EXHIBIT 2 








                          AGREEMENT AND PLAN OF MERGER




                                  by and among 




                                Thermedics Inc.,

                                ATI Merger Corp.,

                          Analytical Technology, Inc., 

                                      and, 
                          for certain limited purposes,

                         Thermo Instrument Systems Inc.





                          Executed on November 29, 1995
PAGE








                          AGREEMENT AND PLAN OF MERGER


             THIS AGREEMENT, dated as of the 29th day of November, 1995,
        by and among Thermedics Inc., a Massachusetts corporation having
        an office at 470 Wildwood Street, P. O. Box 2999, Woburn,
        Massachusetts  01888-1799 ("Thermedics"), ATI Merger Corp., a
        Delaware corporation and a wholly-owned subsidiary of Thermedics
        ("Acquisition"), and Analytical Technology, Inc., a Delaware
        corporation having an office at The Schrafft Center, 529 Main
        Street, Boston, Massachusetts  02129 ("ATI").  Thermo Instrument
        Systems Inc. ("THI") is made a party to this Agreement for
        certain limited purposes pursuant to Section 7.4(a) hereof.

             WHEREAS, ATI's Unicam Technology Limited subsidiary and
        Thermedics have entered into that certain Share Purchase
        Agreement of even date herewith (the "Russell Agreement"),
        pursuant to which Unicam Technology Limited intends to sell to
        Thermedics, and Thermedics intends to purchase from Unicam
        Technology Limited, the capital stock of Russell pH Limited (the
        "Russell Transaction"); 

             WHEREAS, ATI and THI, and certain of their respective
        affiliates, have entered into that certain Asset and Share
        Purchase Agreement of even date herewith (the "THI Agreement"),
        pursuant to which ATI intends to sell to THI, and THI intends to
        purchase from ATI, certain assets and the capital stock of
        certain of ATI's subsidiaries (the "THI Transaction"); and

             WHEREAS, the Boards of Directors of Acquisition and ATI deem
        it advisable and in the best interest of such corporations and
        their respective shareholders that, immediately after giving
        effect to the THI Transaction, Acquisition be merged into and
        with ATI on the terms and conditions set forth in this Agreement,
        as a result of which ATI will become a wholly-owned subsidiary of
        Thermedics; 

             NOW THEREFORE, for and in consideration of the mutual
        covenants and agreements hereinafter set forth, and other good
        and valuable consideration, the receipt and sufficiency of which
        is acknowledged by each party hereto, the parties hereto agree as
        follows:


                                    ARTICLE 1

                                   THE MERGER

             Section 1.1.  Agreement and Plan of Merger.  Effective as of
        the Effective Date (as defined in Section 2.2 below), Acquisition
        shall be merged with and into ATI (hereinafter sometimes called
        the "Merger") in accordance with the terms of this Agreement and
PAGE






        the Certificate of Merger set forth in Exhibit A hereto (the
        "Certificate of Merger").  ATI shall be the corporation surviving
        the Merger (the "Surviving Corporation"), and the separate
        existence of Acquisition shall cease as of the Merger.  The
        Certificate of Incorporation and the Bylaws of ATI, each as
        amended and in effect immediately prior to the Effective Time of
        the Merger (as defined in Section 2.2 below), shall thereafter
        continue in full force and effect as the Certificate of
        Incorporation and Bylaws of the Surviving Corporation.  The
        directors and officers of Acquisition immediately prior to the
        Effective Date shall be, from and after the Effective Date, the
        directors and officers of the Surviving Corporation, each to hold
        office in accordance with applicable law and the Certificate of
        Incorporation and Bylaws of ATI, each as amended.  The effect of
        the Merger shall be as provided by Section 259 of the General
        Corporation Law of the State of Delaware (the "General
        Corporation Law").

             Section 1.2.  Conversion of ATI's Shares and Stock Options.
        At the Effective Time of the Merger, each share of ATI's capital
        stock outstanding immediately prior thereto (herein referred to
        as an "ATI Share" and collectively as the "ATI Shares"), and each
        outstanding option or other right to purchase ATI Shares (herein
        referred to as an "ATI Option" and collectively as the ATI
        Options") by virtue of the Merger and without any action on the
        part of the holder thereof, but subject to this Section 1.2 and
        to Sections 1.3, 1.4, 1.5 and 1.6, below, shall be canceled and
        converted into the right to receive, in cash, an amount equal to
        such holder's pro rata share (the "Pro Rata Share") of
        $79,284,183 (as adjusted pursuant to the terms of Section 1.3 and
        reduced pursuant to the terms of Section 1.6, the "Purchase
        Price").  The Pro Rata Share of each holder of ATI Shares and/or
        ATI Options shall be equal to a fraction, the numerator of which
        shall be the sum of (i) the number of ATI Shares held by such
        holder plus (ii) the number of ATI Shares issuable upon the
        exercise of all ATI Options held by such holder, and the
        denominator of which shall be the sum of (x) the number of ATI
        Shares outstanding immediately prior to the Effective Time plus
        (y) the number of ATI Shares issuable upon the exercise of all
        ATI Options outstanding immediately prior to the Effective Time.
        For the purpose of this Agreement, the term "Per Share Amount"
        shall mean an amount equal to the Purchase Price divided by the
        sum of (x) and (y) in the next preceding sentence.  

             Section 1.3.  Adjustments to Purchase Price.

                  (a)  Within 10 business days after the Closing Date (as
        defined in Section 2.1 below), Thermedics shall cause ATI to
        prepare a consolidated balance sheet of ATI and its subsidiaries,
        as of the close of ATI's fiscal month next preceding the Closing
        Date but without giving effect to the THI Transaction or to any
        other transaction specifically contemplated by this Agreement
        (the "Closing Balance Sheet"), which Closing Balance Sheet shall
        be subject to review by a single party (the "Shareholder

                                        2
PAGE






        Representative") designated collectively by all of the holders of
        ATI Shares and ATI Options (collectively, the "Shareholders")
        pursuant to Section 1.9 below, for and on behalf of the
        Shareholders.  The Purchase Price shall then be either (i)
        increased by the amount by which the Net Tangible Equity of ATI
        (as defined below) as calculated from the Closing Balance Sheet
        exceeds a deficit of $1,989,000; or (ii) decreased by the amount
        by which a deficit of $1,989,000 exceeds the Net Tangible Equity
        of ATI as calculated from the Closing Balance Sheet (such amount,
        as the case may be, the "Closing Price Adjustment").  The Closing
        Balance Sheet shall be prepared using the same accounting
        principles used in preparing ATI's balance sheet as of July 1,
        1995, attached hereto as Exhibit B.  To the extent practicable,
        the Closing Balance Sheet shall be prepared by the same
        individuals who closed ATI's books in connection with the
        preparation of such balance sheet as of July 1, 1995.  Thermedics
        agrees that it shall not permit ATI to terminate the employment
        of such persons, except for cause, until after they have prepared
        the Closing Balance Sheet.

                  (b)  For purposes of this Agreement, the term "Net
        Tangible Equity of ATI" shall be determined in accordance with
        generally accepted accounting principles consistently applied by
        ATI and shall be defined as (i) the consolidated shareholders'
        equity of ATI and its subsidiaries as set forth on the Closing
        Balance Sheet, less (ii) the amount of any goodwill set forth on
        the Closing Balance Sheet, and (iii) the value of any capitalized
        intangible assets reflected on the Closing Balance Sheet.

                  (c)   Thermedics shall provide the Shareholder
        Representative with a copy of the Closing Balance Sheet promptly
        upon the completion thereof, and shall provide the Shareholder
        Representative and its accountants and advisors with access
        (during Thermedics' normal business hours and upon reasonable
        notice) to all data, workpapers and other information from which
        the Closing Balance Sheet was prepared.  If the Shareholder
        Representative disagrees with the Closing Balance Sheet as
        determined by Thermedics, then Thermedics and the Shareholder
        Representative shall attempt to resolve any discrepancies in good
        faith and on a reasonable schedule.  Thermedics reserves the
        right, however, at its option and at its expense, to cause the
        Closing Balance Sheet to be audited in connection with the audit
        of Thermedics' financial statements for the year ending December
        30, 1995.  The parties agree that in no event shall the Purchase
        Price Adjustment be deemed to be determined unless and until the
        earlier of (i) the completion of such audit of the Closing
        Balance Sheet or (ii) the written waiver by Thermedics of the
        requirement of such an audit.

                  (d)  If the parties are unable to agree on the Closing
        Balance Sheet or the Closing Price Adjustment by the close of
        business on the 30th day after the date of the audit report with
        respect to Thermedics' financial statements for the year ended
        December 30, 1995, then the parties shall retain a nationally

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        recognized accounting firm (which shall not be Ernst & Young LLP
        or Arthur Andersen LLP) to resolve any dispute between them and
        the Closing Balance Sheet and the Closing Price Adjustment
        determined by such accounting firm shall be binding upon the
        parties.  Thermedics shall pay one-half of such accounting firm's
        fees and expenses, and the other half of such fees and expenses
        shall be paid by the Shareholder Representative.

             Section 1.4.  Dissenting Shares.  Each outstanding ATI Share
        held by an ATI shareholder who has demanded and perfected his
        right to an appraisal of his ATI Shares in accordance with
        Section 262 of the General Corporation Law and who has not
        effectively withdrawn or lost his right to such appraisal
        ("Dissenting Shares") shall not be converted into or represent
        the right to receive his Pro Rata Share of the Purchase Price
        represented by such ATI Shares pursuant to Section 1.2 above, but
        the holder thereof shall be entitled only to such rights as are
        granted by Section 262 of the General Corporation Law.  

             Section 1.5.  Escrow Account.  For the purpose of providing
        support of the representations and warranties of ATI contained
        herein, to provide a fund from which any Purchase Price
        Adjustment in favor of Thermedics may be paid, and to induce
        Thermedics to enter into this Agreement, $5,000,000 shall be
        withheld from the payment of the Purchase Price at the Closing
        and shall be set aside in escrow (the "Escrow Account") pursuant
        to the terms of an Indemnification and Escrow Agreement to be
        entered into at the Closing by and among Thermedics, THI, ATI,
        the Shareholder Representative and BayBank N.A., as escrow agent,
        in substantially the form of Exhibit C hereto (the "Escrow
        Agreement").  The funds placed in escrow pursuant to this Section
        1.5, together with any interest or earnings thereon, shall be
        considered the "Escrowed Funds."  The Escrowed Funds shall be
        held as a trust fund and shall not be subject to any lien,
        attachment, trustee process or any other judicial process of any
        creditor of any party, and shall be held and disbursed by the
        Escrow Agent solely for the purposes and in accordance with the
        terms of the Escrow Agreement.    

             Section 1.6.  Disbursement of the Purchase Price and the
        Closing Price Adjustment.  

                  (a)  Appointment of Paying Agent.  Prior to the Closing
        Date, Thermedics and ATI shall mutually select a bank or trust
        company to act as paying agent (the "Paying Agent") pursuant to
        an Agency Agreement (the "Agency Agreement") in form and
        substance reasonably satisfactory to Thermedics and ATI, which
        Agency Agreement shall provide for the payment of the Purchase
        Price (as reduced pursuant to Section 1.6(b) below) upon
        surrender of certificates representing outstanding ATI Shares and
        agreements representing the right to exercise outstanding ATI
        Options to be converted into the right to receive cash pursuant
        to the Merger and for the payment of amounts received from the
        Escrow Agent pursuant to the Escrow Agreement. 

                                        4
PAGE







                  (b)  The Purchase Price shall be disbursed following
        the Effective Time as follows:  on the Closing Date, (i)
        $5,000,000 shall be paid by Thermedics (at the direction and on
        behalf of the Shareholders) into the Escrow Account pursuant to
        Section 1.5 hereof, (ii) $350,000 shall be paid by Thermedics (at
        the direction and on behalf of ATI) to Sonnenschein Nath &
        Rosenthal in payment of all legal fees and expenses incurred or
        to be incurred by ATI in connection with the transactions
        contemplated by this Agreement and which have not been paid as of
        the Closing, (iii) $1,041,146 shall be paid by Thermedics (at the
        direction and on behalf of ATI) to CS First Boston Incorporated
        in payment of all professional or transactional fees and expenses
        incurred or to be incurred by ATI in connection with the
        transactions contemplated by this Agreement and which have not
        been paid as of the Closing, (iv) $500,000 shall be paid by
        Thermedics (on behalf of the Shareholders to the Paying Agent for
        the account of the Shareholder Representative in payment of the
        fees and expenses thereof, and (v) the balance of the Purchase
        Price (the "Balance") shall be paid by Thermedics as follows:
        (A) an amount equal to the product of the Balance and a fraction,
        the numerator of which is the number of ATI Shares outstanding
        immediately prior to the Effective Time and the denominator of
        which is the sum of the number of ATI Shares plus the number of
        ATI Shares issuable upon the exercise of all ATI Options
        outstanding immediately prior to the Effective Time (the
        "Shareholders' Payment") shall be paid to the Paying Agent for
        the account of the holders of ATI Shares outstanding immediately
        prior to the Effective Time and (B) an amount equal to the
        remainder of the Balance minus the Shareholder Payment (the
        "Option Payment") shall be paid to ATI for the account of the
        holders of ATI Shares and ATI Options immediately prior to the
        Effective Time.  Immediately following the Effective Time
        Thermedics shall cause ATI to pay to the Paying Agent, from the
        Option Payment, (X) for the account of the holders of ATI Shares
        and ATI Options immediately prior to the Effective Time, an
        amount equal to the aggregate exercise price of all ATI Options
        outstanding immediately prior to the Effective Time (the
        "Exercise Price") and (Y) for the account of the holders of ATI
        Options immediately prior to the Effective Time, an amount equal
        to the remainder of the Option Payment minus the Exercise Price
        (the "Optionholders' Payment").

