MASTER PURCHASE AGREEMENT

         THIS MASTER PURCHASE  AGREEMENT  ("Agreement")  is made effective as of
December 28, 1995 by and between THERMO JARRELL ASH CORPORATION, a Massachusetts
corporation  whose  address  is  27  Forge  Parkway,   Franklin,   Massachusetts
02038-3148 ("TJA"),  and THERMO INSTRUMENT SYSTEMS INC., a Delaware  corporation
whose address is 504 Airport  Road,  Santa Fe, New Mexico 87504 and which is the
parent corporation of TJA ("Thermo Instrument") (TJA and Thermo Instrument being
sometimes  collectively  referred to herein as "Thermo"),  and ON-SITE ANALYSIS,
INC., a Georgia corporation whose address is 3125 Presidential Drive, Suite 130,
Atlanta, Georgia 30340-3907 ("OSA, Inc."), and TOP SOURCE TECHNOLOGIES,  INC., a
Delaware corporation whose address is 2000 PGA Boulevard, Suite 3200, Palm Beach
Gardens,  Florida  33408-2713  and which is the parent  corporation of OSA, Inc.
("Top Source") (OSA, Inc. and Top Source being sometimes  collectively  referred
to herein as "TSI").

                              W I T N E S S E T H:

         WHEREAS,  TSI and United  Testing  Group,  Inc., a Georgia  corporation
which is the  successor (by way of merger) to  Spectro/Metrics,  Inc., a Georgia
corporation,  and whose parent  corporation is Top Source  ("UTG"),  and TJA and
Nicolet Instrument Corporation, a Wisconsin corporation whose parent corporation
is Thermo  Instrument  ("Nicolet"),  have  each  contributed  certain  Technical
Contributions  (as hereinafter  defined) in the joint development of the On-Site
Analyzer (as hereinafter defined); and

         WHEREAS,  Top  Source  and  UTG  have  transferred  or  licensed  their
Technical  Contributions  to OSA, Inc.,  and Thermo  Instrument and Nicolet have
transferred  or  licensed  their  Technical   Contributions   to,  or  otherwise
authorized the use thereof by, TJA; and

         WHEREAS,  the parties  intend  from time to time  jointly to modify the
specifications   for  the  On-Site  Analyzer  in  order  to  create  specialized
instrumentation  (individually,  a  "Specialized  Unit" and,  collectively,  the
"Specialized  Units") for use in different commercial  applications  relating to
Oil Analysis (as hereinafter defined); and

         WHEREAS, OSA, Inc., in addition to its Technical Contributions, will be
contributing  to the  commercial  exploitation  of  the  Specialized  Units  the
marketing  expertise  of OSA,  Inc.,  and the  knowledge  of the business of Oil
Analysis  required  in order to  determine  which  commercial  applications  are
technologically  feasible and otherwise  appropriate for each  Specialized  Unit
which may be developed; and

         WHEREAS,  TJA,  in  addition to its  Technical  Contributions,  will be
contributing  to the  commercial  exploitation  of  the  Specialized  Units  the
manufacturing expertise of TJA required in order to

                                        1

<PAGE>



ensure that each Specialized Unit functions in substantial  conformance with the
Specialized Unit Specification (as hereinafter defined) applicable thereto, upon
the terms and  subject to the  conditions  more  particularly  set forth in this
Agreement; and

         WHEREAS,  the parties wish to  memorialize  their  agreement  regarding
their  rights and  obligations  with  respect to the  Specialized  Units and the
commercial exploitation thereof as hereinafter provided;

         NOW,  THEREFORE,  for and in  consideration  of the premises and mutual
covenants and agreements  hereinafter set forth, and for other good and valuable
consideration,  the receipt and sufficiency of which are hereby acknowledged and
accepted, the parties hereto do agree as follows:

1.       DEFINITIONS.

         In  addition to such other  terms as may be defined  elsewhere  in this
Agreement,  the following terms as used herein shall have the meanings  ascribed
in this Article:

         1.1      Customer means a person or entity who purchases, leases
or licenses a Specialized Unit from OSA, Inc. as contemplated by
the terms of this Agreement.

         1.2 Customer Site means a location at which a Specialized  Unit will be
installed as herein provided for Customer use.

         1.3 Instrument  Software means,  with respect to any  Specialized  Unit
developed hereunder,  that portion of the computer software operating system and
any application  software used to operate the  Specialized  Unit, in object code
form only,  developed  by or for (and owned or  licensed  by) TJA and all future
modifications  and  enhancements  thereto  developed  by or for  (and  owned  or
licensed  by) TJA,  all as  incorporated  in the  Specialized  Unit.  Instrument
Software  shall not include  the OSA,  Inc.  Software  or any other  proprietary
software of OSA, Inc.

         1.4  Integrated  Instrument  means any  integrated  apparatus  used for
analysis of mineral oils, synthetic oils and hydraulic fluids, which combines an
optical  emission  spectrometer  ("OES")  with  spark  excitation  and a Fourier
transform infrared  spectrometer  ("FTIR") in one cabinet with a single computer
control.

         1.5  Intellectual  Property  means  all  intellectual  property  rights
existing from time to time,  including  without  limitation any patents,  design
rights or registered  designs,  trademarks or service marks (and any application
throughout  the  world  or the  right to apply  therefor),  copyrights  (whether
registered or  unregistered,  and including moral rights),  know-how  (including
without  limitation   engineering  and  technical   know-how),   trade  secrets,
confidential


                                       -2-



<PAGE>





information,  any  business  name,  trade  name or style  or brand  name and any
merchandising rights.

         1.6  Oil  Analysis  means  the  testing  and  analysis  of any  and all
petrochemical-based  lubricants,  synthetic oils and hydraulic fluids in any and
all stages of  processing,  production or use,  including  (without  limitation)
extraction, refinement, product-in- use and waste, regardless of the industry or
purpose for which such  testing and analysis is  performed.  Petrochemical-based
fluids other than those identified in the preceding  sentence are not within the
scope of "Oil Analysis" and are excluded from the definition thereof.

         1.7      Operator's Manual means the written materials produced by
OSA, Inc. and supplied to a Customer in conjunction with any given
Specialized Unit instructing the Customer in the use of such
Specialized Unit.

         1.8  On-Site  Analyzer  or OSA means  the  Integrated  Instrument  (and
software  incorporated  therein,  including  without  limitation  the Instrument
Software and OSA, Inc. Software) described in the specifications attached hereto
as  Exhibit A  entitled  "'U'  Specification"  and  incorporated  herein by this
reference, as the same may be amended from time to time.

