SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   SCHEDULE TO

                                 (Rule 14d-100)

            TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                           METRIKA SYSTEMS CORPORATION
                            (Name of Subject Company)

                              METRIKA ACQUISITION INC.
                                    (Offeror)

                         THERMO INSTRUMENT SYSTEMS INC.
                                    (Offeror)

                           THERMO ELECTRON CORPORATION
                                    (Offeror)

                     COMMON STOCK, PAR VALUE $0.01 PER SHARE
                         (Title of Class of Securities)

                                 CUSIP 59159M 10 6
                      (CUSIP Number of Class of Securities)

                             Seth H. Hoogasian, Esq.
                                 General Counsel
                           Thermo Electron Corporation
                                 81 Wyman Street
                        Waltham, Massachusetts 02454-9046
                                 (781) 622-1000
   (Name, Address and Telephone Number of Person Authorized to Receive Notices
                 and Communications on Behalf of Filing Persons)

                                 with a copy to:

                              Neil H. Aronson, Esq.
               Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
                              One Financial Center
                           Boston, Massachusetts 02111
                                 (617) 542-6000





                            CALCULATION OF FILING FEE

Transaction Valuation(1): $18,837,684     Amount of Filing Fee(2): $3,768

(1)   For purposes of calculating fee only. This amount is based upon (a) the
maximum number of Shares to be purchased pursuant to the Offer and (b) the price
offered per Share.

(2)   The amount of the filing fee, calculated in accordance with Regulation
240.0-11 under the Securities Exchange Act of 1934, as amended, equals 1/50 of
one percent of the Transaction Valuation.

[ ]   Check the box if any part of the fee is offset as provided by Rule
      0-11(a)(2) and identify the filing with which the offsetting fee was
      previously paid. Identify the previous filing by registration
      statement number, or the Form or Schedule and the date of its filing.

           Amount Previously Paid:                               Not applicable
           Form or Registration No.:                             Not applicable
           Filing Party:                                         Not applicable
           Date Filed:                                           Not applicable

[ ]   Check the box if the filing relates solely to preliminary
      communications made before the commencement of a tender offer.

      Check the appropriate boxes below to designate any transactions to
      which the statement relates:

      [X]        third-party tender offer subject to Rule 14d-1.

      [ ]        issuer tender offer subject to Rule 13e-4.

      [X]        going-private transaction subject to Rule 13e-3.

      [X]        amendment to Schedule 13D under Rule 13d-2.

      Check the following box if the filing is a final amendment reporting
      the results of the tender offer: [ ]


                          SCHEDULE 13D INFORMATION
- -------------------------------------------------------------------------------
1.  NAMES OF REPORTING PERSONS
    I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

    Thermo Electron Corporation
    IRS No. 04-2209186
- -------------------------------------------------------------------------------
2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*         (a) [ ]
                                                              (b) [x]
- -------------------------------------------------------------------------------
3.  SEC USE ONLY
- -------------------------------------------------------------------------------
4.  SOURCE OF FUNDS*

    WC
- -------------------------------------------------------------------------------





5.  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
    REQUIRED PURSUANT TO ITEM 2 (d) OR 2 (e)                      [ ]
- -------------------------------------------------------------------------------
6.  CITIZENSHIP OR PLACE OF ORGANIZATION

    State of Delaware
- -------------------------------------------------------------------------------
NUMBER OF                                    7.  SOLE VOTING POWER
SHARES
BENEFICIALLY                                     5,846,700
OWNED BY                                  ------------------------------------
EACH
REPORTING                                    8.  SHARED VOTING POWER
PERSON WITH
                                                 0
                                          ------------------------------------
                                             9.  SOLE DISPOSITIVE POWER

                                                 5,846,700
                                          ------------------------------------
                                            10.  SHARED DISPOSITIVE POWER

                                                 0
- -------------------------------------------------------------------------------
11.     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

        5,846,700
- -------------------------------------------------------------------------------
12.     CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
        CERTAIN SHARES*                                                  [ ]
- -------------------------------------------------------------------------------
13.     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

        78.9%
- -------------------------------------------------------------------------------
14.     TYPE OF REPORTING PERSON*

