixing
the record date is adopted by the Board of Directors. Any stockholder of record
seeking to have the stockholders authorize or take corporate action by written
consent shall, by written notice to the Secretary, request the Board of
Directors to fix a record date. The Board of Directors shall promptly, but in
all events within 10 days after the date on which such a request is received,
adopt a resolution fixing the record date. If no record date has been fixed by
the Board of Directors within 10 days of the date on which such a request is
received, the record date for determining stockholders entitled to consent to
corporate action in writing without a meeting, when no prior action by the Board
of Directors is required by applicable law, shall be the first date
on which a signed written consent setting forth the action taken or proposed to
be taken is delivered to the Corporation by delivery to its registered office in
Delaware, its principal place of business or to any officer or agent of the
Corporation having custody of the book in which proceedings of meetings of
stockholders are recorded. Delivery made to the Corporation's registered office
shall be by hand or by certified or registered mail, return receipt requested.
If no


                                         -26-



record date has been fixed by the Board of Directors and prior action by the
Board of Directors is required by applicable law, the record date for
determining stockholders entitled to consent to corporate action in writing
without a meeting shall be at the close of business on the date on which the
Board of Directors adopts the resolution taking such prior action.

    SECTION 2.11.  INSPECTORS OF WRITTEN CONSENT.  In the event of the
delivery, in the manner provided by Section 2.10, to the Corporation of the
requisite written consent or consents to take corporate action and/or any
related revocation or revocations, the Corporation shall engage nationally
recognized independent inspectors of elections for the purpose of promptly
performing a ministerial review of the validity of the consents and revocations.
For the purpose of permitting the inspectors to perform such review, no action
by written consent without a meeting shall be effective until such date as the
independent inspectors certify to the Corporation that the consents delivered to
the Corporation in accordance with Section 2.10 represent at least the minimum
number of votes that would be necessary to take the corporate action. Nothing
contained in this paragraph shall in any way be construed to suggest or imply
that the Board of Directors or any stockholder shall not be entitled to contest
the validity of any consent or revocation thereof, whether before or after such
certification by the independent inspectors, or to take any other action
(including, without limitation, the commencement, prosecution or defense of any
litigation with respect thereto, and the seeking of injunctive relief in such
litigation).

    SECTION 2.12.  EFFECTIVENESS OF WRITTEN CONSENT.  Every written consent
shall bear the date of signature of each stockholder who signs the consent and
no written consent shall be effective to take the corporate action referred to
therein unless, within 60 days of the date the earliest dated written consent
was received in accordance with Section 2.10, a written consent or consents
signed by a sufficient number of holders to take such action are delivered to
the Corporation in the manner prescribed in Section 2.10.

                                     ARTICLE III

                                  BOARD OF DIRECTORS

    SECTION 3.1.   GENERAL POWERS.  The business and affairs of the Corporation
shall be managed under the direction of the Board of Directors. In addition to
the powers and authorities by these By-Laws expressly conferred upon them, the
Board of Directors may exercise all such powers of the Corporation and do all
such lawful acts and things as are not by statute or by the Certificate of
Incorporation or by these By-Laws required to be exercised or done by the
stockholders.

    SECTION 3.2.   NUMBER, TENURE AND QUALIFICATIONS.  Subject to the rights of
the holders of any series of Preferred Stock to elect directors under specified
circumstances, the number of directors shall be fixed from time to time
exclusively pursuant to a resolution adopted by a majority of the Whole Board
but in no case shall the number of directors be less than three. Each director
shall be elected for a term of one year and until his successor is elected and
qualified, except as otherwise provided herein or required by law.


                                         -27-



    SECTION 3.3.   REGULAR MEETINGS.  A regular meeting of the Board of
Directors shall be held without other notice than this By-Law immediately after,
and at the same place as, the Annual Meeting of Stockholders. The Board of
Directors may, by resolution, provide the time and place for the holding of
additional regular meetings without other notice than such resolution.

    SECTION 3.4.   SPECIAL MEETINGS.  Special meetings of the Board of
Directors shall be called at the request of the Chairman of the Board, the
President or a majority of the Board of Directors then in office. The person or
persons authorized to call special meetings of the Board of Directors may fix
the place and time of the meetings.