         1.9 OSA, Inc.  Software  means,  with respect to any  Specialized  Unit
developed hereunder,  that portion of the computer software operating system and
any application  software used to operate the  Specialized  Unit, in object code
form only,  developed  by or for (and owned or licensed  by) OSA,  Inc.  and all
future  modifications and enhancements thereto developed by or for (and owned or
licensed by) OSA, Inc., all as incorporated  in the Specialized  Unit. OSA, Inc.
Software shall not include Instrument Software or any other proprietary software
of TJA.

         1.10 Party or "party" means Thermo  considered as one party (or any one
or both  of TJA or  Thermo  Instrument,  as the  context  may  require)  and TSI
considered as one party (or any one or both of OSA,  Inc. or Top Source,  as the
context may require).

         1.11     Technical Contributions means, with respect to any
Specialized Unit developed hereunder, Intellectual Property
contributed respectively by OSA, Inc. (itself or as transferee or
licensee of Top Source and UTG) and TJA (itself or as transferee,
licensee, or authorized designee of Thermo Instrument and Nicolet)
in the development of the Specialized Unit.  Technology,


                                       -3-



<PAGE>





engineering and other technical know-how  constituting prior art existing within
the public domain as of the effective date of this Agreement  shall be expressly
excluded from the definition of Technical Contributions hereunder.

2.       SPECIALIZED UNIT ADDENDA.

         Upon the  development  of  specifications  mutually  acceptable  to the
parties for a Specialized  Unit which OSA, Inc. desires to purchase from TJA and
TJA  desires  to sell to  OSA,  Inc.  (as to each  such  Specialized  Unit,  the
"Specialized Unit Specification"), the parties shall execute an Addendum to this
Agreement,  in form  mutually  acceptable  to the parties (a  "Specialized  Unit
Addendum"),  setting forth the Specialized Unit  Specification  and the purchase
price  applicable  to  such  Specialized  Unit  (the  "Purchase  Price").   Each
Specialized Unit Addendum shall be a separate and enforceable  agreement,  shall
incorporate therein all of the terms and conditions of this Agreement, and shall
contain such additional terms and conditions as the parties mutually agree upon.


3.       OWNERSHIP OF SPECIALIZED UNITS AND RELATED INTELLECTUAL
PROPERTY.

         3.1      Technical Contributions, Etc.  Except to the extent
expressly otherwise provided in this Agreement, TJA and OSA, Inc.
shall each remain fully vested with all right, title and interest
(as owner, licensee or designee, as the case may be) in and to its
respective Technical Contributions.

         3.2 Marks.  Specialized  Units (and  related  services)  shall be sold,
leased, licensed, sublicensed, distributed and marketed as permitted herein only
under the  trademarks,  trade names,  service marks and trade dress of OSA, Inc.
(collectively,  the "OSA, Inc. Marks"). Specialized Units (and related services)
shall not be sold, leased, licensed, sublicensed,  distributed or marketed under
the  trademarks,  trade  names,  service  marks  or trade  dress of TJA,  Thermo
Instrument  or Nicolet  (collectively,  the "TJA  Marks").  Notwithstanding  the
foregoing  provisions of this Section 3.2, OSA, Inc. shall not remove or obscure
any notice of  copyright,  patent,  trademark,  trade  secret or  restricted  or
limited rights which may be contained on the Instrument  Software  and/or any of
TJA's Technical  Contributions.  For purposes of this  Agreement,  the OSA, Inc.
Marks and the TJA Marks are  referred to  collectively  as the "Marks." No party
shall use any of the Marks of another  party  hereto  without the prior  written
consent of the other party. No


                                       -4-



<PAGE>





party  shall  register,  agree  to  register  or  assist  any  other  person  in
registering any Marks of another party hereto in any  jurisdiction in the world.
Each  party  acknowledges  that the other  has the  exclusive  right,  title and
interest in and to such other party's  respective  Marks. Each party agrees that
it will not use, without the other's prior written consent,  any Marks which are
likely  to be  similar  to or  confused  with  the  Marks  of the  other  party.
Notwithstanding the foregoing, OSA, Inc. shall have the right to identify TJA as
the  manufacturer of any Specialized Unit developed  hereunder,  and to identify
any  TJA  Marks  affixed  by  TJA to  components  of the  Specialized  Unit,  in
presentations  marketing the  Specialized  Unit, and in sales,  advertising  and
marketing materials for the Specialized Unit;  provided,  however,  that (i) TJA
shall  have  the  right to  pre-approve  in  writing  all  such  written  sales,
advertising and marketing  materials  referencing TJA and/or any TJA Marks prior
to the  dissemination  of such  materials by OSA,  Inc.,  (ii) except where such
identification  is  required  by law (and in such  cases,  TJA shall be notified
prior to the  making of such  identification),  TSI  shall  obtain  TJA's  prior
written  consent to identify TJA or any TJA Marks in relation to the Specialized
Unit in any press  release or public  statement,  including  without  limitation
those to the financial  community,  and (iii) if TJA determines,  in good faith,
that the TJA Marks are being used by OSA, Inc. in a manner which is  detrimental
to the reputation of TJA (including  without  limitation in connection  with the
sale, leasing, licensing or sublicensing of one or more Specialized Units to any
Customer  for  an  application  as to  which  the  applicable  Specialized  Unit
Specification   is,  in  TJA's  sole   discretion,   inadequate   or   otherwise
inappropriate),  then, in such event,  TJA shall so notify OSA,  Inc.,  and OSA,
Inc. shall immediately  remove all TJA Marks from Specialized Units then in OSA,
Inc.'s  possession and thereafter  shall not identify TJA as the manufacturer of
the Specialized  Units nor otherwise use the TJA Marks in any manner,  including
without   limitation  in   connection   with  the  sale,   leasing,   licensing,
sublicensing,  distribution  or marketing of the  Specialized  Units (or related
services).  The  consents  required  of TJA  pursuant to the  provisions  of the
immediately  preceding  sentence shall not  unreasonably be withheld or delayed,
provided TJA expressly  reserves the right to make  determinations in TJA's sole
discretion to the extent set forth in clause (iii) of said sentence.

4.       USE OF TECHNICAL CONTRIBUTIONS, ETC.

         4.1      General.  Except to the extent permitted by the terms of
this Agreement, neither party may use the Technical Contributions


                                       -5-



<PAGE>





of the other party in any manner whatsoever  without the express written consent
of such other party.