                  (c)  As soon as practicable after the Effective Time,
        and in accordance with the Agency Agreement, the Paying Agent
        shall mail to (i) each holder of record of a certificate or
        certificates which immediately prior to the Effective Time
        represented outstanding ATI Shares (the "Certificates"), other
        than ATI and any subsidiary of ATI, and (ii) each party to a
        written agreement which immediately prior to the Effective Time
        represented an ATI Option (the "Option Agreements") the
        following:  (i) a letter of transmittal (which shall specify that
        delivery shall be effected, and risk of loss and title to the
        Certificates and the Option Agreements shall pass, only upon

                                        5
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        delivery of the Certificates and the Option Agreements to the
        Paying Agent and shall be in such form and have such other
        provisions as Thermedics may reasonably specify), (ii)
        instructions for use in effecting the surrender of the
        Certificates and the Option Agreements in exchange for such
        holder's or person's Pro Rata Share, and (iii) a Shareholder
        Representative Agency Agreement in form and substance
        satisfactory to ATI (the "Shareholder Representative Agency
        Agreement") pursuant to which a holder of ATI Shares shall
        appoint the Shareholder Representative to act on its behalf with
        respect to the Escrow Agreement and the Agency Agreement.  Upon
        surrender of a Certificate or an Option Agreement (or affidavit
        of lost Certificate or Option Agreement, as the case may be, in
        form and substance reasonably satisfactory to Thermedics and
        Paying Agent, and, if Thermedics or Paying Agent shall reasonably
        request, the posting of an indemnity bond in form and substance
        reasonably satisfactory to Thermedics and Paying Agent) to the
        Paying Agent or to such other agent or agents as may be appointed
        by the Surviving Corporation, together with such letter of
        transmittal, duly executed, a duly executed Stockholders
        Representative Agency Agreement and such other documents as may
        be required by the Paying Agent, the holder of such Certificate
        or Option Agreement shall be entitled to receive in exchange
        therefor (A) the holder of each Certificate shall receive an
        amount equal to the product of the Per Share Amount and the
        number of ATI Shares held by such holder immediately prior to the
        Effective Time, (B) the holder of each Option Agreement shall
        receive, for the account of ATI from the Optionholders' Payment,
        an amount equal to the product of the Per Share Amount and the
        number of ATI Options held by such holder immediately prior to
        the Effective Time, minus the aggregate exercise price of such
        ATI Options, and (C) the holder of each Certificate and the
        holder of each Option Agreement shall receive, from the Exercise
        Price, an amount equal to the product of the Exercise Price and a
        fraction (the "Ownership Percentage"), the numerator of which is
        the sum of all ATI Shares and all ATI Options held by such
        holder, and the denominator of which is the sum of all ATI Shares
        and all ATI Options held by all holders, in each case immediately
        prior to the Effective Time and in each case less any amounts
        required to be withheld under applicable federal, state, local or
        foreign income tax regulations; and the Certificates and Option
        Agreements so surrendered shall forthwith be canceled or
        terminated, as the case may be.  No interest will be paid or will
        accrue on the cash payable upon the surrender of any Certificate
        or Option Agreement.  In the event of a transfer of ownership of
        ATI Shares which is not registered in ATI's transfer records, a
        check in payment of the proper amount of cash may be issued to a
        transferee if the Certificate representing such ATI Shares is
        presented to the Paying Agent, accompanied by all documents
        required to evidence and effect such transfer and by evidence
        that any applicable stock transfer taxes have been paid.  Until
        surrendered as contemplated by this Section 1.6(c), each
        Certificate and each Option Agreement shall be deemed at any time
        after the Effective Time to represent only the right to receive

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        upon such surrender, but subject to the terms of Section 1.5
        hereof and to the Escrow Agreement, the amount of cash specified
        in Section 1.2 and any amounts received by the Paying Agent from
        the Escrow Agent pursuant to the Escrow Agreement; provided,
        however, that unless and until any such outstanding Certificate
        is so surrendered (or an affidavit of lost or destroyed
        Certificate and satisfactory indemnity bond is provided), the
        holder of such outstanding Certificate shall cease to have any
        rights as a Shareholder, except such rights, if any, as such
        holder may have with respect to Dissenting Shares, and, except as
        set forth above, shall not be entitled to receive any
        consideration from the Surviving Corporation and/or Thermedics
        with respect to the ATI Shares represented by such Certificate.
        Any funds deposited with the Paying Agent that are payable to a
        former Shareholder which has not submitted a claim for its Pro
        Rata Share as described in this Section 1.6(c) within one year
        after the Effective Time shall be paid to the Surviving
        Corporation upon demand, and any former Shareholders who have not
        theretofore complied with the instructions for exchanging their
        Certificates and/or Option Agreements shall thereafter look only
        to the Surviving Corporation for payment, it being acknowledged
        by Thermedics and Acquisition that the receipt of any such
        amounts by the Surviving Corporation shall not relieve it of its
        payment obligations to such former Shareholders.  After the
        Effective Time, (i) except for transfers of Dissenting Shares in
        accordance with Section 262 of the General Corporation Law, there
        shall be no transfers on ATI's stock transfer books of the ATI
        Shares which were outstanding immediately prior to the Effective
        Time and (ii) no further exercises of ATI Options shall be
        permitted.  

                  (d)  Payment of a Closing Price Adjustment by
        Thermedics, if any, shall be made to the Paying Agent (for
        distribution to the former holders of ATI Shares and ATI Options)
        as follows:  to each of the holders of ATI Shares and ATI Options
        immediately prior to the Effective Time, after delivery of the
        documents required pursuant to paragraph (c) of Section 1.6
        hereof, an amount equal to the product of the Closing Price
        Adjustment and such holder's Ownership Percentage.  Payment of a
        Closing Price Adjustment to Thermedics, if any, shall be made
        from and out of the Escrowed Funds pursuant to the Escrow
        Agreement, and the former holders of ATI Shares and ATI Options
        shall have no obligation therefor in excess of their pro rata
        shares of the Escrowed Funds.

             Section 1.7.  Conversion of Acquisition Shares.  On the
        Effective Date, each share of Acquisition's common stock
        outstanding immediately prior thereto shall, by virtue of the
        Merger and without any action on the part of the holder thereof,
        be canceled and converted into one fully paid and nonassessable
        common share of the Surviving Corporation, which share shall be
        registered in the name of and beneficially owned by Thermedics.



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             Section 1.8.  Adoption by Shareholders.  This Agreement
        shall be promptly submitted to the shareholders of Acquisition
        and ATI as provided by law.  In the case of Acquisition,
        Thermedics, as its sole shareholder, shall vote all its shares in
        favor of adoption of this Agreement.  In the case of ATI, this
        Agreement shall be promptly submitted to the Shareholders for
        their approval pursuant to the General Corporation Law.  The
        Board of Directors of ATI shall recommend to the Shareholders the
        approval of this Agreement and the Merger.

             Section 1.9.  Appointment of Shareholder Representative.   
        At the Effective Time, and without any further action on the part
        of the holders of the ATI Shares or the holders of the ATI
        Options, the Shareholder Representative shall be deemed to have
        been appointed as the representative and agent of the holders of
        the ATI Shares and the holders of the ATI Options as contemplated
        hereby and under the Escrow Agreement, which appointment may be
        ratified by any or all holders of the ATI Shares and the holders
        of the ATI Options pursuant to the Shareholder Representative
        Agency Agreement (as hereinafter defined); provided, however,
        that the failure to execute and deliver the Shareholder
        Representative Agency Agreement will not alter the rights of the
        Shareholder Representative hereunder and under the Escrow
        Agreement.


                                    ARTICLE 2

                                     CLOSING

             Section 2.1.  Time and Place of Closing.  The closing under
        this Agreement (herein called the "Closing") shall take place at
        the offices of Thermo Electron Corporation, 81 Wyman Street,
        Waltham, Massachusetts  02254 at 10:00 a.m., local time, on the
        day of the later of (i) the approval by the Shareholders of the
        execution, delivery and performance by ATI of this Agreement and
        (ii) the satisfaction of all other conditions to Closing as set
        forth in Article 5 hereof, or at such other time or date as may
        be mutually agreeable to the parties hereto (the date on which
        the Closing occurs being herein called the "Closing Date").  All
        transactions at the Closing shall be deemed to take place
        simultaneously and no transaction shall be deemed to have been
        completed and no document or certificate shall be deemed to have
        been delivered until all transactions are completed and all
        documents delivered.

             Section 2.2.  Consummation of the Merger.  As soon as is
        practicable after the satisfaction or waiver of the conditions
        set forth in Article 5 hereof, the parties hereto will cause the
        Merger to be consummated by delivering to the Secretary of State
        of the State of Delaware the Certificate of Merger in such form
        as may be required by, and executed and acknowledged in
        accordance with, the relevant provisions of the General
        Corporation Law.  The Merger shall become effective upon the date

                                        8
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        (the "Effective Date") and at the time (the "Effective Time") of
        the filing of the Certificate of Merger with such Secretary of
        State, or at such later time, which shall be as soon as
        reasonably practicable, specified as the Effective Date in the
        Certificate of Merger. 


                                    ARTICLE 3

                         REPRESENTATIONS AND WARRANTIES

             Section 3.1.  Definitions.  Unless and except to the extent
        expressly indicated otherwise, when used in Section 3.2 of this
        Agreement:

                  (a)  The term "Subsidiary" shall mean each entity of
        which fifty percent (50%) or more of the effective voting power
        or equity interest is owned directly or indirectly (whether
        legally or beneficially) by ATI.

                  (b)  The term "Acquired Companies" shall mean ATI and
        its current Subsidiaries (and, notwithstanding the consummation
        of the Russell Transaction, Russell pH Limited), taken as a whole
        or individually as the context requires.  

                  (c)  The term "knowledge," as it relates to ATI and the
        Acquired Companies, shall mean actual knowledge of the following
        executive officers of ATI:  William J. Kennedy, Robert E. Kinney
        and Chane Graziano, or of any of the foregoing, in each case
        after actually conducting a reasonable and diligent
        investigation.

                  (d)  The term "basis" shall mean any past or present
        fact, situation, circumstance, status, condition, activity,
        practice, plan, occurrence, event, incident, action, failure to
        act or transaction known to the party making the representation
        or warranty that forms or should reasonably be expected to form
        the basis for any specified consequence.  

                  (e)  The term "ordinary course of business" shall mean
        the ordinary course of business of any Acquired Company
        consistent with its past custom and practice (including with
        respect to frequency and amount).  

                  (f)  The term "Code" shall mean the Internal Revenue
        Code of 1986, as amended and in effect.

                  (g)  The term "generally accepted accounting
        principles" shall mean, as it applies to any Acquired Company,
        the accounting principles generally recognized as appropriate in
        the jurisdiction in which such Acquired Company is organized, and
        applied on a basis consistent with the past practice of such
        Acquired Company.


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             Section 3.2.   Representations and Warranties Pertaining to
        ATI.  ATI represents and warrants to Thermedics and Acquisition
        that, except as set forth on the disclosure schedule attached
        hereto as Exhibit D (specifically identifying the relevant
        subsection hereof) (the "Disclosure Schedule"):

                  (a)  Organization and Qualification.  ATI is a
        corporation duly organized, validly existing and in good standing
        under the laws of the State of Delaware and has all requisite
        corporate power and authority to own, operate and lease its
        properties and to carry on its business as it is now being
        conducted.  ATI is duly qualified as a foreign corporation to do
        business, and is in good standing, in each jurisdiction in which
        the character of the properties owned, operated or leased by it
        or the nature of its activities is such that such qualification
        is required by applicable law.  Each such jurisdiction is set
        forth on the Disclosure Schedule.  Each Subsidiary is a
        corporation or other form of limited liability company duly
        incorporated or otherwise duly organized, validly existing and in
        good standing (in such jurisdictions where such concept is
        applicable) under the laws of its respective jurisdiction of
        incorporation or organization as set forth on the Disclosure
        Schedule.  Each Subsidiary has all requisite corporate and other
        power and authority to own, operate, and lease its properties and
        to carry on its business as it is now being conducted.  Each
        Subsidiary is duly qualified as a foreign corporation to do
        business, and is in good standing, in each jurisdiction in which
        the character of the properties owned, operated or leased by it
        or the nature of its activities is such that such qualification
        is required by applicable law.  Each such jurisdiction is set
        forth on the Disclosure Schedule.  Copies of the Certificate of
        Incorporation and Bylaws of ATI and each Subsidiary have
        heretofore been delivered to Thermedics and such copies are
        accurate and complete in all respects as of the date hereof.

                  (b)  Capitalization.  The authorized capital stock of
        ATI consists of 1,000,000 shares of Series A Preferred Stock,
        $1.00 par value per share ("Preferred Stock"), 6,500,000 shares
        of Common Stock, $.01 par value per share ("Common Stock") and
        3,500,000 shares of Class B Common Stock, $.01 par value per
        share ("Class B Common Stock").  There is no other capital stock
        of ATI authorized for issuance.  As of the date of this
        Agreement: (i) no shares of Preferred Stock, 1,425,887 shares of
        Common Stock and 2,185,105 shares of Class B Common Stock,
        respectively, are issued and outstanding, and such shares
        constitute the total issued and outstanding share capital of ATI,
        all of which have been duly authorized and validly issued, are
        fully paid, nonassessable and free of preemptive rights, and are
        held of record by the Shareholders identified in the Disclosure
        Schedule; (ii) 40,283 shares of Common Stock are held in the
        Treasury of ATI; and (iii) 737,322 shares of Common Stock were
        reserved for issuance pursuant to ATI's 1990 Incentive Stock
        Option Plan, 1994 Incentive Stock Option Plan, and 1994 Directors
        Stock Option Plan (collectively, the "Option Plans").  No stock

                                       10
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        appreciation rights, phantom stock, performance based rights or
        similar equity rights or obligations are outstanding under the
        Option Plans or otherwise.  The Disclosure Schedule sets forth
        (i) the number of shares of Common Stock reserved for issuance or
        grant and actually issued or granted under the Option Plans and
        (ii) the exercise price of each option or other method of
        determining the purchase price for any ATI Shares issued or
        issuable pursuant thereto.  Except as set forth above, there are
        no other shares of capital stock or other securities of ATI
        outstanding and no other outstanding options, warrants, rights to
        subscribe to (including any preemptive rights), calls or
        commitments of any character whatsoever to which ATI or any of
        its Subsidiaries is a party or may be bound requiring the
        issuance, transfer or sale of any shares of capital stock or
        other securities of ATI or any of its Subsidiaries or any
        securities or rights convertible into or exchangeable or
        exercisable for any such shares or securities, and there are no
        contracts, commitments, understandings or arrangements by which
        ATI or any of its Subsidiaries is or may become bound to issue
        additional shares of their capital stock or options, warrants or
        rights to purchase or acquire any additional shares of their
        capital stock or securities convertible into or exchangeable or
        exercisable for any such shares.  To ATI's knowledge, none of the
        ATI Shares is subject to any voting trust, transfer restrictions
        or other similar arrangements, except for restrictions on
        transfer imposed by the Securities Act of 1933, as amended, and
        state securities laws.

                  (c)  Subsidiaries.  ATI has no Subsidiaries except as
        identified on the Disclosure Schedule.  All of the issued and
        outstanding capital stock of each of such Subsidiaries is owned
        beneficially and of record by ATI.  No Acquired Company is a
        partner or joint venturer with any other person. No Acquired
        Company directly or indirectly owns any equity or similar
        interest in, or any interest convertible into or exchangeable or
        exercisable for, any equity or similar interest in, any other
        corporation, partnership, joint venture or other similar business
        association or entity.  No Acquired Company is subject to any
        obligation, contingent or otherwise, to provide funds to or make
        an investment (in the form of a loan, capital contribution or
        otherwise) in any entity.