    SECTION 3.5.   NOTICE.  Notice of any special meeting of directors shall be
given to each director at his business or residence in writing by hand delivery,
first-class or overnight mail or courier service, telegram or facsimile
transmission, or orally by telephone. If mailed by First-class mail, such notice
shall be deemed adequately delivered when deposited in the United States mails
so addressed, with postage thereon prepaid, at least five (5) days before such
meeting. If by telegram, overnight mail or courier service, such notice shall be
deemed adequately delivered when the telegram is delivered to the telegraph
company or the notice is delivered to the overnight mail or courier service
company at least twenty-four (24) hours before such meeting. If by facsimile
transmission, such notice shall be deemed adequately delivered when the notice
is transmitted at least twelve (12) hours before such meeting. If by telephone
or by hand delivery, the notice shall be given at least twelve (12) hours prior
to the time set for the meeting. Neither the business to be transacted at, nor
the purpose of, any regular or special meeting of the Board of Directors need be
specified in the notice of such meeting, except for amendments to these By-Laws,
as provided under Section 8.1. A meeting may be held at any time without notice
if all the directors are present or if those not present waive notice of the
meeting in accordance with Section 6.4 of these By-Laws.

    SECTION 3.6.   ACTION BY CONSENT OF BOARD OF DIRECTORS.  Any action
required or permitted to be taken at any meeting of the Board of Directors or of
any committee thereof may be taken without a meeting if all members of the Board
or committee, as the case may be, consent thereto in writing, and the writing or
writings are filed with the minutes of proceedings of the Board or committee.

    SECTION 3.7.   CONFERENCE TELEPHONE MEETINGS.  Members of the Board of
Directors, or any committee thereof, may participate in a meeting of the Board
of Directors or such committee by means of conference telephone or similar
communications equipment by means of which all persons participating in the
meeting can hear each other, and such participation in a meeting shall
constitute presence in person at such meeting.


                                         -28-


    SECTION 3.8.   QUORUM.  Subject to Section 3.9, a whole number of directors
equal to at least a majority of the Whole Board shall constitute a quorum for
the transaction of business, but if at any meeting of the Board of Directors
there shall be less than a quorum present, a majority of the directors present
may adjourn the meeting from time to time without further notice. The act of the
majority of the directors present at a meeting at which a quorum is present
shall be the act of the Board of Directors. The directors present at a duly
organized meeting may continue to transact business until adjournment,
notwithstanding the withdrawal of enough directors to leave less than a quorum.

    SECTION 3.9.   VACANCIES.  Subject to applicable law and the rights of the
holders of any series of Preferred Stock with respect to such series of
Preferred Stock, and unless the Board of Directors otherwise determines,
vacancies resulting from death, resignation, retirement, disqualification,
removal from office or other cause, and newly created directorships resulting
from any increase in the authorized number of directors, may be filled only by
the affirmative vote of a majority of the remaining directors, though less than
a quorum of the Board of Directors, and directors so chosen shall hold office
for a term expiring at the next annual meeting of stockholders and until such
director's successor shall have been duly elected and qualified. No decrease in
the number of authorized directors constituting the Whole Board shall shorten
the term of any incumbent director.

    SECTION 3.10.  EXECUTIVE AND OTHER COMMITTEES.  The Board of Directors may,
by resolution adopted by a majority of the Whole Board, designate an Executive
Committee to exercise, subject to applicable provisions of law, all the powers
of the Board in the management of the business and affairs of the Corporation
when the Board is not in session, including without limitation the power to
declare dividends, to authorize the issuance of the Corporation's capital stock
and to adopt a certificate of ownership and merger pursuant to Section 253 of
the General Corporation Law of the State of Delaware, and may, by resolution
similarly adopted, designate one or more other committees. The Executive
Committee and each such other committee shall consist of two or more directors
of the Corporation. The Board may designate one or more directors as alternate
members of any committee, who may replace any absent or disqualified member at
any meeting of the committee. Any such committee, other than the Executive
Committee (the powers of which are expressly provided for herein), may to the
extent permitted by law exercise such powers and shall have such
responsibilities as shall be specified in the designating resolution. In the
absence or disqualification of any member of such committee or committees, the
member or members thereof present at any meeting and not disqualified from
voting, whether or not constituting a quorum, may unanimously appoint another
member of the Board to act at the meeting in the place of any such absent or
disqualified member. Each committee shall keep written minutes of its
proceedings and shall report such proceedings to the Board when required.