         4.2      Instrument Software.  TJA hereby grants to OSA, Inc. a
nontransferable (except to the extent expressly otherwise provided
herein), nonexclusive right and license to use the Instrument
Software, subject to the following:

                  4.2.1  Use of the Instrument Software by OSA, Inc. shall
be solely in connection with the ordinary operation of a
Specialized Unit, as specified in the applicable Operator's Manual
 .

                  4.2.2 OSA, Inc.  shall have the right to grant to any Customer
(and  shall  in any  event  not  grant  rights  greater  than)  a  nonexclusive,
nontransferable  sublicense  (expressly  excluding  the right by the Customer to
further  sublicense)  for the sole  purpose of allowing  the Customer to use the
Instrument Software in connection with the ordinary operation of the Specialized
Unit, as specified in the Operator's Manual.

                  4.2.3 The license to OSA, Inc., and any Customer's sublicense,
shall encompass only object code.

                  4.2.4  OSA,  Inc.  is  prohibited  from,  and  any  Customer's
sublicense  shall  prohibit  the  Customer  from,  (a)  copying,   accessing  or
downloading the Instrument Software,  other than in connection with the ordinary
operation of the Specialized Unit in accordance with the Operator's  Manual; (b)
decompiling,  disassembling or reverse engineering the Instrument Software;  (c)
removing or obscuring any notice of copyright,  patent, trademark,  trade secret
or  restricted  or limited  rights;  or (d)  removing  or  obscuring  any export
restriction or similar notice contained on the Instrument Software.

         4.3      OSA, Inc. Software.  OSA, Inc., hereby grants to TJA a
nontransferable, nonexclusive right and license to use the OSA,
Inc. Software, subject to the following restrictions:

                  4.3.1 TJA shall  have the right  only to copy and use the OSA,
Inc.  Software solely in connection with (a) developing the Instrument  Software
for purposes of this  Agreement for the mutual benefit of the parties hereto and
(b)  installation  of the OSA,  Inc.  Software into  Specialized  Units prior to
shipment by TJA to OSA, Inc. or Customers.



                                       -6-



<PAGE>







                  4.3.2 Without  limiting the  foregoing,  TJA agrees not to (a)
copy, access or download the OSA, Inc. Software;  (b) decompile,  disassemble or
reverse  engineer the OSA,  Inc.  Software;  (c) remove or obscure any notice of
copyright, patent, trademark, trade secret, restricted or limited rights; or (d)
remove or obscure any export restriction or similar notice contained on the OSA,
Inc.
Software.

5.       MANUFACTURING.

         5.1  Manufacture  by  TJA.  TJA  shall  manufacture  Specialized  Units
developed hereunder  (including,  without limitation,  installing the Instrument
Software  thereon) and supply such Specialized  Units to OSA, Inc. in accordance
with the terms and conditions of this Agreement.

         5.2  Specifications.  IT IS  EXPRESSLY  UNDERSTOOD  AND  AGREED  BY THE
PARTIES HERETO THAT ANY MODIFICATION OF THE SPECIALIZED UNIT  SPECIFICATION MUST
BE APPROVED IN WRITING BY BOTH THE  PRESIDENT  OF TJA AND THE  PRESIDENT OF OSA,
INC.,  WHICH APPROVAL MAY BE WITHHELD BY EITHER TJA OR OSA, INC. IN SUCH PARTY'S
SOLE AND ABSOLUTE  DISCRETION,  IT BEING  EXPRESSLY  UNDERSTOOD AND AGREED THAT,
EXCEPT AS MAY BE  EXPRESSLY  AGREED TO BY THE PARTIES AS PROVIDED  ABOVE IN THIS
SECTION 5.2,  NEITHER TJA NOR THERMO  INSTRUMENT HAS ANY  OBLIGATION  UNDER THIS
AGREEMENT,  EXPRESS OR IMPLIED, TO MANUFACTURE,  DELIVER OR OTHERWISE PROVIDE TO
OSA,  INC. OR TOP SOURCE ANY  SPECIALIZED  UNIT WHICH DIFFERS IN ANY MANNER FROM
THE SPECIALIZED UNIT SPECIFICATION  ORIGINALLY  DEVELOPED AND AGREED UPON BY THE
PARTIES WITH RESPECT THERETO.

         6   RIGHT TO MODIFY.

         Notwithstanding any provision herein to the contrary,  it is understood
and agreed by the parties hereto that OSA, Inc.  shall have the right,  alone or
in conjunction with any third party, to modify (including  without limitation to
add or substitute  component parts) in any manner any Specialized Unit purchased
by OSA,  Inc.  hereunder  (so  long as OSA,  Inc.  does  not  infringe  upon the
Instrument Software or any of TJA's Technical Contributions); provided, however,
that any such modification  shall  immediately void and cancel,  with respect to
the Specialized Unit so modified, (i) all Installation obligations under Section
9.1, (ii) all maintenance obligations under Section 9.2 and (iii) all warranties
under Section 10.1.1.  . Upon the  modification of any Specialized Unit pursuant
to the provisions of this Article 6, OSA, Inc.


                                       -7-



<PAGE>





immediately  shall  remove  all TJA Marks  therefrom  and  thereafter  shall not
identify TJA as the  manufacturer of the same nor otherwise use the TJA Marks in
any manner with respect to such modified  Specialized  Unit,  including  without
limitation  in  connection  with the  sale,  leasing,  licensing,  sublicensing,
distribution or marketing thereof.



7.        SHIPMENT;  DELIVERY.

                  7.1 Site Survey  Report.  OSA, Inc.  agrees to deliver to TJA,
prior to the week in which an order for  Specialized  Units  hereunder  is to be
shipped by TJA, a completed  Site Survey Report with respect to each Customer to
which such order relates in substantially  the form of Exhibit B attached hereto
and  incorporated  herein by this  reference (the "Site Survey  Report").  It is
understood  and agreed that one purpose of such Site Survey  Report is to enable
TJA to contact any Customer  directly,  whether by mail,  telephone,  facsimile,
computer  modem or  otherwise,  in order to relay to such  Customer  information
regarding the use,  operation and/or  maintenance of the Specialized  Unit(s) in
such Customer's possession.

         7.2  Terms  and  Conditions.  No terms or  conditions  of any order for
Specialized  Units  other  than  the  terms  and  conditions  set  forth in this
Agreement shall apply to purchases of Specialized Units by OSA, Inc.