                  (d)  Authority.  Subject only to the approval of
        Shareholders holding a majority in voting interest of the ATI
        Shares, ATI has full corporate power and authority to execute,
        deliver and perform this Agreement, to execute, deliver and file
        the Certificate of Merger and to consummate the transactions
        contemplated hereby and thereby.  This Agreement has been duly
        and validly authorized by all necessary corporate action on the
        part of ATI, subject only, in respect of the consummation of the
        Merger, to approval by the Shareholders holding a majority in
        voting interest of the ATI Shares.  The Board of Directors of ATI
        has (i) determined that this Agreement and the transactions
        contemplated hereby, including the Merger, are fair to and in the

                                       11
PAGE






        best interest of the Shareholders, (ii) approved this Agreement
        and the transactions contemplated hereby, including the Merger,
        and (iii) resolved to recommend approval and adoption of this
        Agreement and the Merger by the Shareholders.  This Agreement has
        been duly and validly executed and delivered by ATI and, subject
        only to Shareholder approval, constitutes the valid and binding
        obligation of ATI, enforceable against it in accordance with its
        terms, except to the extent that such enforcement may be subject
        to applicable bankruptcy, insolvency, reorganization, moratorium
        or other similar laws now or hereafter in effect, and except that
        the remedy of specific performance and injunctive and other
        equitable relief may be subject to equitable defenses and to the
        discretion of the court before which any proceeding therefor may
        be brought.  Neither the execution, delivery and performance of
        this Agreement, the filing of the Certificate of Merger nor the
        consummation of the transactions contemplated hereby will (i)
        conflict with or result in a violation, breach, termination or
        acceleration of, or default under (or would result in a
        violation, breach, termination, acceleration or default with the
        giving of notice or passage of time, or both) any of the terms,
        conditions or provisions of the Certificate of Incorporation or
        Bylaws of ATI, as amended, or of any note, bond, mortgage,
        indenture, license, agreement or other instrument or obligation
        to which any Acquired Company is a party or by which any Acquired
        Company or any of its properties or assets may be bound or
        affected; (ii) result in the violation of any order, writ,
        injunction, decree, statute, rule or regulation applicable to any
        Acquired Company or its properties or assets; (iii) result in the
        imposition of any lien, encumbrance, charge or claim upon any of
        the assets of any Acquired Company; or (iv) entitle any employee
        to severance or other payments by any Acquired Company or create
        any other obligation to an employee, including an increase in
        benefits.  Except for (i) the approval by the Shareholders of the
        Merger, (ii) a filing under the Hart-Scott-Rodino Antitrust
        Improvements Act of 1976, as amended (the "Antitrust Improvements
        Act"), (iii) filings under the antitrust or competition laws of
        the jurisdictions identified on the Disclosure Schedule (the
        "Competition Laws"), (iv) filing of the Certificate of Merger
        with the Secretary of State of the State of Delaware, and (v)
        similar filings in jurisdictions in which ATI is qualified as a
        foreign corporation to do business, no consent or approval by, or
        notification to or filing with, any court, governmental authority
        or third party or waiting period imposed by law is required in
        connection with the execution, delivery and performance of this
        Agreement by ATI or the consummation of the transactions
        contemplated hereby.

                  (e)  Financial Statements.  ATI has delivered to
        Thermedics prior to the execution of this Agreement true and
        complete copies of (i) the audited consolidated balance sheets of
        ATI as at December 31, 1994, January 1, 1994 and January 2, 1993,
        and audited consolidated statements of earnings and cash flows
        for the years ended December 31, 1994, January 1, 1994 and
        January 2, 1993, accompanied by the report thereon by Ernst &

                                       12
PAGE






        Young LLP, and (ii) the unaudited consolidated balance sheet of
        ATI as at September 30, 1995 (the "Pre-Closing Balance Sheet")
        and the unaudited statements of earnings and cash flows for the
        nine months ended September 30, 1995 (all of the financial
        statements referred to in this Section 3.2(e), collectively, the
        "Financial Statements").  The audited balance sheet as at
        December 31, 1994 and the Pre-Closing Balance Sheet fairly
        present the financial condition of ATI as at their respective
        dates, subject in the case of the Pre-Closing Balance Sheet to
        normal year-end adjustments, and the other Financial Statements
        fairly present the financial condition, results of operations and
        cash flows of ATI as at the dates and for the periods indicated,
        in each case in accordance with generally accepted accounting
        principles applied on a basis consistent with previous years.
        Since the date of the Pre-Closing Balance Sheet, there has been
        no material adverse change in the financial condition, assets,
        liabilities, earnings, business or prospects of ATI.
               
                  (f)  No Undisclosed Liabilities.  To ATI's knowledge,
        no Acquired Company has any liabilities or obligations of any
        nature, other than those shown on the Pre-Closing Balance Sheet,
        those which have arisen after the date of the Pre-Closing Balance
        Sheet in the ordinary course of business which are not in the
        aggregate or individually material and those which may result
        directly or indirectly from the transactions contemplated by this
        Agreement and by the Russell Agreement or the THI Agreement.  As
        used in this paragraph (f), the term "liability" includes any
        indebtedness, claim, loss, damage, deficiency (including deferred
        income tax), cost, expense, guaranty or responsibility, whether
        absolute or contingent, accrued or unaccrued, liquidated or
        unliquidated, asserted or unasserted, due or to become due, or
        otherwise.  The Disclosure Schedule sets forth in detail the
        calculation of all amounts paid or payable by any person with
        respect to the termination of the Employment Agreements dated as
        of January 16, 1995 with each of Messrs. William J. Kennedy,
        Robert E. Kinney and Chane Graziano (the "Employment
        Agreements").

                  (g)  Tax Matters.  

                       (i)  For purposes of this Agreement, "Tax" means
             any federal, state, provincial, local or foreign income,
             gross receipts, license, payroll, employment, excise,
             severance, stamp, occupation, premium, windfall profits,
             environmental (including without limitation Taxes under Code
             Section 59A), customs duties, capital stock, franchise,
             profits, withholding, social security (or similar),
             unemployment, disability, real property, personal property,
             sales, use, transfer, registration, value added, alternative
             or add-on minimum, estimated, or other tax or other fiscal
             charges of any kind whatsoever, including without limitation
             any interest, penalty, or addition thereto, whether disputed
             or not (but excluding any tax attributable to the THI


                                       13
PAGE






             Transaction or to the transactions contemplated by this
             Agreement).

                       (ii)  For purposes of this Agreement, "Tax Return"
             means any return, declaration, report, claim for refund, or
             information return or statement relating to Taxes, including
             without limitation any schedule or attachment thereto, and
             any amendment thereof.

                       (iii)  Each Acquired Company has accurately
             prepared and duly and timely filed all Tax Returns that it
             was required to file.  Except as set forth on the Disclosure
             Schedule, all such Tax Returns were correct and complete in
             all material respects.  All Taxes owed by each such Acquired
             Company as reflected on the Tax Returns have been paid when
             due, other than those being contested in good faith and
             where adequate reserves have been established therefor.  No
             Acquired Company is currently the beneficiary of any
             extension of time within which to file any Tax Return.  To
             ATI's knowledge, no claim or inquiry with respect to any
             material amount of Taxes has ever been made by an authority
             in a jurisdiction where an Acquired Company did not file Tax
             Returns that it is or may be subject to any Tax by that
             jurisdiction for any period ending on or before the Closing
             Date.  There are no liens or other security interests on any
             of the assets of any Acquired Company that arose in
             connection with any failure (or alleged failure) to pay any
             Tax.

                       (iv)  Except as set forth in the Disclosure
             Schedule, to ATI's knowledge, no Acquired Company has ever
             filed a consolidated return with a company other than an
             Acquired Company.

                       (v)  ATI has delivered to Thermedics true and
             complete copies of the Acquired Companies' tax returns as
             identified on the Disclosure Schedule.

                       (vi)  All Taxes of the Acquired Companies
             attributable to Tax periods or portions thereof ending on or
             prior to the Effective Date, including Taxes that may become
             payable by any Acquired Company in future periods in respect
             of any transactions or sales occurring on or prior to the
             Effective Date, that have not yet been paid have, in the
             aggregate, been adequately reflected as a liability on the
             books of the Acquired Companies (including the Financial
             Statements) in accordance with generally accepted accounting
             principles consistently applied.

                       (vii)  Without limiting the generality of the
             foregoing, each Acquired Company has withheld or collected
             and duly paid all Taxes required to have been withheld or
             collected and paid in connection with payments to foreign
             persons, sales and use Tax obligations with respect to any

                                       14
PAGE






             and all states, and amounts paid or owing to any employee,
             independent contractor, creditor, stockholder or other
             person.

                       (viii)  To ATI's knowledge, none of the Tax
             Returns of any Acquired Company have been or are being
             currently audited or examined by any governmental authority.
             No deficiencies for any Tax have been asserted against any
             Acquired Company.  

                       (ix)  There are no outstanding agreements or
             waivers extending the statute of limitations applicable to
             any Tax Return of any Acquired Company for any period.

                       (x)  No Acquired Company has filed a consent under
             Code Section 341(f) concerning collapsible corporations.  No
             Acquired Company has made any payments, is obligated to make
             any payments, or is a party to any agreement that could
             reasonably be expected to obligate it to make any payments,
             that will be an "excess parachute payment" under Code
             Section 280G.  No Acquired Company has been a United States
             real property holding corporation within the meaning of Code
             Section 897(c)(2) during the applicable period specified in
             Code Section 897(c)(1)(A)(ii).  No Acquired Company has been
             a passive foreign investment company as defined in Code
             Sections 1291-1297.  No Acquired Company is a party to any
             Tax allocation or sharing agreement.  ATI has no liability
             for any Taxes of any person (other than an Acquired Company)
             under Treas. Reg. Section 1.1502-6 (or any similar provision
             of federal, state, provincial, local, or foreign law), as a
             transferee or successor, by contract, or otherwise.

                  (h)  Properties; Environmental, Health and Safety
        Matters.  Each Acquired Company has good title to, or a valid and
        continuing leasehold interest in, all properties and assets, real
        and personal, reflected on the Pre-Closing Balance Sheet or
        acquired by such Acquired Company since the date of the
        Pre-Closing Balance Sheet (except personal property leases
        terminated, or personal property sold or otherwise disposed of,
        in the ordinary course of business since the date of the
        Pre-Closing Balance Sheet), free and clear of all mortgages,
        liens, attachments, pledges, encumbrances or security interests
        of any nature whatsoever, except for liens for taxes not yet due
        and the rights of any lessor under any lease to which such
        Acquired Company is a party.  All leases pursuant to which any
        Acquired Company leases real or personal property are in good
        standing, and are valid and in full force and effect in
        accordance with their respective terms.  There are no defaults
        under any such leases attributable to any Acquired Company, and,
        to ATI's knowledge, no event has occurred that (whether or not
        with notice, lapse of time or both) would constitute a default.
        All buildings, improvements, machinery, equipment, vehicles and
        items of tangible personal property used in connection with the
        operations of the Acquired Companies are in good operating

                                       15
PAGE






        condition and repair, are adequate for the uses to which they are
        being put and, to ATI's knowledge, are not in need of maintenance
        or repairs except for ordinary, routine maintenance.

                  The Disclosure Schedule sets forth or describes in
        reasonable detail with respect to all real property currently
        owned by the Acquired Companies (the "Property"), all other real
        property currently leased by any Acquired Company and, to ATI's
        knowledge, all other real property owned or leased by any
        Acquired Company at any time since January 1, 1990:

                       (i)  (a) landfills, surface impoundments, pits,
             ponds, lagoons, underground injection wells, waste piles,
             land treatment units, incinerators and any other units used
             by any Acquired Company for the treatment, recycling, reuse,
             storage and disposal (hereinafter "Management") of wastes or
             recyclable materials and (b) all underground, in-ground or
             on-ground storage tanks on any such real property;

                       (ii)  for all units identified in clause (i)(a),
             information on the time period used, type of waste or
             recyclable material, method of Management, and whether there
             is any evidence of releases of pollutants or contaminants
             from such units onto the ground or subsurface or into
             groundwater or surface waters;

                       (iii)  for all tanks identified in clause (i)(b),
             information on the time period used, material being stored,
             and when and what tests, if any, have been conducted
             regarding tank integrity and test results, and whether there
             is any evidence of releases of material from such units onto
             the ground or subsurface or into groundwater or surface
             waters;

                       (iv)  any evidence, including sample results, of
             soil or groundwater contamination on or migrating from any
             such real property which is not addressed by clauses (ii) or
             (iii);

                       (v)  a list of all sites to which wastes or
             recyclable materials have been sent by any Acquired Company
             for Management since January 1, 1990, the owner or operator
             of such off-site facilities, the transporter of such wastes
             or recyclable materials, type of waste or recyclable
             materials, method of Management used, and time period of
             use;

                       (vi)  reports of releases (including continuous
             release reports) of hazardous substances or oil occurring on
             or from facilities of any Acquired Company and reported to
             (A) the National Response Center, State Emergency Response
             Commissions, Local Emergency Planning Committees or the
             United States Environmental Protection Agency (the "EPA")
             pursuant to requirements of the Comprehensive Environmental

                                       16
PAGE






             Response, Compensation and Liability Act of 1980, as amended
             by the Superfund Amendments and Reauthorization Act of 1986
             ("CERCLA"), the Resource Conservation and Recovery Act
             ("RCRA"), the Clean Water Act ("CWA") or other federal
             statutes; or (B) any foreign, state, provincial or local
             governmental authority;

                       (vii)  instances of material noncompliance by any
             Acquired Company since January 1, 1990 with conditions of
             environmental permits or licenses issued pursuant to, or
             other requirements of, the Clean Air Act, CWA, RCRA, the
             Toxic Substances Control Act ("TSCA"), the Safe Drinking
             Water Act, CERCLA or similar foreign, state, provincial or
             local statutes, laws, ordinances, rules or regulations
             (including, without limitation, the following United Kingdom
             statutes:  the Clean Air Acts 1956 and 1968; the Control of
             Pollution Act 1974; the Health and Safety at Work etc Act
             1974; the Water Act 1989; and the Environmental Protection
             Act 1990; and all statutory instruments, regulations and
             orders made under each of the foregoing);

                       (viii)  Hazardous Waste Manifest Discrepancy
             Reports, RCRA biennial reports or similar state reports,
             Discharge Monitoring Reports, air emission monitoring
             reports and air emission inventories, filed by any Acquired
             Company with any government agency since January 1, 1990;

                       (ix)  reports of environmental audits conducted
             since January 1, 1990 at facilities owned or leased by any
             Acquired Company, whether by ATI or by consultants, or by
             insurance companies or governmental agencies and made
             available to ATI, and action plans and progress reports
             responding to audit findings;