        CO
- -------------------------------------------------------------------------------

This Tender Offer Statement on Schedule TO relates to the offer by Metrika
Acquisition Inc., a Delaware corporation (the "Purchaser") and a wholly-owned
subsidiary of Thermo Instrument Systems Inc., a Delaware corporation ("Thermo
Instrument"), to purchase all outstanding shares of common stock, par value
$0.01 per share (the "Shares"), of Metrika Systems Corporation, a Delaware
corporation (the "Company"), at a purchase price of $9.00 per Share net to
the seller in cash, without interest thereon, upon the terms and subject to
the conditions set forth in the Offer to Purchase dated March 31, 2000 (the
"Offer to Purchase"), a copy of which is attached hereto as Exhibit 12(a)(1),
and in the related Letter of Transmittal (which, together with the Offer to
Purchase, constitute the "Offer"), a copy of which is attached hereto as



Exhibit 12(a)(2). The information in the Offer to Purchase under the
captions "Summary", "Introduction", "The Company", "Special Factors", "The
Tender Offer", "Certain Federal Income Tax Consequences", "Price Range Of The
Shares; Dividends", "Certain Information Concerning The Company", "Certain
Information Concerning The Purchaser, Thermo Instrument And Thermo Electron",
"Source And Amount Of Funds", "The Merger; Appraisal Rights", "Fees And
Expenses" and "Miscellaneous" and Schedules I, II and III to the Offer to
Purchase are incorporated herein by reference as set forth below.

ITEM 1.   SUMMARY TERM SHEET.

See the section of the Offer to Purchase captioned "Summary".

ITEM 2.   SUBJECT COMPANY INFORMATION.

          (a) See the section of the Offer to Purchase captioned "Certain
          Information Concerning The Company".

          (b) See the section of the Offer to Purchase captioned "Introduction".

          (c) See the section of the Offer to Purchase captioned "Price Range Of
          The Shares; Dividends".

ITEM 3.   IDENTITY AND BACKGROUND OF FILING PERSON.

          (a) See the section of the Offer to Purchase captioned "Certain
          Information Concerning The Purchaser, Thermo Instrument And Thermo
          Electron" and Schedule I to the Offer to Purchase ("Members Of The
          Boards Of Directors And Executive Officers Of The Purchaser, Thermo
          Instrument And Thermo Electron").

          (b) See the section of the Offer to Purchase captioned "Certain
          Information Concerning The Purchaser, Thermo Instrument And Thermo
          Electron" and Schedule I to the Offer to Purchase ("Members Of The
          Boards Of Directors And Executive Officers Of The Purchaser, Thermo
          Instrument And Thermo Electron").

          (c) See the section of the Offer to Purchase captioned "Certain
          Information Concerning The Purchaser, Thermo Instrument And Thermo
          Electron" and Schedule I to the Offer to Purchase ("Members Of The
          Boards Of Directors And Executive Officers Of The Purchaser, Thermo
          Instrument And Thermo Electron").

ITEM 4.   TERMS OF THE TRANSACTION.

          (a) See the sections of the Offer to Purchase captioned "Summary",
          "Introduction", "Special Factors - The Merger", "Special Factors -
          Other Possible Purchases Of Shares", "Special Factors - Certain
          Effects Of The Offer And The Merger", "The Tender Offer - Terms Of
          The Offer; Expiration Date", "The Tender Offer - Acceptance For
          Payment And Payment For Shares", "The Tender Offer - Procedures For
          Accepting The Offer And Tendering Shares", "The Tender Offer -
          Withdrawal Rights" and "Certain Federal Income Tax Consequences".



ITEM 5.   PAST CONTACTS, TRANSACTIONS, NEGOTIATIONS AND AGREEMENTS.

          (a) See the sections of the Offer to Purchase captioned "Special
          Factors - Conflicts Of Interest - Executive Officers and Directors of
          the Company" and "Certain Information Concerning The Purchaser, Thermo
          Instrument And Thermo Electron - Certain Transactions" and Schedule I
          to the Offer to Purchase ("Members Of The Boards Of Directors And
          Executive Officers Of The Purchaser, Thermo Instrument And Thermo
          Electron").