                                         -29-



         A majority of any committee may determine its action and fix the time
and place of its meetings, unless the Board shall otherwise provide. Notice of
such meetings shall be given to each member of the committee in the manner
provided for in Section 3.5 of these By-Laws. The Board shall have power at any
time to fill vacancies in, to change the membership of, or to dissolve any such
committee. Nothing herein shall be deemed to prevent the Board from appointing
one or more committees consisting in whole or in part of persons who are not
directors of the Corporation; PROVIDED, HOWEVER, that no such committee shall
have or may exercise any authority of the Board.

    SECTION 3.11.  REMOVAL. Subject to the rights of the holders of any series
of Preferred Stock with respect to such series of Preferred Stock, any director,
or the entire Board of Directors, may be removed from office either for or
without cause by the affirmative vote of the holders of a majority of all the
shares of stock outstanding and entitled to vote.

    SECTION 3.12.  RECORDS.  The Board of Directors shall cause to be kept a
record containing the minutes of the proceedings of the meetings of the Board
and of the stockholders, appropriate stock books and registers and such books of
records and accounts as may be necessary for the proper conduct of the business
of the Corporation.

                                      ARTICLE IV

                                       OFFICERS


    SECTION 4.1.   ELECTED OFFICERS.  The elected officers of the Corporation
shall be a Chairman of the Board of Directors, a President, a Secretary, a
Treasurer, and such other officers (including, without limitation, a Chief
Financial Officer) as the Board of Directors from time to time may deem proper.
The Chairman of the Board shall be chosen from among the directors. All officers
elected by the Board of Directors shall each have such powers and duties as
generally pertain to their respective offices, subject to the specific
provisions of this ARTICLE IV. Such officers shall also have such powers and
duties as from time to time may be conferred by the Board of Directors or by any
committee thereof. The Board or any committee thereof may from time to time
elect, or the Chairman of the Board or President may appoint, such other
officers (including one or more Assistant Vice Presidents, Assistant
Secretaries, Assistant Treasurers, and Assistant Controllers) and such agents,
as may be necessary or desirable for the conduct of the business of the
Corporation. Such other officers and agents shall have such duties and shall
hold their offices for such terms as shall be provided in these By-Laws or as
may be prescribed by the Board or such committee or by the Chairman of the Board
or President, as the case may be.


                                         -30-



    SECTION 4.2.   ELECTION AND TERM OF OFFICE.  The elected officers of the
Corporation shall be elected annually by the Board of Directors at the regular
meeting of the Board of Directors held after the annual meeting of the
stockholders. If the election of officers shall not be held at such meeting,
such election shall be held as soon thereafter as convenient. Each officer shall
hold office until his successor shall have been duly elected and shall have
qualified or until his death or until he shall resign, but any officer my be
removed from office at any time by the affirmative vote of a majority of the
Whole Board or, except in the case of an officer or agent elected by the Board,
by the Chairman of the Board or President. Such removal shall be without
prejudice to the contractual rights, if any, of the person so removed.

    SECTION 4.3.   CHAIRMAN OF THE BOARD.  The Chairman of the Board shall
preside at all meetings of the stockholders and of the Board of Directors and
shall be the Chief Executive Officer of the Company. The Chairman of the Board
shall be responsible for the general management of the affairs of the
Corporation and shall perform all duties incidental to his office which may be
required by law and all such other duties as are properly required of him by the
Board of Directors. He shall make reports to the Board of Directors and the
stockholders, and shall see that all orders and resolutions of the Board of
Directors and of any committee thereof are carried into effect. The Chairman of
the Board may also serve as President, if so elected by the Board.

    SECTION 4.4.   PRESIDENT.  The President shall act in a general executive
capacity and shall assist the Chairman of the Board in the administration and
operation of the Corporation's business and general supervision of its policies
and affairs. The President shall, in the absence of or because of the inability
to act of the Chairman of the Board, perform all duties of the Chairman of the
Board and preside at all meetings of stockholders and of the Board of Directors.

    SECTION 4.5.   VICE-PRESIDENTS.  Each Vice President shall have such powers
and shall perform such duties as shall be assigned to him, by the Board of
Directors.

    SECTION 4.6.   CHIEF FINANCIAL OFFICER.  The Chief Financial Officer (if
any) shall be a Vice President and act in an executive financial capacity. He
shall assist the Chairman of the Board and the President in the general
supervision of the Corporation's financial policies and affairs.