                       (x)  claims, litigation and other legal
             proceedings against any Acquired Company (including but not
             limited to notices of violation, notices of noncompliance,
             citations, orders, consent orders, consent decrees and
             administrative or judicial enforcement proceedings) seeking
             or alleging money damages (resulting from injury to person
             or property), injunctive relief, remedial action, fines,
             penalties or any other remedy by reason of: (A) violation of
             or noncompliance with any law, regulation, rule or
             requirement of law or regulation relating to pollution or
             protection of the environment ("Environmental Laws"), or any
             permit, license or registration issued thereunder; (B) the
             disposal, discharge or release of solid wastes, pollutants
             or hazardous substances, whether or not in compliance with
             Environmental Laws; (C) the ownership, operation or use of
             any landfill, surface impoundment, pit, pond, lagoon,
             underground injection well, waste pile, land treatment unit,
             wastewater treatment plant, air pollution control equipment,
             or any other unit used for Management of waste or recyclable
             material; or (D) exposure to any chemical substances,

                                       17
PAGE






             noises, odors, or vibration at or emanating from any real
             property which has been or is currently owned or leased by
             any Acquired Company; including in each case all legal
             proceedings which have been concluded (e.g., a judgment or
             consent decree has been entered) but pursuant to which work
             is ongoing (e.g., a decree requiring remedial activity to be
             undertaken);

                       (xi)  all environmentally related permits and
             licenses and pending applications for such permits and
             licenses for facilities which are currently owned or leased
             by any Acquired Company.  For facilities located in the
             United States, this item includes notifications to
             governmental agencies required by Sections 3010(a) (notice
             of hazardous waste activity) and 9002 (underground storage
             tanks) of RCRA and by comparable state laws, and notices and
             reports required pursuant to Sections 302, 311, 312 and 313
             of Title III of the Superfund Amendments and Reauthorization
             Act of 1986 and comparable state laws;

                       (xii)  all current and expired or terminated
             contracts involving the off-site transportation or
             Management of wastes or recyclable materials generated by
             any Acquired Company since January 1, 1990;

                       (xiii)  all reports of environmental assessments,
             surveys or analyses addressing the operational safety of
             facilities and/or activities (e.g., transportation) of any
             Acquired Company and/or hazards and risks (including risk of
             episodic releases and impact of routine, continuous
             releases) associated therewith, including but not limited to
             process risk surveys, operational safety surveys, air
             emissions modeling, and risk assessments, and action plans
             and progress reports responding to any such reports;

                       (xiv)  a description of the manner in which
             asbestos was or is used or otherwise present at any facility
             located on real property which is currently owned or leased
             by any Acquired Company; and

                       (xv)  a list of all governmental inspections since
             January 1, 1990 relating to the environment of facilities
             located on real property which has been or is currently
             owned or leased by any Acquired Company and any reports or
             studies generated therewith.

                  Except as set forth in the Disclosure Schedule:

                       (i)  No Acquired Company is or has been in
             material violation of any law, regulation or ordinance
             (including without limitation, Environmental Laws and laws,
             regulations or ordinances relating to building, health code,
             zoning, land use or similar matters) relating to properties


                                       18
PAGE






             or facilities owned or leased by any Acquired Company since
             January 1, 1990;

                       (ii)  To ATI's knowledge, neither the Property nor
             any other real property currently or previously owned or
             leased by any Acquired Company (A) has ever been the subject
             of environmental clean-up or remediation, or (B) contains
             any Hazardous Material (as defined below) (other than
             Hazardous Materials in quantities not in excess of amounts
             reasonably required by the Acquired Companies in the
             ordinary course of their business), nor has any Hazardous
             Material been discharged or spilled thereon;

                       (iii)  To ATI's knowledge, no Acquired Company has
             ever owned or operated a petroleum or hazardous waste
             landfill or any petroleum or other hazardous waste
             treatment, storage or disposal facility;

                       (iv)  To ATI's knowledge, there are no past or
             present events, conditions, circumstances, activities,
             practices, incidents, actions or plans of any Acquired
             Company which may interfere with or prevent continued
             compliance with Environmental Laws, or which may give rise
             to any common law or legal liability, or otherwise form the
             basis of any claim, action, suit, proceeding, hearing, or
             investigation, based on or related to the disposal, storage,
             handling, manufacture, processing, distribution, use,
             treatment, or transport, or the emission, discharge, release
             or threatened release into the environment, of any pollutant
             or waste;

                       (v)  there are no proceedings affecting the
             Property or, to ATI's knowledge, any other real property
             currently or previously leased by any Acquired Company, or,
             to ATI's knowledge, threatened which could have an adverse
             effect on the present or future use of any such property for
             the purposes for which it was acquired or the purpose for
             which it is used; 

                       (vi)  neither the Property nor, to ATI's
             knowledge, any other real property currently or previously
             leased by any Acquired Company at any time is or has been on
             any federal or state "Superfund" list or on EPA's
             Comprehensive Response, Compensation and Liability
             Information System ("CERCLIS") list or on any analogous
             state environmental agency list; 

                       (vii)  No Acquired Company has received any notice
             from any governmental agency or other party seeking any
             information or alleging any liability with regard to the
             real property occupied or used by such Acquired Company now
             or at any time or with regard to any off-site environmental
             conditions; and 


                                       19
PAGE






                       (viii)  no real property occupied by any Acquired
             Company is subject to a lien under any Environmental Laws.

                  For purposes of this Agreement, "Hazardous Material"
        means any petroleum product or any flammable, explosive or
        radioactive material, or any hazardous or toxic waste, substance
        or material, including substances defined as "hazardous
        substances", "hazardous materials", "solid waste" or "toxic
        substances" under any applicable laws relating to hazardous or
        toxic materials and substances, air pollution (including noise
        and odors), water pollution, liquid and solid waste, pesticides,
        drinking water, community and employee health, environmental land
        use management, stormwater, sediment control, nuisances,
        radiation, wetlands, endangered species, environmental permitting
        and petroleum products, and may include, but not be limited to,
        the Federal Insecticide, Fungicide, and Rodenticide Act, as
        amended; the TSCA; the CWA; the National Environmental Policy
        Act, as amended; the Solid Waste Disposal Act, as amended; the
        CERCLA, as amended; the Clean Air Act, as amended; the Emergency
        Planning and Community Right-to-Know Act, as amended; the
        Occupational Safety and Health Act, as amended; Hazardous
        Materials Transportation Act, as amended; and all rules and
        regulations promulgated pursuant to such federal, state,
        provincial and county and foreign laws and ordinances.

                  (i)  Intellectual Property.  The Disclosure Schedule
        contains a list of all of the following that are owned by any
        Acquired Company: (i) patents and patent applications; (ii)
        registered trademarks, registered trade names and registered
        service marks and applications therefor; and (iii) registered
        licenses relating to any of the foregoing.  The Disclosure
        Schedule identifies the owner of each item listed thereon and, in
        the case of registrations and applications, the application or
        registration number and date.  The Acquired Companies own or have
        the right to use all proprietary rights used in the operation of
        their business as heretofore conducted and necessary to continue
        the operation of such business as heretofore conducted
        (collectively, "Intellectual  Property").  The Acquired Companies
        have taken reasonable measures to protect the proprietary nature
        of the Intellectual Property and to maintain in confidence the
        trade secrets and confidential information that they own or use
        in, and that are material to, their business.  Except as set
        forth on the Disclosure Schedule, no other person or entity has
        any rights to any of the Intellectual Property.  To ATI's
        knowledge, no person or entity is infringing, violating or
        misappropriating any of the Intellectual Property.  Except as set
        forth on the Disclosure Schedule, no Acquired Company has agreed,
        except in the ordinary course of business in conjunction with
        product sales, to indemnify any person or entity for or against
        any infringement, misappropriation or other conflict with any
        Intellectual Property.  The Acquired Companies' use of the
        Intellectual Property in their business does not infringe or
        violate, or constitute a misappropriation of, any intellectual
        property of any other person or entity.  No Acquired Company has

                                       20
PAGE






        received any complaint, claim or notice in writing alleging any
        such infringement, violation or misappropriation, which
        complaint, claim or notice has not been resolved to the mutual
        satisfaction of the parties involved in a manner which involves
        no future obligations of any Acquired Company.  

                  (j)  Governmental Authorizations.  Set forth on the
        Disclosure Schedule is a complete and accurate list of all
        governmental permits, licenses, franchises, concessions, zoning
        variances and other approvals, authorizations and orders which
        have been obtained in connection with, and are material to, the
        conduct of the business now being conducted by each Acquired
        Company.  Such permits, licenses, franchises, concessions, zoning
        variances, approvals, authorizations and orders constitute all
        governmental permits, licenses, franchises, concessions, zoning
        variances, approvals, authorizations and orders which are
        required under all applicable local, state, provincial, federal
        or foreign laws and regulations for the operation of the business
        currently being conducted by ATI and its Subsidiaries and which
        are material to the conduct of such business.  All such permits,
        licenses, franchises, concessions, zoning variances, approvals,
        authorizations and orders are presently in full force and effect,
        each Acquired Company is in material compliance with the
        requirements thereof, no suspension or cancellation of any of
        them is threatened, and the filing of the Certificate of Merger
        and the consummation of the Merger will not adversely affect the
        validity or effectiveness of, and will not require, for retention
        thereof after such change of ownership, the consent or approval
        of any party to, or any other person or governmental agency
        having jurisdiction of, any such permit, license, franchise,
        concession, zoning variance, approval, authorization or order.
        ATI has no knowledge of any fact or circumstance which would
        prevent, limit or restrict any Acquired Company from continuing
        to operate its business in the present manner, and, to ATI's
        knowledge, no new material requirements pertaining to the manner
        of operating its specific business (not businesses in general)
        have been issued or announced by any governmental authority
        during the past year, nor are there any disputes pending between
        any Acquired Company and any governmental authority relating to
        the Acquired Companies' operations as presently being conducted. 

                  (k)  Compliance with Law.  Each Acquired Company has
        complied in all material respects and is in compliance in all
        material respects with all applicable U.S. and foreign laws
        (including without limitation the U.S. Foreign Corrupt  Practices
        Act and the U.S. Occupational Safety and Health Act and
        regulations thereunder), rules, decrees, regulations, ordinances
        and orders ("Laws and Regulations"), including those that affect
        or relate to this Agreement or the transactions contemplated
        hereby.  Each Acquired Company has filed with the proper
        authorities all material statements and reports required by all
        applicable Laws and Regulations relating its business.  No
        Acquired Company has received notice or inquiry relating to any
        actual or alleged violation of any Laws and Regulations.  No

                                       21
PAGE






        Acquired Company is a party to any agreement or arrangement
        (whether or not intended to be legally binding) or is in the
        pursuit of any course of conduct which is registrable under the
        United Kingdom Restrictive Trade Practices Acts 1976 and 1977 or
        prohibited by or capable of giving rise to an investigation by
        the United Kingdom Director-General of Fair Trading or a
        reference to the United Kingdom Monopolies and Mergers Commission
        or is in material contravention or breach of any of the following
        European Union or United Kingdom Laws and Regulations:  The
        Treaty of Rome 1957;  the Fair Trading Act 1973; the Consumer
        Credit Act 1974; the Health and Safety at Work etc Act 1974;  the
        Trade Descriptions Acts 1968 and 1972; the Restrictive Trade
        Practices Act 1976 and 1977; the Competition Act 1980; the Data
        Protection Act 1984 or any regulations, orders, notices or
        directions made under any of the foregoing.  

                  (l)  U.S. Employee Benefit Plans.  For the purposes of
        this Section 3.2(l), the following definitions shall apply:

                  (i)  Accumulated Funding Deficiency:  An "accumulated
             funding deficiency" as defined in ERISA Section 302(a)(2) or
             the last two sentences of Section 412(a) of the Code, or, in
             either case, successor provisions to such provisions adopted
             by amendments to ERISA or the Code, as the case may be.

                  (ii)  Complete Withdrawal:  A "complete withdrawal"
             from a Multiemployer Plan as defined in Section 4203 of
             ERISA or successor provisions to such provision adopted by
             amendments to ERISA.

                  (iii)  ERISA:  The Employee Retirement Income Security
             Act of 1974, as amended and in effect at the time of
             execution of this Agreement.

                  (iv)  ERISA Affiliate:  ERISA Affiliate shall mean any
             United States member of any controlled group of
             corporations, group of trades or businesses under common
             control, or affiliated service group (as defined for
             purposes of Section 414(b), (c) and (m), respectively, of
             the Code) which includes ATI.

                  (v)  Multiemployer Plan:  A "multiemployer plan" as
             defined in ERISA Section 3(37) or Section 414(f) of the
             Code, or, in either case, successor provisions to such
             provisions adopted by amendments to ERISA or the Code, as
             the case may be.

                  (vi)  Partial Withdrawal:  A "partial withdrawal" from
             a Multiemployer Plan as defined in Section 4205 of ERISA or
             successor provisions to such provision adopted by amendments
             to ERISA.




                                       22
PAGE






                  (vii)  Plan Termination:  A termination, whether
             partial or complete, within the meaning of Title IV of
             ERISA, of a Pension Plan subject to Title IV of ERISA.

                  (viii)  PBGC:  The Pension Benefit Guaranty
             Corporation.

                  (ix)  Pension Plan:  A "pension plan" or "employee
             pension benefit plan" as defined in Section 3(2) of ERISA or
             successor provisions to such provision adopted by amendments
             to ERISA that is applicable to employees of ATI and its
             ERISA Affiliates employed in the U.S.

                  (x)  Prohibited Transaction:  A "prohibited
             transaction" as defined in ERISA Section 406 or Section
             4975(c) of the Code, or, in either case, successor
             provisions to such provisions adopted by amendments to ERISA
             or the Code, as the case may be.

                  (xi)  Reportable Event:  A "reportable event" as
             defined in Section 4043(b) of ERISA or successor provisions
             to such provision adopted by amendments to ERISA.

                  (xii)  Welfare Plan:  A "welfare plan" or an "employee
             welfare benefit plan" as defined in Section 3(1) of ERISA or
             successor provisions to such provision adopted by amendments
             to ERISA that is applicable to employees of ATI employed in
             the U.S.

                  Except as disclosed in the Disclosure Schedule:

                  Neither ATI nor its ERISA Affiliates maintains or
        contributes to any Pension Plan or any Welfare Plan, nor has ATI
        or any of its ERISA Affiliates ever had, an obligation to
        contribute to any Multiemployer Plan.  All Pension Plans and
        Welfare Plans of ATI and its ERISA Affiliates have been
        administered in compliance with their terms, ERISA and, where
        applicable, the Code.  ATI has received from the Internal Revenue
        Service a favorable determination letter with respect to the
        qualification of each such Pension Plan under Section 401(a) of
        the Code and the exemption of any corresponding trust.  A copy of
        each such letter has been furnished to Thermedics.  With respect
        to each Pension Plan:  (A) there is no fact, including, without
        limitation, any Reportable Event, that exists that would
        constitute grounds for termination of such Plan by the PBGC or
        for the appointment by the appropriate United States District
        Court of a trustee to administer such plan, in each case as
        contemplated by ERISA; (B) neither ATI nor any of its ERISA
        Affiliates nor any fiduciary, trustee or administrator of any
        Pension Plan or Welfare Plan has engaged in any Prohibited
        Transaction that could reasonably be expected to subject ATI to
        any material tax or penalty imposed by ERISA or the Code; (C)
        neither ATI nor any of its ERISA Affiliates has any liability to
        the PBGC (other than for payment of premiums); and (D) there is

                                       23
PAGE






        no Accumulated Funding Deficiency with respect to any Pension
        Plan maintained by ATI or any of its ERISA Affiliates, whether or
        not waived.  