         7.3  Shipment.  Specialized  Units shall be shipped to the  destination
specified  by OSA,  Inc.,  on an F.O.B.  destination  basis..  Unless  otherwise
requested by OSA, Inc., TJA shall select the carrier. Partial shipments shall be
permitted and TJA may invoice each shipment separately. All shipping costs shall
be borne by OSA, Inc., and all Specialized  Units shall be insured in transit by
TJA (unless otherwise  requested by OSA, Inc.), at the expense of OSA, Inc. OSA,
Inc.  shall  reimburse TJA for such shipping and insurance  costs  promptly upon
demand.  The delivery date for any given shipment of  Specialized  Units will be
mutually agreed upon by the parties at the time of TJA's acceptance of the order
therefor.

         7.4      Return Authorization.  No Specialized Unit shipped by TJA
may be returned without TJA's written permission.  All shipping
expenses on returned Specialized Units will be paid by the party
who necessitated the return (the "Responsible Party").  In the


                                       -8-



<PAGE>





event such expenses are not paid by the Responsible  Party,  the other party may
invoice the Responsible Party therefor.

         7.5 Shortages; Damages in Transit. If the quantity of Specialized Units
received by OSA, Inc.  shall be less than the quantity  shown in the  applicable
invoice,  or if the  Specialized  Units  received by OSA,  Inc.  shall have been
damaged in transit,  OSA, Inc.  shall,  within twenty (20) days after receipt of
such goods,  give written  notice of such shortage or damage to the agent of the
delivery  carrier in order to permit  written  verification  of the  shortage or
damage by the  delivery  carrier  and  substantiate  a formal  claim when and if
presented. OSA, Inc. shall promptly send a copy of such notice to TJA.

         7.6 Title and Risk of Loss.  Subject to any claims  pursuant to Section
7.5, title to and post-delivery risk of loss for Specialized Units shall pass to
OSA, Inc. upon delivery of the Specialized Units to the designated  destination;
provided,  however,  that title to the  Instrument  Software  shall at all times
remain with TJA (or its licensor). OSA, Inc. shall reasonably cooperate with TJA
in any documentation  and proof of loss claims promptly  presented by TJA to the
appropriate carrier and/or insurer.

         7.7 Title Matters.  OSA, Inc. shall have  flexibility in its discretion
to arrange for title to any  Specialized  Unit to be  transferred at any time to
any third party, including, without limitation, finance corporations, subject to
compliance with the provisions of Section 14.2 below. Written notice of any such
transfer,  together  with the  identity  of the  transferee,  shall be  promptly
presented to TJA by OSA, Inc.

8.       PAYMENT TERMS.

         8.1 Payments  Net. An amount equal to forty  percent (40%) of the total
Purchase Price allocable to a given order for Specialized  Units hereunder shall
be paid by OSA, Inc. at the time of the order. The balance of the Purchase Price
will be paid  within  thirty (30) days after the date of  shipment.  All amounts
payable  by OSA,  Inc.  to TJA  under  this  Agreement  shall be paid net of all
freight charges,  insurance premiums, taxes (including without limitation sales,
value-added  and use taxes,  but  excluding  taxes  based on TJA's net  income),
tariffs  and  other  governmental  charges,   payment  of  which  shall  be  the
responsibility of OSA, Inc. If TJA is required to pay any such charge,  premium,
tax, tariff or other charge based on goods sold or any services  performed under
this Agreement, then the same (together with any penalties and/or


                                       -9-



<PAGE>





interest thereon) shall be billed to and paid by OSA, Inc.  All
payments hereunder shall be made in U.S. dollars.

         8.2 Late Payment Charges.  In addition to any other remedies  available
to TJA  hereunder,  if OSA,  Inc.  fails to pay any amounts when due,  OSA, Inc.
shall pay TJA interest on such overdue amounts at the rate of 2.0% per month (or
the  highest  rate  permitted  by law,  if lower)  from the date due until  paid
(calculated on the basis of a thirty  (30)-day month and pro-rated on a per diem
basis with respect to any partial month),  together with all costs and expenses,
including  without  limitation  reasonable  attorneys' fees,  incurred by TJA in
collecting such overdue amounts.

         8.3      OSA, Inc. Pricing.  OSA, Inc. shall be free to establish
its own pricing for Specialized Units sold, leased or licensed to
Customers and shall have no obligation whatsoever to TJA to account
for any differential relative to the applicable Purchase Price
paid to TJA therefor.

9.       INSTALLATION, TRAINING AND MAINTENANCE.

         9.1      Installation.

                  9.1.1   Installation   Obligation.   TJA  shall  install  each
Specialized Unit at the applicable Customer Site ("Installation") located within
the United  States  within  twenty  (20)  business  days after  delivery  of the
Specialized  Unit to the Customer  Site.  TJA may, in its  discretion and for an
additional  fee as  specified  in Section  9.1.3,  arrange for  Installation  at
Customer  Sites  outside  of  the  United  States.   TJA  may   subcontract  its
Installation obligations hereunder to a qualified subcontractor.

                  9.1.2 Customer Site. Notwithstanding the provisions of Section
9.1.1 above,  TJA's  Installation  obligation  need not be  completed  until the
latest to occur of (a) the  expiration  of the twenty (20)  business  day period
referenced  in Section  9.1.1  above;  (b) the second  (2nd)  business day after
receipt by TJA of the Site Survey Report  referenced in Section 7.1 above or (c)
the fourteenth  (14th) day after receipt by TJA of written notice from OSA, Inc.
that the following  conditions have been satisfied:  (i) the Customer Site is in
compliance with the site specifications  listed on Exhibit C attached hereto and
incorporated  herein by this reference and is otherwise safe and appropriate for
Installation;  and (ii) any third-party equipment to be used in conjunction with
the  Specialized  Unit  has been  reasonably  approved  by TJA and is  operating
according to the manufacturer's specifications. TJA or


                                      -10-



<PAGE>





its designated subcontractor shall perform the unpacking of the Specialized Unit
at the Customer  Site. On the date scheduled for  Installation,  OSA, Inc. shall
cause appropriate personnel of the Customer or OSA, Inc. or both to be available
to cooperate with TJA,  allowing TJA to use without charge any of the Customer's
equipment and facilities which TJA reasonably deems necessary for  Installation.
TJA shall give OSA, Inc. and/or the Customer sufficient advance  notification of
personnel  required for completion of the Installation.  The Customer Site shall
remain   accessible  to  TJA  throughout  the  period  of   Installation.   Upon
Installation  of a Specialized  Unit,  TJA or its  designated  subcontractor  or
agent,  as the  case  may be,  shall  perform  TJA's  standard  acceptance  test
procedures  to  confirm  that  the  Specialized  Unit  operates  in  substantial
conformance with the Specialized Unit  Specification  applicable  thereto.  Upon
successful completion of the aforesaid acceptance test procedures,  Installation
of the Specialized Unit shall be deemed complete.