    SECTION 4.7.   TREASURER.  The Treasurer shall exercise general supervision
over the receipt, custody and disbursement of corporate funds.  The Treasurer
shall cause the funds of the Corporation to be deposited in such banks as may be
authorized by the Board of Directors, or in such banks as may be designated as
depositories in the manner provided by resolution of the Board of Directors. He
shall have such further powers and duties and shall be subject to such
directions as may be granted or imposed upon him from time to time by the Board
of Directors, the Chairman of the Board or the President.


                                         -31-



    SECTION 4.8.   SECRETARY.  The Secretary shall keep or cause to be kept in
one or more books provided for that purpose, the minutes of all meetings of the
Board, the committees of the Board and the stockholders; he shall see that all
notices are duly given in accordance with the provisions of these By-Laws and as
required by law; he shall be custodian of the records and the seal of the
Corporation and affix and attest the seal to all stock certificates of the
Corporation (unless the seal of the Corporation on such certificates shall be a
facsimile, as hereinafter provided) and affix and attest the seal to all other
documents to be executed on behalf of the Corporation under its seal; and he
shall see that the books, reports, statements, certificates and other documents
and records required by law to be kept and filed are properly kept and filed;
and in general, he shall perform all the duties incident to the office of
Secretary and such other duties as from time to time may be assigned to him by
the Board, the Chairman of the Board or the President.

    SECTION 4.9.   REMOVAL.  Any officer elected, or agent appointed, by the
Board of Directors may be removed by the affirmative vote of a majority of the
Whole Board whenever, in their judgment, the best interests of the Corporation
would be served thereby. Any officer or agent appointed by the Chairman of the
Board or the President may be removed by him whenever, in his judgment, the best
interests of the Corporation would be served thereby. No elected officer shall
have any contractual rights against the Corporation for compensation by virtue
of such election beyond the date of the election of his successor, his death,
his resignation or his removal, whichever event shall first occur, except as
otherwise provided in an employment contract or under an employee deferred
compensation plan.

    SECTION 4.10.  VACANCIES.  A newly created elected office and a vacancy in
any elected office because of death, resignation, or removal may be filled by
the Board of Directors for the unexpired portion of the term at any meeting of
the Board of Directors. Any vacancy in an office appointed by the Chairman of
the Board or the President because of death, resignation, or removal may be
filled by the Chairman of the Board or the President.

                                      ARTICLE V

                           STOCK CERTIFICATES AND TRANSFERS

    SECTION 5.1.   STOCK CERTIFICATES AND TRANSFERS.  The interest of each
stockholder of the Corporation shall be evidenced by certificates for shares of
stock in such form as the appropriate officers of the Corporation may from time
to time prescribe. The shares of the stock of the Corporation shall be
transferred on the books of the Corporation by the holder thereof in person or
by his attorney, upon surrender for cancellation of certificates for at least
the same number of shares, with an assignment and power of transfer endorsed
thereon or attached thereto, duly executed, with such proof of the authenticity
of the signature as the Corporation or its agents may reasonably require.


                                         -32-



         The certificates of stock shall be signed, countersigned and
registered in such manner as the Board of Directors may by resolution prescribe,
which resolution may permit all or any of the signatures on such certificates to
be in facsimile. In case any officer, transfer agent or registrar who has signed
or whose facsimile signature has been placed upon a certificate has ceased to be
such officer, transfer agent or registrar before such certificate is issued, it
may be issued by the Corporation with the same effect as if he were such
officer, transfer agent or registrar at the date of issue.

    SECTION 5.2.   LOST, STOLEN OR DESTROYED CERTIFICATES. No certificate for
shares of stock in the Corporation shall be issued in place of any certificate
alleged to have been lost, destroyed or stolen, except on production of such
evidence of such loss, destruction or theft and on delivery to the Corporation
of a bond of indemnity in such mount, upon such terms and secured by such
surety, as the Board of Directors or any financial officer may in its or his
discretion require.

                                      ARTICLE VI

                               MISCELLANEOUS PROVISIONS

    SECTION 6.1.   FISCAL YEAR.  The fiscal year of the Corporation shall begin
on the first day of May and end on the thirtieth day of  April of each year.

    SECTION 6.2.   DIVIDENDS.  The Board of Directors may from time to time
declare, and the Corporation may pay, dividends on its outstanding shares in the
manner and upon the terms and conditions provided by law and the Certificate of
Incorporation.

    SECTION 6.3.   SEAL.  The corporate seal shall have inscribed thereon the
words "Corporate Seal", the year of incorporation and around the margin thereof
the words "Hach Company - Delaware."