                  To ATI's knowledge, (i) no Pension Plan or Welfare
        Plan, ATI or any of its ERISA Affiliates, or any "party in
        interest" or "disqualified person" (as such terms are defined in
        Section 3 of ERISA and Section 4975 of the Code) with respect to
        any Pension Plan or Welfare Plan, has taken any action including
        the making of any investment, or failed to take any action, that
        could reasonably be expected to subject such plan or any Acquired
        Company to any material liability for any tax or for breach of
        fiduciary duty with respect to or in connection with any Pension
        Plan or Welfare Plan; (ii) no Pension Plan or Welfare Plan,
        administrator or fiduciary of any Pension Plan or Welfare Plan,
        or any Acquired Company could reasonably be expected to have any
        material liability under any provision of any applicable law by
        reason of any communication or failure to communicate with
        respect to or in connection with any Pension Plan or Welfare
        Plan, or any filing or failure to file with any governmental
        authority with respect to a Pension Plan or Welfare Plan; and
        (iii) no Pension Plan or Welfare Plan, administrator or fiduciary
        of any Pension Plan or Welfare Plan, or ATI or any of its ERISA
        Affiliates could reasonably be expected to have any material
        liability to any plan participant, beneficiary or other person
        under any provision of any applicable law by reason of any
        payment of benefits or failure to pay benefits, or by reason of
        any credit or failure to give credit for any benefits or rights
        (such as, but not limited to, vesting rights) with respect to
        benefits under or in connection with any Pension Plan or Welfare
        Plan, other than benefit claims in the normal administration of
        each Pension Plan or Welfare Plan.  Neither ATI nor any ERISA
        Affiliate is delinquent or in arrears on any amounts owed to, or
        with respect to any contributions under, any Pension Plan or
        Welfare Plan.  To ATI's knowledge, no person is a participant in
        or eligible for participation (without regard to age or service)
        in, any Pension Plan or Welfare Plan who is not a present or
        former employee of an Acquired Company or a beneficiary of such
        Pension Plan or Welfare Plan.  Except as may be required by the
        Consolidated Omnibus Budget Reconciliation Act of 1985 ("COBRA"),
        none of the Pension Plans or Welfare Plans provides for
        continuing accrual of benefits or coverage for any participant or
        beneficiary of a participant after such participant's termination
        of employment with ATI or any ERISA Affiliate.

                  Except to the extent COBRA requires ATI or any ERISA
        Affiliate to offer health benefits, there are no unfunded
        obligations under any Pension Plan or Welfare Plan providing
        benefits after termination of employment to any employee of ATI
        or its ERISA Affiliates (or beneficiary thereof), including
        without limitation retiree health coverage and deferred
        compensation.  There has been no Plan Termination that has
        occurred during the five-year period ending on the date hereof.
        Neither ATI nor any of its ERISA Affiliates has any liability

                                       24
PAGE






        incurred under Title IV of ERISA with respect to any Pension Plan
        maintained by a trade or business (whether or not incorporated)
        which is under common control with, or part of a controlled group
        of corporations with, ATI, within the meaning of Sections 414(b)
        or (c) of the Code.  To ATI's knowledge, no event has occurred
        and no condition exists with respect to any Pension Plan or
        Welfare Plan that would subject ATI or any ERISA Affiliate to any
        tax under Section 4972, 4977, 4979 or 4980B of the Code or to a
        fine under ERISA Section 502(c) with respect to any such plan.
        No Welfare Plan is funded with a trust or other funding vehicle,
        other than insurance policies.  No Welfare Plan or Pension Plan,
        plan documentation or agreement, summary plan description or
        other written communication distributed to employees prohibits
        ATI or any ERISA Affiliate from amending or terminating any such
        plan.  There has occurred no Complete Withdrawal or Partial
        Withdrawal with respect to any Multiemployer Plan that could
        reasonably be expected to cause ATI or any of its ERISA
        Affiliates to incur any liability under or as a result of ERISA
        other than to the extent previously paid or fully provided for in
        the Pre-Closing Balance Sheet, and all payments required to be
        made to any such Plan by ATI and its ERISA Affiliates under any
        applicable collective bargaining agreements have been made.  As
        of the date of the Pre-Closing Balance Sheet, neither ATI nor any
        ERISA Affiliate had any material liability in connection with any
        Pension Plan, Welfare Plan or other employee benefit plan which
        was not fully provided for on the Pre-Closing Balance Sheet.
        Except as set forth on the Disclosure Schedule, there are no
        actions, arbitrations or claims pending or threatened with
        respect to any Pension Plan, Welfare Plan or other employee
        benefit plans or any fiduciary or sponsor thereof that if
        resolved adversely could reasonably be expected to result in a
        material liability to ATI or its ERISA Affiliates.  

                  (m)  Foreign Employee Benefit Plans.  The Disclosure
        Schedule lists  (i) each retirement plan that is not statutorily
        required (disregarding for this purpose the United Kingdom
        Statutory requirement for any contracted-out schemes to provide
        guaranteed minimum pensions under the United Kingdom Pension
        Schemes Act 1993) that is maintained or contributed to by or on
        behalf of any Acquired Company applicable to employees located
        outside of the U.S. (a "Foreign  Retirement Plan") and (ii) each
        welfare benefit plan that is not required by statute or
        applicable national industry-wide agreement maintained or
        contributed to by or on behalf any Acquired Company applicable to
        employees located outside of the U.S. and which, in the case of
        clause (ii), obligates or may reasonably be expected to obligate
        any Acquired Company to provide a value of more than $50,000
        annually (a "Foreign Welfare Plan").   Each such Foreign
        Retirement Plan and Foreign Welfare Plan (collectively, the
        "Foreign Plans") is fully funded, has been administered in
        compliance with its terms and the requirements of all applicable
        Laws and Regulations (including, without limitation, Article 119
        of the Treaty of Rome), and all required contributions to each
        Foreign Plan have been made.  The books and records of the

                                       25
PAGE






        Acquired Companies accurately reflect the obligations and
        liabilities of the Acquired Companies under the Foreign Plans.
        ATI has heretofore delivered to Thermedics true and complete
        copies of all of the written Foreign Plans and written summaries
        of the oral Foreign Plans and, where applicable, related trusts
        and contracts, including all amendments.  There are no inquiries
        or investigations by any foreign governmental authority, no
        termination proceedings and no actions, suits or claims (other
        than claims for benefits) pending or, to ATI's knowledge,
        threatened against any Foreign Plan (or against any Acquired
        Company with respect thereto) or the assets thereof.  There are
        no unfunded obligations under any Foreign Plan providing benefits
        after termination of employment to any employee or former
        employee of any Acquired Company (or to any beneficiary of any
        such employee or former employee), including but not limited to
        retiree health coverage and deferred compensation, but excluding
        insurance conversion privileges under applicable foreign law.  No
        Foreign Plan, plan documentation or agreement, summary plan
        description or other written communication distributed generally
        to employees of any Acquired Company by its terms prohibits the
        amendment or termination of any such Foreign Plan.  All reports,
        forms and other documents required to be filed or advisable to be
        filed with any governmental authority with respect to each
        Foreign Plan have been timely filed and are complete and accurate
        in all material respects.  

                  (n)  Labor Matters.  To ATI's knowledge, no Acquired
        Company has ever experienced any strike, material grievance,
        material claim of unfair labor practices or other collective
        bargaining dispute. To ATI's knowledge, there is no
        organizational effort presently being made or threatened by or on
        behalf of any labor union with respect to the employees of any
        Acquired Company.  There are not in existence and, to ATI's
        knowledge, there are not threatened any material (i) work
        stoppages or strikes, (ii) grievance, arbitration proceedings or
        proceedings before any industrial tribunal arising out of
        collective bargaining agreements, national labor union agreements
        or otherwise covering the employees of any Acquired Company, or
        (iii) unfair labor practice complaints.  No Acquired Company
        recognizes (expressly or impliedly) any trade union other than as
        identified on the Disclosure Schedule.  No other trade union has
        made any claim for recognition by any Acquired Company.  No
        Acquired Company has made any representations or statements to
        any of its employees in any way connected with or concerning
        employment with the Surviving Corporation or any of its
        affiliates which representation or statement conflicts with, or
        is additional to, the terms of this Agreement.  There are no
        requirements or arrangements (whether or not intended to be
        legally binding) on the part of any Acquired Company to pay any
        employee any sums on redundancy other than under any applicable
        Laws and Regulations.  The Disclosure Schedule contains a
        complete and accurate list of all employees terminated by ATI or
        by any other Acquired Company that is subject to the Worker
        Adjustment and Retaining Notification Act, as amended (the "WARN

                                       26
PAGE






        Act"), in the 90-day period immediately prior to the date of this
        Agreement.

                  (o)  Contracts.  The Disclosure Schedule contains a
        list of the following  contracts, understandings, commitments and
        agreements to which ATI or any of its Subsidiaries is a party
        (whether or not reduced to writing):

                       (i)  all contracts, leases, understandings or
             commitments, whether in the ordinary course of business or
             not: (A) involving a present or future obligation to
             purchase, lease or deliver goods or services of an amount or
             value in excess of $100,000 each; or (B) which limit or
             restrict the ability of any Acquired Company to compete
             anywhere in the world;

                       (ii)  all bonus, incentive or deferred
             compensation arrangements, all profit sharing, pension,
             multiemployer pension, vacation, group insurance or employee
             welfare plans or other similar plans or fringe benefits
             which could result in a cost to any Acquired Company of more
             than $100,000 per annum;

                       (iii)  all collective bargaining agreements or
             other contracts or commitments to or with any labor union,
             employee representative or group of employees, and ATI has
             made available to Thermedics all employment manuals,
             booklets and the like setting forth the terms of employment
             and labor policies and practices (whether or not legally
             binding) that are of general application to its employees;

                       (iv)  each employment contract, and each other
             contract, agreement or commitment to or with an individual
             employee, agent, representative or consultant for a
             remuneration which exceeds or will exceed in accordance with
             its terms $100,000 per annum or which cannot be terminated
             at any time without liability to the employer, upon no more
             than six months notice;

                       (v)  any arrangement under which any Acquired
             Company has created, incurred, assumed or guaranteed
             indebtedness for borrowed money involving more than
             $100,000; 

                       (vi)  each sales representative, distributorship
             or other agreement providing for the distribution or
             marketing of products which is not terminable by the
             Acquired Company upon no more than six months prior notice
             to the other party thereto without breach, penalty, or other
             financial obligation to such other party thereto; 

                       (vii)  any agreement concluded within the past
             five years relating to the acquisition or disposition of
             assets, businesses or companies for a price in excess of

                                       27
PAGE






             $1,000,000 (whether by sale of assets, sale of stock, merger
             or otherwise); and

                       (viii)  any other arrangement under which the
             consequences of a default or termination could have a
             material adverse effect upon the business, assets or
             financial condition of ATI, or which gives or could give any
             other party thereto the right to cause the transactions
             contemplated by this Agreement to be rescinded following
             consummation, or which involves more than $250,000 in the
             aggregate.

             ATI has delivered or made available to Thermedics a correct
        and complete copy of (i) each written arrangement (as amended to
        date) listed in the Disclosure Schedule.  With respect to each
        written arrangement so listed:  (i) to ATI's knowledge, the
        written arrangement is legal, valid, binding and enforceable and
        in full force and effect with respect to each party thereto;
        (ii) each written arrangement to which any Acquired Company is a
        party is assignable by such Acquired Company without the consent
        or approval of or any payment to any party (except as set forth
        in the Disclosure Schedule), and the consummation of the
        transactions contemplated herein will not result in a violation
        or breach of or constitute a default under (or would result in a
        violation, breach or default with the giving of notice or the
        passage of time or both) any such written arrangement which
        violation, breach or default (together with all other such
        violations, breaches or defaults) would have a material adverse
        effect upon the business, assets or financial condition of ATI;
        and (iii) no Acquired Company nor, to ATI's knowledge, any other
        party thereto is in breach or default, and no event has occurred
        which, with notice and/or lapse of time, would constitute such a
        breach or default or permit a termination, modification or
        acceleration, under the written arrangement, which breach or
        default would have a material adverse effect upon the business,
        assets or financial condition of ATI.  No Acquired Company is a
        party to any oral contract, agreement or other arrangement which,
        if reduced to written form, would be required to be listed in the
        Disclosure Schedule under the terms of this subsection (o).  

                  (p)  Insurance Policies.  The Disclosure Schedule sets
        forth a list (including the name of the insurer, the amount of
        total annual premiums, and the type and amount of coverages) of
        all material policies of fire, theft, casualty, liability,
        burglary, fidelity, workers compensation, business interruption,
        environmental, product liability, automobile and other forms of
        insurance under which any Acquired Company is a named insured or
        otherwise the beneficiary of coverage.  No Acquired Company has
        received any notice from the insurer under any such policy
        disclaiming coverage, reserving rights with respect to a
        particular claim or such policy in general, or canceling or
        materially amending any such policy.  All premiums due and
        payable for such insurance policies have been duly paid, and such
        policies or extensions or renewals thereof in the amounts

                                       28
PAGE






        described will be outstanding and duly in full force without
        interruption through the Closing  Date.  

                  (q)  Inventory.  The value of the inventory as stated
        on the Pre-Closing Balance Sheet reflects the lower of cost or
        market for such inventory as applied in accordance with generally
        accepted accounting principles.   All inventory reflected on the
        Pre-Closing Balance Sheet consists of a quality and quantity
        usable and salable in the ordinary course of business, except for
        scrap, excess or obsolete items and items that are of
        below-standard quality or broken before completion of final
        manufacture, all of which have been written-off or written-down
        to net realizable value on the Pre-Closing Balance Sheet.  All
        inventory purchased since the date of the Pre-Closing Balance
        Sheet consists of a quality and quantity usable and salable in
        the ordinary course of business, except for scrap, excess or
        obsolete items and items that are of below-standard quality or
        are broken before completion of final manufacture, all of which
        have been written-off or written-down to net realizable value on
        ATI's books.