          (b) See the sections of the Offer to Purchase captioned "Special
          Factors - Background To The Offer And The Merger", "Special Factors -
          Conduct Of The Company's Business After The Offer And The Merger",
          "Certain Information Concerning The Purchaser, Thermo Instrument And
          Thermo Electron - Certain Transactions" and Schedule II to the Offer
          to Purchase ("Information Concerning Transactions In The Common Stock
          Of The Company").

ITEM 6.   PURPOSE OF THE TRANSACTION AND PLANS OR PROPOSALS.

          (a) and (c)(1)-(7) See the sections of the Offer to Purchase captioned
          "Introduction", "Special Factors - Background To The Offer And The
          Merger", "Special Factors - Reasons For The Offer And The Merger",
          "Special Factors - The Merger", "Special Factors - Other Possible
          Purchases Of Shares", "Special Factors - Certain Effects Of The Offer
          And The Merger", "Special Factors - Conduct Of The Company's Business
          After The Offer And The Merger", "Special Factors - Conduct Of The
          Company's Business If The Offer Is Not Completed" and "The Merger;
          Appraisal Rights".

ITEM 7.   SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

          (a), (b) and (d) See the section of the Offer to Purchase captioned
          "Source And Amount Of Funds".

ITEM 8.   INTEREST IN SECURITIES OF THE SUBJECT COMPANY.

          (a) See the section of the Offer to Purchase captioned "Introduction"
          and Schedule I to the Offer to Purchase ("Members Of The Boards Of
          Directors And Executive Officers Of The Purchaser, Thermo Instrument
          And Thermo Electron").

          (b) See Schedule II to the Offer to Purchase ("Information Concerning
          Transactions In The Common Stock Of The Company").

ITEM 9.   PERSONS/ASSETS RETAINED, EMPLOYED, COMPENSATED OR USED.



          (a) See the sections of the Offer to Purchase captioned "Introduction"
          and "Fees And Expenses".

ITEM 10.  FINANCIAL STATEMENTS.

          (a) The financial statements of the Purchaser, Thermo Instrument and
          Thermo Electron Corporation, a Delaware corporation ("Thermo
          Electron"), are not material to the Offer.

          (b) The pro forma financial statements of the Purchaser, Thermo
          Instrument and Thermo Electron are not material to the Offer.

ITEM 11.  ADDITIONAL INFORMATION.

          (a)(1) None.

          (a)(2) See the sections of the Offer to Purchase captioned
          "Introduction", "The Tender Offer - Acceptance For Payment And Payment
          For Shares" and "The Tender Offer - Certain Legal Matters; Regulatory
          Approvals".

          (a)(3) See the section of the Offer to Purchase captioned "The Tender
          Offer - Certain Legal Matters; Regulatory Approvals".

          (a)(4) See the section of the Offer to Purchase captioned "Special
          Factors - Certain Effects Of The Offer And The Merger".

          (a)(5) None.

          (b) The information set forth in the Offer to Purchase and the Letter
          of Transmittal is incorporated herein by reference.

ITEM 12.   EXHIBITS.

          (a)(1) Offer to Purchase dated March 31, 2000.

          (a)(2) Letter of Transmittal.

          (a)(3) Notice of Guaranteed Delivery.

          (a)(4) Letter from the Dealer Managers to Brokers, Dealers, Commercial
          Banks, Trust Companies and Nominees.

          (a)(5) Letter to Clients for use by Brokers, Dealers, Commercial
          Banks, Trust Companies and Nominees.

          (a)(6) Summary Advertisement as published on March 31, 2000.



          (a)(7) Guidelines for Certification of Taxpayer Identification Number
          on Substitute Form W-9.

          (a)(8) Press Release issued by Thermo Instrument on January 31, 2000.

          (a)(9) Press Release issued by Thermo Electron on January 31, 2000.

          (a)(10) Press Release issued by Thermo Electron on March 6, 2000.

          (a)(11) Press Release issued by Thermo Instrument on March 31, 2000.

          (b) Loan Agreement dated as of March 1, 2000 between Thermo Electron
          and Thermo Instrument.