                  9.1.3  Installation Fee.  Specialized Units shall be installed
by TJA free of charge in the United States.  If TJA in its discretion  agrees to
install a  Specialized  Unit  outside of the United  States,  TJA will charge an
installation fee in accordance with TJA's then current rates (the  "Installation
Fee").  The terms and  conditions  of Section  9.1.2 shall be  applicable to any
Installation to be performed by TJA outside of the United States.

                  9.1.4  Reinstallation.  In the  event a  Customer  desires  to
relocate a Specialized  Unit previously  installed by TJA, TJA shall install the
Specialized   Unit  at  the  new   Customer   Site  within  the  United   States
("Reinstallation"),  provided  that the terms and  conditions  of Section  9.1.2
above are satisfied with respect to the Reinstallation at the new Customer Site.
TJA shall  charge a fee,  payment of which  shall be the  responsibility  of the
Customer,  for  Reinstallation  in accordance with TJA's then current rates (the
"Reinstallation Fee").

                  9.1.5  Unauthorized Installation or Reinstallation.  OSA,
                         -------------------------------------------
Inc. shall have the right to elect to have the Installation or
Reinstallation of any Specialized Unit performed by OSA, Inc. or
any third party, including without limitation a Customer; provided,
however, that any Installation or Reinstallation of a Specialized
Unit at a Customer Site or any other location by any person or
entity other than TJA or TJA's designated subcontractor or agent
without the express written consent of TJA, signed by the President
of TJA and specifically referencing this Section 9.1.5. (an
"Unauthorized Installation"), shall automatically invalidate and


                                      -11-



<PAGE>





void  any TJA  warranty  with  respect  to such  Specialized  Unit.  TJA  HEREBY
DISCLAIMS ALL LIABILITY FOR ANY AND ALL CLAIMS, LOSSES, COSTS AND DAMAGES TO THE
EXTENT  ARISING  FROM  OR  ATTRIBUTABLE  TO  ANY  UNAUTHORIZED  INSTALLATION  OR
REINSTALLATION OF A SPECIALIZED UNIT.

         9.2  Maintenance.  OSA,  Inc.  agrees  to  retain  TJA to  provide  all
maintenance  with respect to Specialized  Units  manufactured or supplied by TJA
hereunder,   provided   TJA's   maintenance   services  are   competitive.   The
determination  as to  whether  or  not  the  maintenance  services  of  TJA  are
competitive  for  purposes of this  Section 9.2 shall be based upon such factors
as,  without  limitation,  timeliness  of  performance,  price and  professional
competence.  If OSA, Inc. requests that TJA provide all maintenance with respect
to Specialized  Units  manufactured or supplied by TJA hereunder,  TJA agrees to
provide  the same in  accordance  with  the  terms  of  TJA's  standard  form of
maintenance   agreement   (whether  or  not  TJA's   maintenance   services  are
competitive).  Payment for maintenance  services provided by TJA hereunder shall
be made by OSA, Inc. to TJA on a time and materials  basis at TJA's then current
rates.  TJA  may  subcontract  any  such   maintenance   services  to  qualified
subcontractors.  In the event that TJA's services are not competitive, OSA, Inc.
shall have the right to elect to obtain  said  maintenance  directly  from third
party vendors.  In the event that OSA, Inc.  contracts with any party other than
TJA to provide such maintenance services, OSA, Inc. agrees to defend,  indemnify
and hold  harmless  TJA,  its parent,  subsidiaries  and  affiliates  (including
without  limitation  Thermo  Instrument)  from and  against  any and all losses,
damages,  liabilities  and expenses  (including  without  limitation  reasonable
attorneys' fees and  disbursements  and court costs) incurred in connection with
third party claims or suits,  whether based in statute,  contract,  tort, strict
liability, breach of warranty or otherwise, to the extent arising, or alleged by
such third party  claimant to arise,  by reason of the acts or  omissions of any
such third party service provider.  It is understood and agreed that in no event
shall OSA, Inc., or any third party service provider retained by OSA, Inc., have
any right to the use of any diagnostic software owned by, or otherwise developed
on behalf of, TJA or Thermo Instrument.  TJA shall have no obligation to provide
service  manuals to OSA, Inc. or to any third party service  provider.  If it is
determined  that TJA's  maintenance  services  are  competitive  with respect to
certain  geographic areas and not others,  and OSA, Inc. elects to contract with
one or more third party service  providers  with respect to any such  geographic
area or areas as to which TJA's services are not competitive,  TJA shall in such
event have the right to elect not to provide  maintenance  services with respect
to Specialized Units


                                      -12-



<PAGE>





located in any remaining areas.

10.      WARRANTY AND LIMITATION OF LIABILITY.

         10.1     Warranties to OSA, Inc.

                  10.1.1 TJA warrants to OSA,  Inc. that the  Specialized  Units
(including,  without  limitation,  the Instrument  Software)  purchased from TJA
shall (a) upon initial  delivery be free from material defects in workmanship or
materials and (b) upon initial delivery and for a period of six (6) months after
initial  shipment (the "Warranty  Period")  operate  substantially in accordance
with the Specialized  Unit  Specification  applicable  thereto when subjected to
normal,  proper and  intended  usage.  TJA agrees  during the  Warranty  Period,
provided it is promptly notified in writing upon the discovery of any defect, to
repair or replace, at its option, free of charge, defective Specialized Units so
as to cause the same to conform to the  warranties  set forth in clauses  (a) or
(b) above, as the case may be, and such repair or replacement  shall  constitute
the sole and exclusive remedy for breach of any such warranty. Replacement parts
may be new or  refurbished,  at the  election  of TJA.  All costs for  returning
defective   Specialized   Units  to  TJA  shall  be  paid  by  OSA,  Inc.,  with
reimbursement  of such costs to be made by TJA to OSA,  Inc.  within thirty (30)
days following TJA's receipt of an invoice and reasonable back-up  documentation
therefor.  Notwithstanding  anything to the contrary contained herein, TJA makes
no warranties  (INCLUDING  WITHOUT  LIMITATION  WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR ANY  PARTICULAR  PURPOSE)  with respect to  equipment,  materials or
software  (including without limitation the OSA, Inc. Software) not manufactured
by TJA,  Thermo  Instrument,  or any parent,  subsidiary or affiliate of either.
Lamps,  mercury  bulbs and other minor  expendable  items are further  expressly
excluded   from  this   warranty.   TJA  agrees  to  assign  to  OSA,  Inc.  any
manufacturer's  warranty relating to any such excluded equipment,  materials and
software,  to the  extent the same is  assignable.  If TJA  determines  that any
Specialized  Unit for which OSA,  Inc. or any  Customer has  requested  warranty
service is not  covered  by the terms of the  warranty  under  clause (a) or (b)
above,  OSA, Inc. shall pay or reimburse to TJA all costs of  investigating  and
responding to such request at TJA's then  prevailing  time and materials  rates.
ANY  INSTALLATION,   MAINTENANCE,  REPAIR,  SERVICE,  ALTERATION,   MODIFICATION
(PURSUANT  TO THE TERMS OF ARTICLE 6 ABOVE OR  OTHERWISE),  RELOCATION  OR OTHER
TAMPERING TO OR WITH A SPECIALIZED  UNIT PERFORMED BY ANY PERSON OR ENTITY OTHER
THAN TJA OR  TJA's  DESIGNATED  SUBCONTRACTOR  OR AGENT  WITHOUT  TJA'S  WRITTEN
APPROVAL SIGNED BY THE PRESIDENT OF TJA AND