                  (r)  Backlog.  The firm sales orders and commitments
        for the Acquired Companies' services and products that make up
        the Acquired Companies' backlog as of the date of the Pre-Closing
        Balance Sheet (the "Backlog") is not less than $7,500,000.  All
        such orders and commitments and any quotations for work which are
        outstanding at that time contain terms and conditions that are
        consistent with the past practice of the Acquired Companies over
        the past year.

                  (s)  No Changes.  Except as expressly contemplated by
        this Agreement or as set forth in the Disclosure Schedule, since
        the date of the Pre-Closing Balance Sheet each Acquired Company
        has conducted its business only in the ordinary course, and none
        of the following has occurred:

                       (i)   any material adverse change in the condition
              (financial or other), results of operations, business,
             assets, liabilities or customer, supplier and employee
             relations or prospects of any Acquired Company; 

                       (ii)  any damage, destruction or loss (whether or
             not covered by insurance) to property which materially and
             adversely affects the condition (financial or other),
             results of operations, business, assets, liabilities, or
             customer, supplier and employee relations, or prospects of
             any Acquired Company;

                       (iii)  any declaration, setting aside or payment
             of any dividend, or other distribution, in respect of the
             capital stock of any Acquired Company or any direct or
             indirect redemption, purchase or other acquisition of such;



                                       29
PAGE






                       (iv)  any option to purchase the capital stock of
             any Acquired Company granted to any person, or any
             employment or deferred compensation agreement entered into
             between any Acquired Company and any of its officers,
             directors or consultants;

                       (v)  any issuance or sale by any Acquired Company,
             or any commitment by any Acquired Company to issue, of any
             stock (other than upon the exercise of stock options), bonds
             or other corporate securities, or any partial or complete
             formation, acquisition, disposition or liquidation of any
             Acquired Company;

                       (vi)  any labor union trouble (including without
             limitation any negotiation, or request for negotiation, with
             respect to any union representation or any labor contract)
             respecting any Acquired Company;

                       (vii)  any statute, rule or regulation, or any
             government policy adopted which pertains particularly to the
             business of any Acquired Company (and not businesses in
             general) and which may materially and adversely affect the
             business or assets of ATI; 

                       (viii)  any change in accounting methods,
             principles or practices by any Acquired Company materially
             affecting its assets, liabilities or business, except
             insofar as may have been required by a change in generally
             accepted accounting principles; 

                       (ix)  any reevaluation by any Acquired Company of
             any of its assets, including, without limitation, writing
             down (or up) the value of inventory or writing off (or
             failing to write off) notes or accounts receivable other
             than in the ordinary course of business consistent with past
             practice, which has resulted in, or reasonably could be
             expected to result in, a material adverse effect upon the
             business, assets or financial condition of ATI; or

                       (x)  any agreement by any Acquired Company to do
             any of the things described in the preceding clauses (i)
             through (ix) other than as expressly contemplated herein.

                  (t)  Liens on Assets.   The assets, including any real
        property in which any Acquired Company has an interest, reflected
        in the Pre-Closing Balance Sheet or acquired in the ordinary
        course of business since the date of the Pre-Closing Balance
        Sheet (the "Assets") (except those Assets sold or disposed of in
        the ordinary course of business for full and fair consideration),
        are free and clear of all mortgages, security interests, pledges,
        liens and encumbrances (collectively, "Encumbrances") other than
        (i) as set forth on the Disclosure Schedule, (ii) as reflected in
        the Pre-Closing Balance Sheet, (iii) Encumbrances on Assets
        which, in the aggregate, are not material to ATI, and (iv) liens

                                       30
PAGE






        for state and local property taxes not in arrears and liens
        arising by operation of law.

                  (u)  Litigation or Proceedings.  No Acquired Company is
        engaged in, or a party to, or, to ATI's knowledge, threatened
        with, any claim or legal action or other proceeding before any
        court, any arbitrator of any kind or any administrative agency,
        or any governmental investigation, or any suspension or debarment
        proceeding, nor, to ATI's knowledge, does any basis for any claim
        or legal action or other proceeding or governmental investigation
        or any suspension or debarment proceeding exist.  There are no
        orders, rulings, decrees, judgments or stipulations to which any
        Acquired Company is a party by or with any court, arbitrator or
        administrative agency affecting ATI, or its business or
        properties.  

                  (v)  Books and Records.  The books, records, accounts,
        ledgers and files of ATI and of each Subsidiary are accurate and
        complete in all material respects and have been maintained in
        accordance with good business and bookkeeping practices in all
        material respects.  The minute books and other similar records of
        ATI and of each Subsidiary of actions taken at any meetings of
        its stockholders, Board of Directors, Managing  Board,
        Supervisory Board or any committee thereof and of all written
        consents executed in lieu of the holding of any such meeting are
        true and complete in all material respects.  The stock
        certificate books, stock ledgers and/or share registers of ATI
        and of each Subsidiary are complete and correct in all material
        respects.  

                  (w)  Government Contracts.  To ATI's knowledge, no
        Acquired Company has ever been suspended or debarred from bidding
        on contracts or subcontracts with any governmental authority; no
        such suspension or debarment has been initiated or, to ATI's
        knowledge, threatened; and the consummation of the transactions
        contemplated by this Agreement will not result in any such
        suspension or debarment).  To ATI's knowledge, no Acquired
        Company has ever been audited or investigated, and it has not
        been threatened with any investigation, by the U.S. Government
        Accounting Office, the U.S. Department of Defense or any of its
        agencies, the Defense Contract Audit Agency, the U.S. Department
        of Justice, the Inspector General of any agency of the U.S.
        government, any similar agencies or instrumentalities of any
        foreign government, or any prime contractor with a governmental
        authority nor, to ATI's knowledge, has any such audit or
        investigation been threatened.  There is no valid basis for (a)
        the suspension or debarment of any Acquired Company from bidding
        on contracts or subcontracts with any governmental authority or
        (b) any claim pursuant to any audit by any governmental authority
        in connection with any contracts or subcontracts relating to the
        provision of products or services to or for the benefit of a
        governmental authority.  No Acquired Company has any agreements,
        contracts or commitments which require it to obtain or maintain a
        security clearance with any governmental authority.

                                       31
PAGE







                  (x)  Recalls.  To ATI's knowledge, there is no basis
        for the recall, withdrawal or suspension of any approval by any
        governmental authority with respect to any product or service
        sold by any Acquired Company.  None of the products or services
        of any Acquired Company is subject to any recall proceedings and
        no such proceedings have been threatened in writing.  To ATI's
        knowledge, no product or service of any Acquired Company has ever
        been recalled.

                  (y)  Antitrust Filings.  ATI has complied, or will
        comply before the Effective Date, with all applicable
        requirements under the Antitrust Improvements Act and the
        Competition Laws relating to filings with and furnishing
        information to the Federal Trade Commission, the United States
        Department of Justice and any other relevant governmental
        authority in connection with the transactions contemplated
        hereby.

                  (z)  Brokers and Finders.  Except for CS First Boston
        Incorporated, ATI has not employed any broker, agent or finder or
        incurred any liability on behalf of ATI for any brokerage fees,
        agents' commissions or finders' fees in connection with the
        transactions contemplated hereby.  ATI has delivered to
        Thermedics a true and correct copy of its agreement with CS First
        Boston Incorporated with respect to the transactions contemplated
        by this Agreement. 

                  (aa) Product Warranties.  Copies of the standard terms
        and conditions of sale with respect to each product line of each
        Acquired Company have been provided by ATI to Thermedics.  No
        Acquired Company has any active warranties in effect in
        connection with the sale of any such products the terms of which
        differ in any material respect from such standard terms and
        conditions.  The reserve established on the Pre-Closing Balance
        Sheet for the satisfaction of claims which may be made under
        product warranties in effect as of the Closing Date are adequate
        in amount to satisfy all product warranty claims which may be
        made with respect to any products sold by any Acquired Company
        prior to the Closing Date.

                  (bb) Statements True and Correct; Further
        Representations and Warranties.  To ATI's knowledge, this
        Agreement (including the Exhibits and any documents delivered
        pursuant hereto) does not contain any untrue statement of a
        material fact or omit any material fact required to be stated
        herein or therein or necessary to make the statements contained
        herein or therein, in the light of the circumstances under which
        they were made, not misleading.

             Section 3.3.  Representations and Warranties of Thermedics.
        Thermedics and Acquisition represent and warrant to ATI that:



                                       32
PAGE






                  (a)  Organization and Qualification.  Thermedics is a
        corporation duly organized, validly existing and in good standing
        under the laws of the Commonwealth of Massachusetts, and has all
        requisite corporate power and authority to own, lease and operate
        its properties and to carry on its business as it is now being
        conducted.  Acquisition is a corporation duly organized, validly
        existing and in good standing under the laws of the State of
        Delaware, and has all requisite corporate power and authority to
        own, lease and operate its properties and to carry on its
        business as it is now being conducted.  

                  (b)  Authority.   The execution and delivery hereof,
        and the consummation of the transactions contemplated hereby,
        have been, or prior to the Effective Date will be, duly and
        validly authorized by all necessary corporate action on the part
        of Thermedics and Acquisition, and, subject to such
        authorization, this Agreement constitutes the valid and legally
        binding obligation of Thermedics and Acquisition enforceable in
        accordance with its terms, except to the extent that such
        enforcement may be subject to applicable bankruptcy, insolvency,
        reorganization, moratorium or other similar laws now or hereafter
        in effect, and except that the remedy of specific performance and
        injunctive and other equitable relief may be subject to equitable
        defenses and to the discretion of the court before which any
        proceeding therefor may be brought.  Neither the execution and
        delivery hereof nor the consummation of the transactions
        contemplated hereby will (i) conflict with or result in a
        violation, breach or termination of or default under (or would
        result in a violation, breach, termination or default with the
        giving of notice or passage of time or both) any of the terms,
        conditions or provisions of the respective Certificate of
        Incorporation or Bylaws of Thermedics or Acquisition, as amended,
        or of any note, bond, mortgage, indenture, license, agreement or
        other instrument or obligation to which Thermedics or Acquisition
        is a party, or by which Thermedics or Acquisition or any of their
        properties or assets may be bound or affected, (ii) result in the
        violation of any order, writ, injunction, decree, statute, rule
        or regulation applicable to Thermedics or Acquisition, or their
        properties or assets or (iii) result in the imposition of any
        lien, encumbrance, charge or claim upon any of the assets of
        Thermedics or Acquisition.  Except for (i) a filing under the
        Antitrust Improvements Act, (ii) filings under the Competition
        Laws, and (iii) filing of the Certificate of Merger with the
        Secretary of State of the State of Delaware, no consent or
        approval by, or notification to or filing with, any court,
        governmental authority or third party or waiting period imposed
        by law is required in connection with the execution, delivery and
        performance of this Agreement by Thermedics or Acquisition or the
        consummation of the transactions contemplated hereby. 

                  (c)  Antitrust Filings.  Thermedics has complied, or
        will comply before the Effective Date, with all applicable
        requirements under the Antitrust Improvements Act and the
        Competition Laws relating to filings with and furnishing

                                       33
PAGE






        information to the Federal Trade Commission, the United States
        Department of Justice and any other relevant governmental
        authority in connection with the transactions contemplated
        hereby.

             Section 3.4.  Representations and Warranties Separate.  In
        the event of any inconsistency or overlap among the
        representations and warranties made herein, the representation
        and warranty most restrictive to the party making the
        representations and warranties shall govern and control.


                                    ARTICLE 4

                                    COVENANTS

             Section 4.1.  Acts of ATI.  ATI agrees that, from the date
        hereof to the Effective Date, except (i) to the extent that
        Thermedics shall otherwise give its written consent or (ii) as
        necessary to consummate the transactions contemplated by this
        Agreement and the Russell Agreement or the THI Agreement:

                  (a)  Business in Ordinary Course.  Each Acquired
        Company will operate its business only in the ordinary course
        consistent with past practice and, to the extent of and
        consistent with such operation, will use its best efforts to
        preserve intact its present business organization and to preserve
        its relationships with employees and persons having business
        dealings with it.

                  (b)  Maintain Properties.  Each Acquired Company will
        maintain all of its properties in customary repair, order and
        condition, reasonable wear and use and damage by unavoidable
        casualty excepted, and take all steps reasonably necessary to
        maintain its Intellectual Property.  

                  (c)  Maintain Management.  No Acquired Company will
        make any changes in the persons serving as management of such
        Acquired Company other than to replace members of management who
        may resign or who may be terminated by such Acquired Company
        prior to the Closing.  In no event will any Acquired Company
        increase the number of persons serving as management of such
        Acquired Company.  

                  (d)  Compensation.  No Acquired Company will (i) grant
        any increase in compensation or bonus to any member of management
        or (ii) enter into or amend or alter any bonus, incentive
        compensation, deferred compensation, profit sharing, stock
        option, retirement, severance, indemnification, pension,
        insurance, death benefit or other fringe benefit plan, agreement
        or arrangement, or any employment or consulting agreement, except
        as may be required to comport with changes in law or in order to
        obtain from the Internal Revenue Service a favorable
        determination letter on the qualified status of any Pension or

                                       34
PAGE






        Welfare Plan.  Copies of any such amended or altered plans or
        agreements shall be delivered by ATI to Thermedics on a timely
        basis.

                  (e)  No Related Party Transactions.  No Acquired
        Company will enter into any transaction or contract with any of
        its shareholders, officers, management, directors or employees or
        their family members, including the lending of any monies.

                  (f)  Indebtedness.  No Acquired Company will create,
        incur, assume, guarantee, or otherwise become liable with respect
        to any indebtedness other than in the ordinary course of
        business.

                  (g)  Maintain Books.  Each Acquired Company will
        maintain its books, accounts and records in its usual, regular
        and ordinary manner. 

                  (h)  No Amendments.  Neither ATI nor any of its
        Subsidiaries will amend its Certificate of Incorporation or
        Bylaws, and each such entity will maintain its corporate
        existence and powers and its qualifications as a foreign
        corporation in each jurisdiction where it is so qualified.

                  (i)  Taxes.  Each Acquired Company will file all tax
        returns and pay all taxes as they become due.  No Acquired
        Company will make any tax election or, except in the ordinary
        course of business consistent with past practice, settle or
        compromise any federal, state, provincial, local or foreign tax
        liability.

                  (j)  No Disposition or Encumbrances.  Each Acquired
        Company will refrain from selling, pledging, disposing of or
        encumbering any of its properties and assets (including, without
        limitation, any indebtedness owed to them or any claims held by
        them) other than in the ordinary course of business.

                  (k)  Insurance.  Each Acquired Company will maintain
        insurance upon its properties and insurance in respect of the
        kinds of risks currently insured against, in accordance with its
        current practice.

                  (l)  No Mergers.  No Acquired Company will merge or
        consolidate with any other corporation, or acquire any stock, or,
        except in the ordinary course of business, any business, property
        or assets of any other person, firm, association, corporation or
        other business organization, nor will any Acquired Company enter
        in to any agreement to do any of the foregoing.