          (d) None.

          (g) Slide Presentation of Thermo Electron to Financial Analysts.

          (h) None.

ITEM 13. INFORMATION REQUIRED BY SCHEDULE 13E-3.

          Item 2. Subject Company Information.

               (d) See the section of the Offer to Purchase captioned "Price
               Range Of The Shares; Dividends".

               (e) See the sections of the Offer to Purchase captioned "The
               Company" and "Certain Information Concerning The Company".

               (f) See Schedule II to the Offer to Purchase ("Information
               Concerning Transactions In The Common Stock Of The Company").

          Item 4. Terms of the Transaction.

               (c) None.

               (d) See the section of the Offer to Purchase captioned "The
               Merger; Appraisal Rights" and Schedule III to the Offer to
               Purchase ("Section 262 Of The Delaware General Corporation
               Law").

               (e) See the section of the Offer to Purchase captioned "Certain
               Information Concerning The Company".

               (f) Not applicable.

          Item 5. Past Contacts, Transactions, Negotiations and Agreements.



               (c) See the sections of the Offer to Purchase captioned
               "Introduction" and "Special Factors - Background To The Offer And
               The Merger".

               (e) See the sections of the Offer to Purchase captioned "Special
               Factors - The Merger" and "Source And Amount Of Funds".

          Item 6. Purposes of the Transaction and Plans or Proposals

               (b) See the section of the Offer to Purchase captioned "Special
               Factors - The Merger".

               (c)(8) See the section of the Offer to Purchase captioned
               "Special Factors - Certain Effects Of The Offer And The Merger".

          Item 7. Purposes, Alternatives, Reasons and Effects.

               (a), (b) and (c) See the sections of the Offer to Purchase
               captioned "Introduction", "Special Factors - Background To The
               Offer And The Merger", "Special Factors - Reasons For The Offer
               And The Merger" and "Special Factors - Position Of Thermo
               Instrument And Thermo Electron As To Fairness Of The Offer And
               The Merger".

               (d) See the sections of the Offer to Purchase captioned "Special
               Factors - Certain Effects Of The Offer And The Merger", "Special
               Factors - Conduct Of The Company's Business After The Offer And
               The Merger", "Special Factors - Conduct Of The Company's Business
               If The Offer Is Not Completed", "Certain Federal Income Tax
               Consequences" and "The Merger; Appraisal Rights".

          Item 8. Fairness of the Transaction.

               (a), (b), (c), (d), (e) and (f) See the sections of the Offer to
               Purchase captioned "Special Factors - Background To The Offer
               And The Merger", "Special Factors - Position Of Thermo
               Instrument And Thermo Electron As To Fairness Of The Offer
               And The Merger", "Special Factors - Summary Of The Advisors'
               Analysis And Opinion", "Special Factors - Certain Projected
               Financial Data", "Special Factors - Other Possible Purchases
               Of Shares" and "Special Factors - The Merger".

          Item 9. Reports, Opinions, Appraisals and Negotiations.

               (a), (b) and (c) See the sections of the Offer to Purchase
               captioned "Special Factors - Summary Of The Advisors' Analysis
               And Opinion" and "Special Factors - Certain Projected Financial
               Data".

          Item 10. Source and Amount of Funds or Other Consideration.



               (c) See the section of the Offer to Purchase captioned "Fees And
               Expenses".

          Item 12. The Solicitation or Recommendation.

               (d) See the section of the Offer to Purchase captioned "Special
               Factors - Conflicts Of Interest".

               (e) Except for the positions of the member of the Special
               Committee of the Board of Directors of the Company and the Boards
               of Directors of Thermo Electron and Thermo Instrument as set
               forth in the sections of the Offer to Purchase captioned
               "Special Factors - Background To The Offer And The Merger" and
               "Special Factors Position Of Thermo Instrument And Thermo
               Electron As To Fairness Of The Offer And The Merger", the
               filing persons are not aware of any officer, director or
               affiliate of the Company or any person listed on Schedule I to
               the Offer to Purchase who has made a recommendation either in
               support of or against the Offer.