                                      -13-



<PAGE>





SPECIFICALLY  REFERENCING THIS SECTION 10.1.1,  OR ANY USE OF REPLACEMENT  PARTS
SUPPLIED BY ANY PARTY OTHER THAN TJA WITHOUT  TJA'S WRITTEN  APPROVAL  SIGNED BY
THE PRESIDENT OF TJA AND SPECIFICALLY  REFERENCING THIS SECTION 10.1.1 (IT BEING
UNDERSTOOD AND AGREED THAT REPLACEMENT PARTS DELIVERED  DIRECTLY TO OSA, INC. OR
TO ANY CUSTOMER BY TJA, TJA's DESIGNATED SUBCONTRACTOR OR AGENT OR A THIRD PARTY
VENDOR AT THE  DIRECTION OF TJA WILL BE DEEMED TO HAVE BEEN  SUPPLIED BY TJA FOR
PURPOSES  OF THIS  SECTION  10.1.1),  SHALL  IMMEDIATELY  VOID  AND  CANCEL  ALL
WARRANTIES  WITH  RESPECT  TO SUCH  SPECIALIZED  UNITS (BUT SHALL NOT IMPAIR ANY
VALID  WARRANTY  CLAIMS  THERETOFORE  ACCRUED WITH  RESPECT TO SUCH  SPECIALIZED
UNITS).


                  10.1.2 TJA warrants that the Instrument Software and Technical
Contributions  of TJA do not violate or infringe the United States  Intellectual
Property rights of any third party.

                  10.1.3  EXCEPT AS EXPRESSLY  PROVIDED IN THIS  AGREEMENT,  TJA
DISCLAIMS ALL  WARRANTIES,  WHETHER  EXPRESS OR IMPLIED,  ORAL OR WRITTEN,  WITH
RESPECT TO THE SPECIALIZED UNITS,  INCLUDING,  WITHOUT  LIMITATION,  ALL IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.



         10.2     Limitation of Liability.

                  10.2.1 (a) TJA's  LIABILITY  FOR  DAMAGES TO OSA,  INC. OR ANY
CUSTOMER FOR ANY BREACH OF WARRANTY CLAIM  HEREUNDER  SHALL NOT EXCEED THE PRICE
PAID FOR THE SPECIALIZED UNIT TO WHICH SUCH BREACH RELATES; AND (b) TJA SHALL IN
NO EVENT BE  LIABLE  FOR ANY  SPECIAL,  INCIDENTAL,  INDIRECT  OR  CONSEQUENTIAL
DAMAGES,  INCLUDING WITHOUT LIMITATION LOSS OF DATA, PROFITS OR USE, ARISING OUT
OF OR IN  CONNECTION  WITH  THIS  AGREEMENT,  INCLUDING  WITHOUT  LIMITATION  IN
CONNECTION WITH THE USE OR PERFORMANCE OF THE SPECIALIZED UNITS.
                  10.2.2 IN NO EVENT SHALL TJA BE LIABLE TO  CUSTOMERS  OR OTHER
THIRD PARTIES FOR, AND, SUBJECT TO THE LIMITATIONS IN SECTION 10.2.3,  OSA, INC.
SHALL  INDEMNIFY,  DEFEND AND HOLD  HARMLESS TJA, ITS PARENT,  SUBSIDIARIES  AND
AFFILIATES (INCLUDING WITHOUT LIMITATION THERMO INSTRUMENT AND NICOLET) FROM AND
AGAINST, ANY DAMAGES TO THE EXTENT (a) CAUSED BY ANY INSTALLATION,  MAINTENANCE,
REPAIR,  SERVICE,  ALTERATION,  MODIFICATION (PURSUANT TO THE TERMS OF ARTICLE 6
ABOVE OR OTHERWISE),  RELOCATION OR OTHER  TAMPERING TO OR WITH ANY  SPECIALIZED
UNIT PERFORMED BY ANY PARTY OTHER THAN TJA OR TJA's DESIGNATED  SUBCONTRACTOR OR
AGENT  WITHOUT  TJA'S  WRITTEN  APPROVAL  SIGNED  BY THE  PRESIDENT  OF TJA  AND
SPECIFICALLY


                                      -14-



<PAGE>





REFERENCING THIS SECTION 10.2.2;  (b) DUE TO A CUSTOMER'S FAILURE TO OBSERVE THE
SAFETY  INSTRUCTIONS   ACCOMPANYING  ANY  SPECIALIZED  UNIT,  INCLUDING  WITHOUT
LIMITATION  THOSE  CONTAINED  IN THE  OPERATOR'S  MANUAL OR DUE TO THE  CUSTOMER
HAVING  ALTERED,  OBSCURED  OR  REMOVED  WARNING  OR OTHER  LABELS OR  MATERIALS
PROVIDED  BY TJA;  (c) DUE TO THE NATURE OR CONTENT  OF THE  DIAGNOSTIC  DATA OR
OTHER RESULTS GENERATED OR PRODUCED BY THE OSA, INC. SOFTWARE; (d) DUE TO USE OR
STORAGE OF AN UNPACKED  SPECIALIZED UNIT IN A PHYSICAL  ENVIRONMENT WHICH IS NOT
IN CONFORMANCE WITH THE OPERATING  ENVIRONMENT DESCRIBED IN THE SPECIALIZED UNIT
SPECIFICATION  APPLICABLE  THERETO;  OR (e) DUE TO ANY  SPECIAL,  INCIDENTAL  OR
CONSEQUENTIAL  DAMAGES,  INCLUDING WITHOUT  LIMITATION LOSS OF DATA,  PROFITS OR
USE,  IN  CONNECTION  WITH  THE  USE OR  PERFORMANCE  OF ANY  SPECIALIZED  UNIT;
PROVIDED,  HOWEVER,  THAT OSA, INC.  SHALL HAVE NO LIABILITY  UNDER THIS SECTION
10.2.2 TO THE EXTENT ANY DAMAGES ARE  ATTRIBUTABLE  TO THE NEGLIGENCE OR WILLFUL
MISCONDUCT OF TJA, OR ITS PARENT, AFFILIATES, EMPLOYEES, AGENTS, REPRESENTATIVES
OR CONTRACTORS. The foregoing provisions of this Section 10.2.2 are not intended
to limit the express terms of any warranty set forth herein,  including  without
limitation  in  clause  (b)  of  Section  10.1.1  above  regarding   substantial
conformance  of a  Specialized  Unit  with the  Specialized  Unit  Specification
applicable thereto during the Warranty Period;  provided,  however,  that to the
extent any warranty claim made against TJA is  attributable to the occurrence of
any one or more of the events  enumerated in clauses (a) through (e) above, OSA,
Inc. shall  indemnify TJA for all costs incurred by TJA in connection  with such
claim.