                  (m)  No Securities Issuance.  Other than pursuant to
        the exercise of ATI Options granted prior to the date hereof, no
        Acquired Company will issue any shares of capital stock, or enter
        into any commitment or agreement, or grant any option, warrant or
        right, calling for the issuance of any shares of stock, and no

                                       35
PAGE






        Acquired Company will create or issue any securities convertible
        into any such shares or convertible into securities in turn so
        convertible, or enter into any commitment or agreement, or grant
        any option, warrant or right, calling for the issuance of any
        such convertible securities.

                  (n)  Dividends; Repurchases.  No Acquired Company will
        (i) declare any dividends on or in respect of shares of capital
        stock (other than a dividend declared by a Subsidiary and payable
        only to another Acquired Company); (ii) redeem, repurchase or
        otherwise acquire any shares of its stock or (iii) split, combine
        or reclassify any shares of its stock.

                  (o)  Contracts.  Except in the ordinary course of
        business consistent with its past practice, no Acquired Company
        will enter into, assume or cancel any material contract,
        agreement, obligation, lease, license or commitment, and it will
        not do any act or omit to do any act which would cause a material
        breach of or default under any contract, commitment or obligation
        of any Acquired Company.

                  (p)  Advice of Change.  ATI will promptly advise
        Thermedics in writing of any material adverse change in the
        condition (financial or otherwise), results of operations,
        assets, liabilities, earnings, business or prospects of ATI.

                  (q)  Due Compliance.  Each Acquired Company will duly
        comply in all material respects with all laws, rules and
        regulations applicable to it and to the conduct of its business.

                  (r)  No Waivers of Rights.  No Acquired Company will
        amend, terminate or waive any material right.

                  (s)  Capital Commitments.  No Acquired Company will
        make or commit to make any single capital expenditure, capital
        addition or capital improvement, or series of related capital
        expenditures, including any capital lease, involving an amount in
        excess of $100,000.

                  (t)  No Breaches.  No Acquired Company will take any
        action that would constitute or result in a breach of any
        representation or warranty herein, either as of the date made or
        on the Effective Date.

                  (u)  Confidential Information.  No Acquired Company
        shall, except as required by law or by agreements existing on the
        date hereof, disclose to any third person, and shall preserve and
        maintain and prevent the disclosure or publication of, any
        proprietary information or trade secrets belonging to any
        Acquired Company.

                  (v)  Objections to the Merger.  ATI will promptly
        advise Thermedics of any written objection to the Merger from a
        Shareholder.

                                       36
PAGE







             Section 4.2.  Satisfaction of Conditions Precedent.  The
        parties hereby agree, subject to the terms and conditions
        provided in this Agreement, to use their reasonable efforts to
        take, or cause to be taken, all action, and to do, or cause to be
        done, all things necessary, appropriate or desirable under
        applicable laws and regulations to consummate the transactions
        contemplated by this Agreement, including the satisfaction of the
        conditions precedent contained in Article 5 hereof.  Each party
        will use their respective reasonable efforts to obtain consents
        of all third-parties and governmental authorities necessary,
        appropriate or desirable for the consummation of the transactions
        contemplated by this Agreement.  

             Section 4.3.  Shareholders' Approval.  ATI shall take all
        action necessary in accordance with applicable law to convene a
        Shareholder meeting at the earliest possible time after the date
        hereof for the purpose of approving and adopting this Agreement
        (including the transactions contemplated hereby).  Subject only
        to the exercise of its fiduciary duty upon advice of counsel,
        ATI's Board of Directors shall recommend to the Shareholders the
        adoption of this Agreement and the approval of the Merger.  ATI
        shall use all reasonable efforts to obtain all votes and
        approvals of the Shareholders necessary for the approval and
        adoption of this Agreement and the transactions contemplated
        hereby under the General Corporation Law and its Certificate of
        Incorporation and Bylaws.

             Section 4.4.  Certain Employee Benefits Matters.  

                  (a)  Thermedics expressly reserves the right, at no
        cost to the Shareholders and subject to the terms of any Pension
        Plan, Welfare Plan or other benefit plan or program of any
        Acquired Company, to modify or terminate, or to cause to be
        modified or terminated, any such Pension Plan, Welfare Plan or
        other benefit plan or program at any time or from time to time
        after the Closing. 

                  (b)  Except as may be otherwise required by ERISA,
        Thermedics will give employees of the Acquired Companies credit
        for service with such Acquired Companies with respect to any of
        Thermedics' benefit plans which have vesting or length of service
        requirements.

                  (c)  All otherwise eligible employees of the Acquired
        Companies will be entitled to participate in any employee stock
        purchase plan adopted from time to time by Thermedics, in
        accordance with the terms thereof.

                  (d)  The parties hereto do not intend to create any
        third-party beneficiary rights respecting any employee as a
        result of the provisions herein and specifically hereby deny any
        such intention.   


                                       37
PAGE






             Section 4.5.  Expenses.  Each party will bear entirely the
        respective out-of-pocket expenses that it incurs in connection
        with the transactions contemplated hereby including legal and
        accounting fees, provided that, as contemplated by Section 1.6(a)
        hereof, all fees and expenses incurred by ATI to Sonnenschein
        Nath & Rosenthal and to CS First Boston Incorporated or its
        affiliates in connection with the consummation of the
        transactions contemplated hereby shall be deducted from, and paid
        out of, the Purchase Price and shall not be borne by ATI.
        Notwithstanding the foregoing, this Section 4.5 shall not be
        construed as relieving any party from any liability which it may
        have for any breach of any representation or warranty made by it
        herein or any failure to perform any obligation or comply with
        any covenant imposed on it herein.

             Section 4.6.  WARN Act.  During the period commencing on the
        Closing Date and ending ninety days after the Closing Date,
        Thermedics shall not permit ATI or any other Acquired Company
        which is subject to the WARN Act to take any action that
        independently or in connection with any action of ATI or any such
        Acquired Company prior to the Closing Date could be construed as
        a "plant closing" or "mass layoff" within the meaning of the WARN
        Act or the regulations enacted thereunder.  If Thermedics permits
        ATI or any such other Acquired Company to take any such action
        during such 90-day period, Thermedics shall be solely responsible
        for providing any notice required by the WARN Act and for making
        payments, if any, which may be required under the WARN Act and
        for any other liabilities related to its failure to provide
        appropriate notice.

             Section 4.7.  Indemnification of the Shareholders by
        Thermedics.  

                  (a)  The Shareholders upon demand shall be indemnified
        by Thermedics for the full amount of all Damages (as defined
        below) suffered any of them as a direct or indirect result of:

                       (i)  the inaccuracy of any representation or
             warranty made by Thermedics or Acquisition in or pursuant to
             this Agreement (including without limitation Section 3.3);
             and

                       (ii)  any failure by Thermedics or Acquisition to
             perform any obligation or comply with any covenant or
             agreement specified herein (including without limitation the
             covenants set forth in this Article IV) or in any other
             document executed at the Closing.

                  (b)  For the purpose of this Section 4.7, the term
        "Damages" shall be determined and computed by reference to the
        effect of the compensable event on the party or parties entitled
        thereto, and shall be deemed to include all out-of-pocket losses,
        liabilities, expenses or costs incurred by such party or parties,
        including reasonable attorney's fees.

                                       38
PAGE







                  (c)  The right of the Shareholders to be indemnified
        pursuant to this Section 4.7 (i) shall not apply until the sum of
        the Damages suffered by the Shareholders on a cumulative basis
        equals or exceeds $750,000 (the "Threshold"), at which point
        Thermedics shall become liable for all Damages in excess of
        $187,500 (and not just amounts in excess of the Threshold), and
        (ii) shall apply only to claims that are asserted by the
        Shareholders before the 343rd consecutive day after the Closing
        Date (the "Escrow Termination Date").  Individual claims
        involving Damages of less than $10,000 shall not be indemnified
        and shall not be applied in determining whether the aggregate
        Damages exceed the Threshold; provided, however, that a series of
        related claims or claims based on similar facts and circumstances
        shall for purposes of the preceding clause be deemed to be a
        single claim and the Damages claimed with respect to each of such
        claims shall be aggregated in determining whether they exceed
        $10,000.  Thermedics' aggregate liability for claims that are
        asserted by the Shareholders before the Escrow Termination Date
        shall in no event exceed $5,000,000.  Thermedics' liability for
        claims that are asserted by the Shareholders on or after April 1,
        1996 but before the Escrow Termination Date shall in no event
        exceed the difference between (i) $3,000,000 less (ii) the
        aggregate dollar value of any claims asserted by the Shareholders
        hereunder prior to April 1, 1996.  Notwithstanding the foregoing,
        any liability of Thermedics hereunder to the Shareholders shall
        be reduced by any amounts to which the Shareholders may be
        entitled under the indemnification provisions of the THI
        Agreement.  Notwithstanding any provision herein to the contrary,
        the limitations set forth in this Section 4.7(c) shall not apply
        to claims by Shareholders in which it is determined that
        Thermedics has failed to pay the Shareholders all or any portion
        of the Purchase Price in accordance with the terms of this
        Agreement.

                  (d)  The Shareholders shall give Thermedics prompt
        notice of any claim, action or proceeding by a third party which
        is reasonably likely to result in a claim for indemnification
        under this Section 4.7.  Thermedics shall have the right, at its
        expense, to defend, contest, protest, settle and otherwise
        control the resolution of any such claim, action or proceeding.
        Thermedics shall keep the Shareholders apprised of developments
        with respect to any such claim, action or proceeding, and the
        Shareholders shall have the right to consult with Thermedics, and
        to participate therein, subject to Thermedics' right of control
        thereof, at their expense and with counsel selected by them.  If
        Thermedics shall notify the Shareholders that it has elected to
        assume any such defense, contest or protest, Thermedics shall not
        be liable to the Shareholders hereunder for any legal or other
        expense subsequently incurred by them pursuant to the exercise of
        their rights set forth in the preceding sentence.




                                       39
PAGE






                                    ARTICLE 5

                            CONDITIONS TO OBLIGATIONS

             Section 5.1.  Conditions to Obligations of Thermedics and
        Acquisition.  The obligations of Thermedics and Acquisition to
        consummate the transactions contemplated hereby are subject to
        the satisfaction, on or before the Closing, of the following
        conditions (unless waived in writing by Thermedics and
        Acquisition in the manner provided in Section 6.2 hereof):

                  (a)  Representations, Warranties and Performance of
        ATI.  The representations and warranties set forth in Section 3.2
        hereof shall be accurate on and as of the date hereof, and on and
        as of the Closing Date as though made on and as of the Closing
        Date (except to the extent necessary to reflect the consummation
        of the transactions contemplated by the Russell Agreement or by
        the THI Agreement), and ATI shall have performed all obligations
        and complied with all covenants required to be performed or to be
        complied with by it under this Agreement prior to the Closing.
        ATI shall be permitted to deliver a revised Disclosure Schedule
        to Thermedics at any time prior to the Closing, provided,
        however, that Thermedics shall be afforded not less than five
        business days prior to the Closing to review any such revised
        Disclosure Schedule and provided, further, that Thermedics shall
        be entitled to terminate this Agreement and its obligations
        hereunder pursuant to Section 6.3 hereof in the event that any
        such additional or revised disclosure has or could have, in the
        sole judgment of Thermedics, an adverse effect on the financial
        condition, assets, liabilities, earnings, business or prospects
        of ATI.

                  (b)  Authorization.  All action necessary to authorize
        the execution, delivery and performance hereof by ATI and the
        consummation of the transactions contemplated hereby, including
        the approval by the Shareholders of the execution, delivery and
        performance of this Agreement and the Merger in accordance with
        the General Corporation Law shall have been duly and validly
        taken by ATI.  ATI shall have furnished Thermedics with a copy of
        all resolutions adopted by its Board of Directors and
        Shareholders in connection with such actions, certified by the
        Secretary or an Assistant Secretary of ATI, together with copies
        of such other instruments and documents as Thermedics shall have
        reasonably requested.  

                  (c)  Escrow Agreement.  ATI shall have executed and
        delivered the Escrow Agreement.  

                  (d)  Russell and THI Transactions.  Unicam Technology
        Limited and Thermedics shall have executed the Russell Agreement,
        ATI and THI shall have executed THI Agreement, and all conditions
        to precedent to the consummation of the transactions contemplated
        by such agreements shall have been satisfied or waived.


                                       40
PAGE






                  (e)  Consents.  Any governmental authority having
        jurisdiction over any Acquired Company, Thermedics or Acquisition
        or any other person in any contractual or other relationship with
        any Acquired Company, to the extent that its consent or approval
        is required by applicable law or regulation or any applicable
        contract or other instrument for the performance of this
        Agreement or the consummation of the transactions contemplated
        hereby or for the continuation of any existing contractual
        relationship with any Acquired Company, shall have granted any
        necessary consent or approval.

                  (f)  Termination of the Employment Agreements.  ATI
        shall have terminated the Employment Agreements and ATI shall
        have no obligations or liabilities, contingent or otherwise, to
        any of the parties to such Employment Agreements, or to any other
        person or entity, under, on account of, or with respect either
        such Employment Agreements or the terminations thereof.

                  (g)  Dissolution of Certain Subsidiaries.  ATI shall
        have commenced the liquidation and dissolution of Mattson
        Instruments, PTY Ltd. and Unicam AG; and ATI shall have delivered
        to Thermedics evidence of the commencement of such liquidations
        and dissolutions as shall be reasonably satisfactory to
        Thermedics, together with such evidence of the completed
        liquidations and dissolutions of Cryolect Scientific, Orion
        Research AG, and Mattson Instruments GmbH.

                  (h)  Backlog.  The Acquired Companies' Backlog as of
        the Closing Date shall be not less than $7,500,000.

                  (i)  Resignations.  Thermedics shall have received the
        resignations of each of the directors and officers of ATI and its
        Subsidiaries whose resignation has been requested by Thermedics
        prior to the Closing Date.

                  (j)  Severance Agreements.  Each of Messrs. William J.
        Kennedy, Chane Graziano and Robert Kinney shall have executed and
        delivered to ATI Severance Agreements in the form of Exhibit E
        hereto.

                  (k)  Cambridge, England Property.  [Reserved]

                  (l)  Permits and Approvals.  Any and all consents,
        permits, approvals or other actions of any person, jurisdiction
        or authority required in the reasonable opinion of Thermedics
        (including without limitation, confirmation of filing of the
        Certificate of Merger with the Secretary of State of the State of
        Delaware) for lawful consummation of the transactions
        contemplated hereby shall have been obtained, and shall be in
        full force and effect, and no such consent, permit, approval or
        other action shall contain any provision that in the reasonable
        judgment of Thermedics is unduly burdensome.