          Item 13. Financial Statements.

               (a) (1) The audited consolidated financial statements of the
               Company as of and for the fiscal years ended January 1, 2000 and
               January 2, 1999 are incorporated herein by reference to the
               Consolidated Financial Statements of the Company included as
               Exhibit 13 to the Company's Annual Report on Form 10-K for the
               fiscal year ended January 1, 2000 filed with the Securites and
               Exchange Commission (the "Commission") on March 9, 2000.

               (2) Not applicable.

               (3) See the section of the Offer to Purchase captioned "Certain
               Information Concerning The Company - Selected Consolidated
               Financial Information".

               (4) See the section of the Offer to Purchase captioned "Certain
               Information Concerning The Company - Selected Consolidated
               Financial Information".

               (b) The pro forma financial statements of the Company are not
               material to the Offer.

          Item 14. Persons/Assets Retained, Employed, Compensated or Used.

               (b) None.

          Item 16. Exhibits.

               (c) Opinion of J.P. Morgan Securities Inc. and The Beacon Group
               Capital Services, LLC dated January 29, 2000.



               (f) Statement of Appraisal Rights. See the section of the Offer
               to Purchase captioned "The Merger; Appraisal Rights" and
               Schedule III to the Offer to Purchase ("Section 262 Of The
               Delaware General Corporation Law").




                                    SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the
information set forth in this Statement is true, complete and correct.

                                          METRIKA ACQUISITION INC.

                                          BY: /s/ Earl R. Lewis
                                          --------------------------------------
                                               Name:    Earl R. Lewis
                                               Title: President

                                          THERMO INSTRUMENT SYSTEMS INC.

                                          BY: /s/ Earl R. Lewis
                                          --------------------------------------
                                               Name:    Earl R. Lewis
                                               Title: President and Chief
                                                      Executive Officer

                                          THERMO ELECTRON CORPORATION

                                          BY: /s/ Theo Melas-Kyriazi
                                          --------------------------------------
                                               Name:    Theo Melas-Kyriazi
                                               Title: Vice President and Chief
                                                         Financial Officer

Date: March 31, 2000




                                  EXHIBIT INDEX




EXHIBIT           DESCRIPTION

               
12(a)(1)          Offer to Purchase dated March 31, 2000

12(a)(2)          Letter of Transmittal

12(a)(3)          Notice of Guaranteed Delivery

12(a)(4)          Letter from the Dealer Managers to Brokers,
                  Dealers, Commercial Banks, Trust Companies and
                  Nominees

12(a)(5)          Letter to Clients for use by Brokers, Dealers,
                  Commercial Banks, Trust Companies and Nominees

12(a)(6)          Summary Advertisement as published on March 31, 2000

12(a)(7)          Guidelines for Certification of Taxpayer
                  Identification Number on Substitute Form W-9

12(a)(8)          Press Release issued by Thermo Instrument on January 31,
                  2000 (incorporated herein by reference to
                  Exhibit 99 to the Current Report on Form 8-K of
                  Thermo Instrument filed with the Commission on February 1,
                  2000)

12(a)(9)          Press Release issued by Thermo Electron on January
                  31, 2000 (incorporated herein by reference to
                  Exhibit 99 to the Current Report on Form 8-K of
                  Thermo Electron filed with the Commission on
                  February 1, 2000)

12(a)(10)         Press Release issued by Thermo Electron on March 6, 2000

12(a)(11)         Press Release issued by Thermo Instrument on March 31, 2000

12(b)             Loan Agreement dated as of March 1, 2000 between
                  Thermo Electron and Thermo Instrument

12(c)             Opinion of J.P. Morgan Securities Inc. and The
                  Beacon Group Capital Services, LLC dated January
                  29, 2000

12(d)             Not applicable

12(e)             Not applicable

12(f)             Summary of Appraisal Rights (Included in Exhibit
                  12(a)(1) in the section captioned "The Merger;
                  Appraisal Rights" and Schedule III to Exhibit 12(a)(1)
                  ("Section 262 Of The Delaware General Corporation
                  Law"))

12(g)             Slide Presentation of Thermo Electron to Financial
                  Analysts