    SECTION 6.4.   WAIVER OF NOTICE.  Whenever any notice is required to be
given to any stockholder or director of the Corporation under the provisions of
the General Corporation Law of the State of Delaware or these By-Laws, a waiver
thereof in writing, signed by the person or persons entitled to such notice,
whether before or after the time stated therein, shall be deemed equivalent to
the giving of such notice. Neither the business to be transacted at, nor the
purpose of, any annual or special meeting of the stockholders or the Board of
Directors or committee thereof need be specified in any waiver of notice of such
meeting.

    SECTION 6.5.   AUDITS.  The accounts, books and records of the Corporation
shall be audited upon the conclusion of each fiscal year by an independent
certified public accountant selected by the Board of Directors, and it shall be
the duty of the Board of Directors to cause such audit to be done annually.


                                         -33-



    SECTION 6.6.   RESIGNATIONS.  Any director or any officer, whether elected
or appointed, may resign at any time by giving written notice of such
resignation to the Chairman of the Board, the President, or the Secretary, and
such resignation shall be deemed to be effective as of the close of business on
the date said notice is received by the Chairman of the Board, the President, or
the Secretary, or at such later time as is specified therein. No formal action
shall be required of the Board of  Directors or the stockholders to make any
such resignation effective.

    SECTION 6.7.   INDEMNIFICATION AND INSURANCE.  (A) Each person who was or
is made a party or is threatened to be made a party to or is involved in any
action, suit, or proceeding, whether civil, criminal, administrative or
investigative (hereinafter a "proceeding"), by reason of the fact that he or she
or a person of whom he or she is the legal representative is or was a director
or officer of the Corporation or is or was serving at the request of the
Corporation as a director, officer, employee or agent of another corporation or
of a partnership, joint venture, trust or other enterprise, including service
with respect to employee benefit plans maintained or sponsored by the
Corporation, whether the basis of such proceeding is alleged action in an
official capacity as a director, officer, employee or agent or in any other
capacity while serving as a director, officer, employee or agent, shall be
indemnified and held harmless by the Corporation to the fullest extent
authorized by the General Corporation Law of the State of Delaware as the same
exists or may hereafter be amended (but, in the case of any such amendment, only
to the extent that such amendment permits the Corporation to provide broader
indemnification rights than said law permitted the Corporation to provide prior
to such amendment), against all expense, liability and loss (including
attorneys' fees, judgments, fees, ERISA excise taxes or penalties and amounts
paid or to be paid in settlement) reasonably incurred or suffered by such person
in connection therewith and such indemnification shall continue as to a person
who has ceased to be a director, officer, employee or agent and shall inure to
the benefit of his or her heirs, executors and administrators; provided,
however, that except as provided in paragraph (C) of this By-Law, the
Corporation shall indemnify any such person seeking indemnification in
connection with a proceeding (or part thereof) initiated by such person only if
such proceeding (or part thereof) was authorized by the Board of Directors. The
right to indemnification conferred in this By-Law shall be a contract right and
shall include the right to be paid by the Corporation the expenses incurred in
defending any such proceeding in advance of its final disposition, such advances
to be paid by the Corporation within 20 days after the receipt by the
Corporation of a statement or statements from the claimant requesting such
advance or advances from time to time; provided, however, that if the General
Corporation Law of the State of Delaware requires, the payment of such expenses
incurred by a director or officer in his or her capacity as a director or
officer (and not in any other capacity in which service was or is rendered by
such person while a director or officer, including, without limitation, service
to an employee benefit plan) in advance of the final disposition of a
proceeding, shall be made only upon delivery to the Corporation of an
undertaking by or on behalf of such director or officer, to repay all amounts so
advanced if it shall ultimately be determined that such director or officer is
not entitled to be indemnified under this By-Law or otherwise.