                                       41
PAGE






                  (m)  Good Standing Certificates.  ATI and each
        Subsidiary shall have delivered to Thermedics a long-form
        corporate good standing certificate from its jurisdiction of
        incorporation (or equivalent evidence of each such Subsidiary's
        status in the case of certain foreign jurisdictions) and good
        standing certificates from each jurisdiction in which ATI or such
        Subsidiary is qualified to transact business (or equivalent
        evidence of each such Subsidiary's status, if such evidence is
        generally available, in the case of certain foreign
        jurisdictions).

                  (n)  Officer's Certificate.  ATI shall have delivered
        to Thermedics a certificate executed by an officer of ATI, dated
        the Effective Date, certifying to the fulfillment of the
        conditions specified in Section 5.1(a).

                  (o)  Dissenters' Rights.  The holders of not more than
        1.5% of the ATI Shares shall have demanded and perfected their
        right to an appraisal of their ATI Shares in accordance with the
        General Corporation Law.

                  (p)  Legal Opinion of Counsel for ATI.  Thermedics
        shall have received an opinion of Sonnenschein Nath & Rosenthal,
        counsel for ATI, dated the Closing Date and in the form attached
        hereto as Exhibit F, together with such other opinions of counsel
        to the Subsidiaries as Thermedics may reasonably require.

                  (q)  No Litigation or Proceedings with Respect to the
        Merger.   No legal action or other proceedings to restrain or
        prohibit the consummation of the transactions contemplated by
        this Agreement shall be pending or threatened.  

                  (r)  Documents Satisfactory.  The form and substance of
        all legal matters contemplated herein and of all papers used or
        delivered hereunder shall be reasonably acceptable to Thermedics,
        and Thermedics shall have received all documents that it may have
        reasonably requested in connection with the transactions
        contemplated hereby, in form and substance reasonably
        satisfactory to it.

                  (s)  Compliance with Competition Laws.  All
        authorizations, approvals, consents, permits or waivers required
        under any Competition Laws shall have been obtained.  

                  (t)  Matters Related to Certain Indebtedness.  ATI
        shall have delivered to Thermedics the following:

                       (i)  a duly executed copy of a payoff letter from
             Bank of America Illinois (f/k/a Continental Bank N.A.), as
             agent, with respect to that certain Credit Agreement dated
             as of May 20, 1993; 

                       (ii)  a duly executed copy of a payoff letter from
             State Street Bank & Trust Company, as Trustee, with respect

                                       42
PAGE






             to the Massachusetts Industrial Finance Agency $1,000,000
             Floating Rate Industrial Revenue Bond - 1985 Series; and

                       (iii)  all documents, including, without
             limitation, executed UCC-3 termination statements, as are
             necessary to release all liens on the assets of ATI and/or
             any of its Subsidiaries which secure the indebtedness
             described in clauses (i) and (ii) above.

                  (u)  Orion Research Limited.  ATI shall have became the
        sole legal and beneficial owner of 100% of the outstanding shares
        of capital stock of Orion Research Limited.

             Section 5.2.  Conditions to Obligations of ATI.  The
        obligations of ATI to consummate the transactions contemplated
        hereby are subject to the satisfaction, on or before the Closing,
        of the following conditions (unless waived by ATI in writing in
        the manner provided in Section 6.2 hereof):

                  (a)  Representations, Warranties and Performance of
        Thermedics and Acquisition.  The representations and warranties
        of Thermedics and Acquisition set forth in Section 3.3 hereof
        shall be accurate on and as of the date hereof, and on and as of
        the Closing Date as though made on and as of the Closing Date,
        and Thermedics and Acquisition shall have performed all
        obligations and complied with all covenants required to be
        performed or to be complied with by them under this Agreement
        prior to the Closing.

                  (b)  Authorization.  All action necessary to authorize
        the execution, delivery and performance hereof by Thermedics and
        Acquisition and the consummation of the transactions contemplated
        hereby shall have been duly and validly taken by Thermedics and
        Acquisition.  Thermedics and Acquisition shall have furnished ATI
        with a copy of all resolutions adopted by the Board of Directors
        of Thermedics and Acquisition and the shareholders of Acquisition
        (if any) in connection with such actions, certified by the
        Secretary or an Assistant Secretary of Thermedics and
        Acquisition, respectively, together with copies of such other
        instruments and documents as ATI shall have reasonably requested.

                  (c)  Consents.  Any governmental authority having
        jurisdiction over ATI, to the extent that its consent or approval
        is required by applicable law or regulation for the performance
        of this Agreement or the consummation of the transactions
        contemplated hereby, shall have granted any necessary consent or
        approval.

                  (d)  Permits and Approvals.  Any and all consents,
        permits, approvals or other actions of any person, jurisdiction
        or authority required in the reasonable opinion of counsel for
        ATI (including without limitation, confirmation of filing of the
        Certificate of Merger with the Secretary of State of the State of
        Delaware) for lawful consummation of the transactions

                                       43
PAGE






        contemplated hereby shall have been obtained, and shall be in
        full force and effect, and no such consent, permit, approval or
        other action shall contain any provision that in the reasonable
        judgment of such counsel is unduly burdensome.

                  (e)  ATI Shareholder Approval.  The approval by the
        Shareholders of the execution, delivery and performance of this
        Agreement and the Merger in accordance with the General
        Corporation Law shall have been duly and validly obtained.

                  (f)  Good Standing Certificates.  Each of Thermedics
        and Acquisition shall have delivered to ATI a corporate good
        standing certificate from its jurisdiction of incorporation.

                  (g)  Officer's Certificate.  Thermedics shall have
        delivered to ATI a certificate executed by an officer of
        Thermedics, dated the Effective Date, certifying to the
        fulfillment of the conditions specified in Section 5.2(a).

                  (h)  No Litigation or Proceedings with Respect to the
        Merger.  No legal action or other proceedings to restrain or
        prohibit the consummation of the transactions contemplated by
        this Agreement shall be pending or threatened.

                  (i)  Documents Satisfactory.  The form and substance of
        all legal matters contemplated herein and of all papers used or
        delivered hereunder shall be reasonably acceptable to counsel for
        ATI and ATI shall have received all documents that such counsel
        may have reasonably requested in connection with the transactions
        contemplated hereby, in form and substance reasonably
        satisfactory to such counsel.

                  (j)  Legal Opinion of Thermedics' Counsel.  ATI shall
        have received an opinion of Thermedics' general counsel, dated
        the Closing Date and in the form attached hereto as Exhibit G.

                  (k)  Compliance with Competition Laws.  All
        authorizations, approvals, consents, permits or waivers required
        under any Competition Laws shall have been obtained.


                                    ARTICLE 6

                      MODIFICATION, WAIVER AND TERMINATION

             Section 6.1.  Modifications and Amendments.  The parties may
        mutually amend any provision of this Agreement at any time prior
        to the Effective Date; provided, however, that any amendment
        effected subsequent to the approval of this Agreement by the
        Shareholders shall be subject to the restrictions contained in
        the General Corporation Law.  No amendment of any provision of
        this Agreement shall be valid unless the same shall be in writing
        and signed by all of the parties.


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PAGE






             Section 6.2.  Waivers.  The parties hereto may, by a written
        signed instrument, extend the time for or waive the performance
        of any of the obligations of another party hereto or waive
        compliance by such other party with any of the covenants or
        conditions contained herein.

             Section 6.3.  Termination.  At any time prior to the
        Closing, this Agreement may be terminated (a) by mutual consent
        of Thermedics and Acquisition, on the one hand, and ATI on the
        other; (b) by Thermedics and Acquisition if (i) there has been a
        material breach by ATI of a covenant, representation or warranty
        contained in this Agreement; (ii) Thermedics has notified ATI in
        writing of the existence of such breach; and (iii) the party in
        breach has failed to cure such breach within a reasonable period
        of time after receiving such notice; (c) by ATI if (i) there has
        been a material breach by Thermedics or Acquisition of a
        covenant, representation or warranty contained in this Agreement;
        (ii) ATI has notified Thermedics in writing of the existence of
        such breach; and (iii) Thermedics or Acquisition, as the case may
        be, has failed to cure such breach within 30 days after receiving
        such notice; (d) by ATI, Thermedics or Acquisition if (i) there
        shall be an order of a court in effect preventing consummation of
        the Merger or (ii) there shall be any action taken, or any
        statute, rule, regulation or order enacted, promulgated, issued
        or deemed applicable to this Agreement, by a governmental
        authority that would make consummation of the Merger illegal; (e)
        by ATI, Thermedics or Acquisition if the Closing does not occur
        by November 30, 1995; or (f) by Thermedics or Acquisition if (i)
        ATI shall have elected to revise the Disclosure Schedule pursuant
        to Section 5.1(a) hereof and (ii) in the sole judgment of
        Thermedics, any such additional or revised disclosure has or
        could have an adverse effect on the financial condition, assets,
        liabilities, earnings, business or prospects of ATI.

             Section 6.4.  Effect of Termination.  If this Agreement
        shall be terminated as provided in Section 6.3, this Agreement
        shall forthwith become void (except as otherwise provided in
        Section 4.5); provided, however, that the foregoing shall not
        relieve any party from liability for damages actually incurred as
        a result of any breach of this Agreement.


                                    ARTICLE 7

                                     GENERAL

             Section 7.1.  Notices.  All notices, requests, demands,
        consents and other communications which are required or permitted
        hereunder shall be in writing, and shall be deemed given when
        actually received or if earlier, one day after deposit with a
        nationally recognized air courier or express mail, charges
        prepaid or three days after deposit in the U.S. mail by certified
        mail, return receipt requested, postage prepaid, addressed as
        follows:

                                       45
PAGE







             If to Thermedics or Acquisition:

                  Thermedics Inc.
                  470 Wildwood Street
                  P. O. Box 2999
                  Woburn, Massachusetts  01888-1799
                  Attention:  President

             With a copy to:

                  Thermo Electron Corporation
                  81 Wyman Street
                  Waltham, Massachusetts  02254
                  Attention:  General Counsel

             If to ATI, to:

                  Analytical Technology, Inc.
                  The Schrafft Center
                  529 Main Street
                  Boston, Massachusetts  02129
                  Attention:  President

             With copies to:

                  Sonnenschein Nath & Rosenthal
                  Suite 8000 Sears Tower
                  233 South Wacker Drive
                  Chicago, IL  60606
                  Attention:  J. Ross Docksey, Esquire

             and to: 

                  Thermo Electron Corporation
                  81 Wyman Street
                  Waltham, Massachusetts  02254
                  Attention:  General Counsel


        or to such other address as any party hereto may designate in
        writing to the other parties, specifying a change of address for
        the purpose of this Agreement.

             Section 7.2.  Entire Agreement.  This Agreement supersedes
        any and all oral or written agreements or understandings
        heretofore made relating to the subject matter hereof (including
        without limitation the Letter of Intent executed by Thermedics'
        parent company, Thermo Electron Corporation, and ATI dated July
        19, 1995) and constitutes the entire agreement of the parties
        relating to the subject matter hereof.

             Section 7.3.  Parties in Interest.  All covenants and
        agreements, representations and warranties contained in this

                                       46
PAGE






        Agreement made by or on behalf of any of the parties hereto shall
        bind and inure to the benefit of the parties hereto, and their
        respective successors, assigns, heirs, executors, administrators
        and personal representatives, whether so expressed or not.

             Section 7.4.  THI Rights; No Other Implied Rights or
        Remedies.  

                  (a)  THI shall be a party to this Agreement solely for
        the purpose of relying on the representations and warranties of
        ATI set forth in this Agreement, including without limitation the
        representations and warranties set forth in Section 3.2 hereof,
        to the same degree that Thermedics is entitled to rely on such
        representations and warranties.  Accordingly, the parties
        acknowledge that THI may seek damages for any such
        misrepresentation to the same degree that Thermedics would be
        entitled to do so; provided, however, that, subject to the terms
        of the Escrow Agreement, THI may enforce its rights and seek such
        damages independently and without the prior approval or
        cooperation of Thermedics.

                  (b)  Except as set forth in the preceding paragraph or
        as otherwise expressly provided herein, nothing herein expressed
        or implied is intended or shall be construed to confer upon or to
        give any person, firm or corporation, other than the parties
        hereto, any rights or remedies under or by reason of this
        Agreement.

             Section 7.5.  Headings.  The headings in this Agreement are
        inserted for convenience of reference only and shall not be a
        part of or control or affect the meaning hereof.

             Section 7.6.  Severability.  If any provision of this
        Agreement shall be declared void or unenforceable by any judicial
        or administrative authority, the validity of any other provision
        shall not be affected thereby.

             Section 7.7.  Counterparts.  This Agreement may be executed
        in two or more counterparts, each of which shall be deemed an
        original, but all of which together shall constitute one and the
        same instrument.

             Section 7.8.  Exhibits.  The Exhibits attached hereto and
        referred to in this Agreement are a part of this Agreement for
        all purposes.

             Section 7.9.  Assignment.  This Agreement and the rights and
        duties hereunder shall be binding upon and inure to the benefit
        of the successors, assigns, heirs and legal and personal
        representatives of the parties hereto, but shall not be
        assignable or delegable by any party without the prior written
        consent of the other parties and any purported assignment without
        such prior written consent shall be null and void, except that


                                       47
PAGE






        Thermedics and Acquisition may assign this Agreement, or rights
        and duties hereunder, after the Closing Date.

             Section 7.10.  Further Assurances.  ATI will execute and
        furnish to Thermedics and Acquisition all documents and will do
        or cause to be done all other things that Thermedics or
        Acquisition may reasonably request from time to time in order to
        give full effect to this Agreement and to effectuate the intent
        of the parties.

             Section 7.11.  Gender.  In this Agreement, unless the
        context requires otherwise the singular includes the plural, the
        plural the singular, the masculine gender includes the neuter,
        masculine and feminine genders and vice versa.

             Section 7.12.  Public Announcement.  The content and timing
        of any public announcement pertaining to this Agreement shall be
        subject to the prior agreement and approval of Thermedics and
        ATI.

             Section 7.13.  Governing Law.  This Agreement shall be
        governed by the law of the State of Delaware applicable to
        agreements made and to be performed wholly within such
        jurisdiction, without regard to the conflicts of laws provisions
        thereof.    

             IN WITNESS WHEREOF, the parties have caused this Agreement
        to be duly executed as of the date first written above.


                                      Thermedics Inc.

        [Seal]                        By: /s/ John W. Wood, Jr.

                                      Title: President



                                      ATI MERGER CORP.

        [Seal]                        By: /s/ John W. Wood, Jr.

                                      Title: President



                                      ANALYTICAL TECHNOLOGY, INC.

        [Seal]                        By: /s/ William J. Kennedy

                                      Title: Chairman and Chief Executive
                                             Officer



                                       48
PAGE









                                      Pursuant to Section 7.4(a):


                                      THERMO INSTRUMENT SYSTEMS INC.

        [Seal]                        By: /s/ Jonathan W. Painter

                                      Title: Treasurer




        AA953400063







































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