     10.2.3 OSA, INC.  SHALL IN NO EVENT BE LIABLE FOR ANY SPECIAL,  INCIDENTAL,
INDIRECT OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION LOSS OF PROFITS,
ARISING OUT OF THIS AGREEMENT.

         10.3     Warranty to TJA.  OSA, Inc. warrants that the OSA, Inc.
Software and Technical Contributions of OSA, Inc. do not violate or
infringe the United States Intellectual Property rights of any
third party.

11.      MARKETING BY OSA, INC.

         11.1     Marketing.  OSA, Inc. shall use its best efforts to
market and promote the Specialized Units and to maximize its sales,
leases or licenses of Specialized Units.

         11.2     [Intentionally deleted.]




                                      -15-



<PAGE>





         11.3  Information  Regarding  Specialized  Units.  OSA, Inc. shall: (a)
provide  pertinent  information  concerning the Specialized Units to prospective
Customers;  (b) promptly  present to TJA complaints  concerning any  Specialized
Unit which OSA, Inc. receives from Customers; (c) remain reasonably informed and
knowledgeable  concerning  the function,  specifications  and  advantages of the
Specialized Units; (d) avoid deceptive,  misleading or unethical  practices that
are  detrimental  to  TJA,  Thermo  Instrument  and/or  any  one or  more of the
Specialized Units; (e) make no false or misleading  representations  with regard
to TJA, Thermo Instrument  and/or any one or more of the Specialized  Units; (f)
not publish or employ,  or cooperate in the  publication  or employment  of, any
misleading  or  deceptive  advertising  material  with  regard  to  TJA,  Thermo
Instrument  and/or  any one or more of the  Specialized  Units;  and (g) make no
representations,  warranties  or  guarantees  to  Customers or to the trade with
respect to the  specifications,  features or  capabilities of any one or more of
the Specialized  Units that are inconsistent with this Agreement and the various
Exhibits attached hereto or the warranties provided herein.

         11.4 Specialized Unit Applications.  It is understood and agreed by the
parties  hereto that the  identification  of Customers  to whom the  Specialized
Units are to be sold,  leased or licensed,  and the selection of the  commercial
applications for and  environments in which any given  Specialized Unit is to be
utilized,  shall be determined  exclusively  by OSA, Inc. in the exercise of its
sole  discretion.  TJA MAKES NO  REPRESENTATIONS  OR  WARRANTIES  OF ANY KIND OR
NATURE THAT THE  FUNCTIONALITY OF ANY SPECIALIZED UNIT IS ADEQUATE,  SUITABLE OR
OTHERWISE  APPROPRIATE,  FROM A  TECHNOLOGICAL  STANDPOINT OR OTHERWISE,  IN THE
CONTEXT OF ANY CURRENTLY  CONTEMPLATED AND/OR FUTURE  APPLICATIONS  THEREFOR AND
HEREBY DISCLAIMS ALL LIABILITY  ARISING FROM OR IN CONNECTION WITH THE ADEQUACY,
SUITABILITY OR  APPROPRIATENESS OF SUCH FUNCTIONALITY FOR ANY SUCH APPLICATIONS.
The  foregoing  provisions  of this  Section  11.4 are not intended to limit the
express  terms of the warranty  set forth in clause (b) of Section  10.1.1 above
regarding  substantial  conformance of each Specialized Unit developed hereunder
with the applicable Specialized Unit Specification during the Warranty Period.

12.      CUSTOMER AGREEMENT.

         No Specialized Unit shall be sold,  leased,  licensed or sublicensed by
OSA,  Inc.  to any  Customer  until  such time as a form of  customer  agreement
mutually  acceptable  to OSA,  Inc.  and TJA, in the  exercise  of each  party's
reasonable discretion, has been


                                      -16-



<PAGE>





created (the "Customer  Agreement").  OSA, Inc. agrees to cause each Customer to
execute a Customer  Agreement  prior to the  delivery  to such  Customer  of any
Specialized Unit hereunder.  Upon execution of this Agreement, OSA, Inc. and TJA
shall commence and thereafter diligently continue to negotiate in good faith the
form of such Customer Agreement.

13.      INDEMNIFICATION.

         13.1 By OSA, Inc.  Subject to the limitations in Section  10.2.3,  OSA,
Inc. shall indemnify, defend and hold harmless TJA, its parent, subsidiaries and
affiliates  (including without  limitation Thermo Instrument and Nicolet),  from
and against any and all losses,  damages,  liabilities and expenses  (including,
without  limitation,  reasonable  attorneys'  fees and  disbursements  and court
costs) incurred by them in connection with third party claims or suits,  whether
based in statute,  contract,  tort,  strict  liability  or breach of warranty or
otherwise,  to the extent  arising,  or alleged by said third party  claimant to
arise,  by reason of (a) the negligence or willful  misconduct of OSA, Inc., its
parent, affiliates, employees, agents, representatives or contractors, (b) false
or misleading statements made by OSA, Inc., its parent,  affiliates,  employees,
agents,  representatives  or  contractors,  to any  persons  including,  but not
limited to, Customers, (c) infringement by the OSA, Inc. Software of any patent,
copyright,  trademark,  trade secret or any other proprietary right of any third
party, (d) use of any Specialized Unit in combination with equipment or software
external  to the  Specialized  Unit  and  not  manufactured  by  TJA  or  Thermo
Instrument,  or any parent,  subsidiary or affiliate of either, which use is not
approved in writing by TJA in an instrument  expressly  referencing this Section
13.1(d) and signed by the President of TJA , (e) TJA's  compliance with designs,
specifications  or  instructions of OSA, Inc., or of any Customer made with OSA,
Inc.'s  approval,  (f)  use  of  any  Specialized  Unit  in  an  application  or
environment  for which the Specialized  Unit design and/or the Specialized  Unit
Specification  applicable thereto is or are inadequate,  unsuitable or otherwise
inappropriate,  (g) use of any Specialized Unit which has been modified pursuant
to the  provisions of Article 6 above or otherwise,  (h) repair,  maintenance or
installation  of, or other tampering with, any Specialized  Unit by anyone other
than TJA or its affiliates,  employees, contractors or agents unless approved by
TJA,  which  approval must be evidenced by an instrument  expressly  referencing
this Section 13.1(h) and signed by the President of TJA, (i) infringement of any
Intellectual  Property rights of any person or entity by OSA,  Inc.'s  Technical
Contributions or Marks or (j) TSI's breach of any