                                         -34-



         (B)  To obtain indemnification under this By-Law, a claimant shall
submit to the Corporation a written request, including therein or therewith such
documentation and information as is reasonably available to the claimant and is
reasonably necessary to determine whether and to what extent the claimant is
entitled to indemnification. Upon written request by a claimant for
indemnification pursuant to the first sentence of this paragraph (B), a
determination, if required by applicable law, with respect to the claimant's
entitlement thereto shall be made as follows: (1) if requested by the claimant,
by Independent Counsel (as hereinafter defined), or (2) if no request is made by
the claimant for a determination by Independent Counsel, (i) by the Board of
Directors by a majority vote of a quorum consisting of Disinterested Directors
(as hereinafter defined), or (ii) if a quorum of the Board of Directors
consisting of Disinterested Directors is not obtainable or, even if obtainable,
such quorum of Disinterested Directors so directs, by Independent Counsel in a
written opinion to the Board of Directors, a copy of which shall be delivered to
the claimant, or (iii) if a quorum of Disinterested Directors so directs, by the
stockholders of the Corporation. In the event the determination of entitlement
to indemnification is to be made by Independent Counsel at the request of the
claimant, the Independent Counsel shall be selected by the Board of Directors
unless there shall have occurred within two years prior to the date of the
commencement of the action, suit or proceeding for which indemnification is
claimed a "Change of Control" as defined in the 1995 Non-Employee Director Stock
Plan in which case the Independent Counsel shall be selected by the claimant
unless the claimant shall request that such selection be made by the Board of
Directors. If it is so determined that the claimant is entitled to
indemnification, payment to the claimant shall be made within 10 days after such
determination.

         (C)  If a claim under paragraph (A) of this By-Law is not paid in full
by the Corporation within 30 days after a written claim pursuant to paragraph
(B) of this By-Law has been received by the Corporation, the claimant may at any
time thereafter bring suit against the Corporation to recover the unpaid amount
of the claim and, if successful in whole or in part, the claimant shall be
entitled to be paid also the expense of prosecuting such claim. It shall be a
defense to any such action (other than an action brought to enforce a claim for
expenses incurred in defending any proceeding in advance of its final
disposition where the required undertaking, if any is required, has been
tendered to the Corporation) that the claimant has not met the standard of
conduct which makes it permissible under the General Corporation Law of the
State of Delaware for the Corporation to indemnify the claimant for the amount
claimed, but the burden of proving such defense shall be on the Corporation.
Neither the failure of the Corporation (including its Board of Directors,
Independent Counsel or stockholders) to have made a determination prior to the
commencement of such action that indemnification of the claimant is proper in
the circumstances because he or she has met the applicable standard of conduct
set forth in the General Corporation Law of the State of Delaware, nor an actual
determination by the Corporation (including its Board of Directors, Independent
Counsel or stockholders) that the claimant has not met such applicable standard
of conduct, shall be a defense to the action or create a presumption that the
claimant has not met the applicable standard of conduct.

         (D)  If a determination shall have been made pursuant to paragraph (B)
of this By-Law that the claimant is entitled to indemnification, the Corporation
shall be bound by such determination in any judicial proceeding commenced
pursuant to paragraph (C) of this By-Law.


                                         -35-



         (E)  The Corporation shall be precluded from asserting in any judicial
proceeding commenced pursuant to paragraph (C) of this By-Law that the
procedures and presumptions of this By-Law are not valid, binding and
enforceable and shall stipulate in such proceeding that the Corporation is bound
by all the provisions of this By-Law.

         (F)  The right to indemnification and the payment of expenses incurred
in defending a proceeding in advance of its final disposition conferred in this
By-Law shall not be exclusive of any other right which any person may have or
hereafter acquire under any statute, provision of the Certificate of
Incorporation, By-Laws, agreement, vote of stockholders or Disinterested
Directors or otherwise. No repeal or modification of this By-Law shall in any
way diminish or adversely affect the rights of any director, officer, employee
or agent of the Corporation hereunder in respect of any occurrence or matter
arising prior to any such repeal or modification.

         (G)  The Corporation may maintain insurance, at its expense, to
protect itself and any director, officer, employee or agent of the Corporation
or another corporation, partnership, joint venture, trust or other enterprise
against any expense, liability or loss, whether or not the Corporation would
have the power to indemnify such person against such expense, liability or loss
under the General Corporation Law of the State of Delaware. To the extent that
the Corporation maintains any policy or policies providing such insurance, each
such director or officer, and each such agent or employee to which rights to
indemnification have been granted as provided in paragraph (H) of this By-Law,
shall be covered by such policy or policies in accordance with its or their
terms to the maximum extent of the coverage thereunder for any such director,
officer, employee or agent.

         (H)  The Corporation may, to the extent authorized from time to time
by the Board of Directors, grant rights to indemnification, and rights to be
paid by the Corporation the expenses incurred in defending any proceeding in
advance of its final disposition, to any employee or agent of the Corporation to
the fullest extent of the provisions of this By-Law with respect to the
indemnification and advancement of expenses of directors and officers of the
Corporation.

         (I)  If any provision or provisions of this By-Law shall be held to be
invalid, illegal or unenforceable for any reason whatsoever: (1) the validity,
legality and enforceability of the remaining provisions of this By-Law
(including, without limitation, each portion of any paragraph of this By-Law
containing any such provision held to be invalid, illegal or unenforceable, that
is not itself held to be invalid, illegal or unenforceable) shall not in any way
be affected or impaired thereby; and (2) to the fullest extent possible, the
provisions of this By-Law (including, without limitation, each such portion of
any paragraph of this By-Law containing any such provision held to be invalid,
illegal or unenforceable) shall be construed so as to give effect to the intent
manifested by the provision held invalid, illegal or unenforceable.


                                         -36-



         (J)  For purposes of this By-Law:

              (1)  "Disinterested Director" means a director of the
              Corporation who is not and was not a party to the
              matter in respect of which indemnification is sought by
              the claimant.

              (2)  "Independent Counsel" means a law firm, a member
              of a law firm, or an independent practitioner, that is
              experienced in matters of corporation law and shall
              include any person who, under the applicable standards
              of professional conduct then prevailing, would not have
              a conflict of interest in representing either the
              Corporation or the claimant in an action to determine
              the claimant's rights under this By-Law.

         (K)  Any notice, request or other communication required or permitted
to be given to the Corporation under this By-Law shall be in writing and either
delivered in person or sent by telecopy, telex, telegram, overnight mail or
courier service, or certified or registered mail, postage prepaid, return
receipt requested, to the Secretary of the Corporation and shall be effective
only upon receipt by the Secretary.

                                     ARTICLE VII

                               CONTRACTS, PROXIES, ETC.

    SECTION 7.1.   CONTRACTS.  Except as otherwise required by law, the
Certificate of Incorporation or these By-Laws, any contracts or other
instruments may be executed and delivered in the name and on the behalf of the
Corporation by such officer or officers of the Corporation as the Board of
Directors may from time to time direct. Such authority may be general or
confined to specific instances as the Board may determine. The Chairman of the
Board, the President or any Vice President may execute bonds, contracts, deeds,
leases and other instruments to be made or executed for or on behalf of the
Corporation. Subject to any restrictions imposed by the Board of Directors or
the Chairman of the Board, the President or any Vice President of the
Corporation may delegate contractual powers to others under his jurisdiction, it
being understood, however, that any such delegation of power shall not relieve
such officer of responsibility with respect to the exercise of such delegated
power.



                                         -37-



    SECTION 7.2.   PROXIES.  Unless otherwise provided by resolution adopted by
the Board of Directors, the Chairman of the Board, the President or any Vice
President may from time to time appoint an attorney or attorneys or agent or
agents of the Corporation, in the name and on behalf of the Corporation, to cast
the votes which the Corporation may be entitled to cast as the holder of stock
or other securities in any other corporation, any of whose stock or other
securities may be held by the Corporation, at meetings of the holders of the
stock or other securities of such other corporation, or to consent in writing,
in the name of the Corporation as such holder, to any action by such other
corporation, and may instruct the person or persons so appointed as to the
manner of casting such votes or giving such consent, and may execute or cause to
be executed in the name and on behalf of the Corporation and under its corporate
seal or otherwise, all such written proxies or other instruments as he may deem
necessary or proper in the premises.

                                     ARTICLE VIII

                                      AMENDMENTS

    SECTION 8.1.   AMENDMENTS.  These By-Laws may be altered, amended, or
repealed at any meeting of the Board of Directors or of the stockholders,
provided notice of the proposed change was given in the notice of the meeting
and, in the case of a meeting of the Board of Directors, in a notice given not
less than two days prior to the meeting; provided, however, that, in the case of
amendments by stockholders, notwithstanding any other provisions of these
By-Laws or any provision of law which might otherwise permit a lesser vote or no
vote, but in addition to any affirmative vote of the holders of any particular
class or series of the capital stock of the Corporation required by law, the
Certificate of Incorporation or these By-Laws, the affirmative vote of the
holders of at least a majority of the voting power of all the then outstanding
shares of the Voting Stock, voting together as a single class, shall be required
to alter, amend or repeal any provision of these By-Laws.


                                         -38-