                                      -17-



<PAGE>





representation or warranty under Section 17.16.1 below; provided,  however, that
OSA,  Inc.  shall have no  liability  under this  Section 13.1 to the extent any
third  party  claims or suits are  attributable  to the  negligence  or  willful
misconduct of TJA or its parent, affiliates,  employees, agents, representatives
or contractors.

         13.2 By TJA. Subject to the limitations in Section 10.2.1(b), TJA shall
indemnify,  defend and hold harmless OSA,  Inc.,  its parent,  subsidiaries  and
affiliates  (including  without limitation Top Source and UTG), from and against
any and all  losses,  damages,  liabilities  and  expenses  (including,  without
limitation,  reasonable  attorneys'  fees and  disbursements  and  court  costs)
incurred by them in connection  with third party claims or suits,  whether based
in statute, contract, tort, strict liability or breach of warranty or otherwise,
to the extent  arising,  or alleged by said third party  claimant  to arise,  by
reason  of (a)  the  negligence  or  willful  misconduct  of  TJA,  its  parent,
affiliates,  employees,  agents,  representatives  or contractors,  (b) false or
misleading statements made by TJA, its parent,  affiliates,  employees,  agents,
representatives or contractors,  to any persons  including,  but not limited to,
Customers, (c) infringement by the Instrument Software of any patent, copyright,
trademark,  trade secret or any other  proprietary right of any third party, (d)
use of any Specialized Unit in combination  with equipment or software  external
to the Specialized  Unit and  manufactured by TJA or Thermo  Instrument,  or any
parent,  subsidiary or affiliate of either, or otherwise used with TJA's written
approval,   which  approval  must  be  evidenced  by  an  instrument   expressly
referencing  this Section  13.2(d) and signed by the  President of TJA, (e) OSA,
Inc.'s  compliance  with designs,  specifications  or  instructions  of TJA, (f)
repair,  maintenance,  installation or reinstallation of any Specialized Unit by
TJA  or  its  parent,   affiliates,   employees,   agents,   representatives  or
contractors,  (g) infringement of any Intellectual Property rights of any person
or entity by TJA's  Technical  Contributions  or Marks,  (h) OSA,  Inc.'s or any
Customer's  compliance with written safety or training materials provided by TJA
or (i) Thermo's breach of any  representation  or warranty under Section 17.16.2
below;  provided,  however,  that TJA shall have no liability under this Section
13.2 to the  extent  any third  party  claims or suits are  attributable  to the
negligence  or  willful  misconduct  of OSA,  Inc.  or its  parent,  affiliates,
employees, agents, representatives or contractors.

         13.3     Procedures.  The party seeking indemnification under this
Article 13 ("Indemnified Party") shall provide prompt written
notice of any claim to the party from whom indemnification is
sought hereunder ("Indemnifying Party").  The Indemnifying Party


                                      -18-



<PAGE>





shall  have the right,  at its  option,  to assume the  defense of any claim for
which  indemnification is sought. In the event that the defense of any claim has
been assumed by the  Indemnifying  Party,  the Indemnified  Party shall have the
right to participate in any such  proceeding  with counsel of its own choice and
at its own expense.

         13.4  Terminology.  It is understood  and agreed that any time the term
"contractor(s)" is used in this Agreement,  the same shall be deemed to refer to
and include subcontractor(s) as well.

14.      CONFIDENTIALITY.

         14.1  Proprietary  Information.  All of the  parties to this  Agreement
(i.e., TJA, Thermo  Instrument,  OSA, Inc. and Top Source) agree and acknowledge
that in order to further the performance of this Agreement,  they have disclosed
and will continue to disclose to each other certain information concerning their
respective  Technical   Contributions,   proprietary  inventions,   confidential
know-how and trade secrets  (including  without  limitation  methods or concepts
utilized  therein),  marketing and sales,  pricing (including without limitation
the pricing  information  contained in any  Specialized  Unit Addendum  hereto),
software  (including  without  limitation the Instrument  Software and OSA, Inc.
Software), distributors,  customers, business and other confidential information
(collectively, the "Proprietary Information"). The Proprietary Information shall
remain  the  sole  property  of the  disclosing  party  (the  "Owner"),  and the
receiving  party (the  "Recipient")  shall have no  interest  in, or rights with
respect to, such Proprietary  Information except as set forth in this Agreement.
In  addition,   the  terms  of  this  Agreement  shall  constitute   Proprietary
Information of all parties.

         14.2 Protection. The Recipient agrees to use the same degree of care to
protect the confidentiality of all Proprietary  Information,  designated as such
in writing by the Owner thereof, as a reasonable man would utilize in protecting
his own similar proprietary information, including without limitation agreeing:

                  14.2.1 Except as  specifically  authorized by this  Agreement,
not to permit the disclosure, use, copying, display, loan, publication, transfer
of possession (whether by sale,  exchange,  gift, operation of law or otherwise)
or other dissemination of or access to the Proprietary Information,  in whole or
in part,  to any third  party  without the prior  written  consent of the Owner,
except that such disclosure or access shall be permitted


                                      -19-



<PAGE>





(a)  to an  employee,  agent,  representative,  contractor  or  director  of the
Recipient  requiring access to the Proprietary  Information in the course of his
or her  duties  in  connection  with the  performance  by the  Recipient  of its
obligations   under  this   Agreement   and  who  has  agreed  to  maintain  the
confidentiality of the Proprietary  Information,  (b) with respect to disclosure
only of Proprietary  Information other than the contents of this Agreement, to a
Customer or other third party who has executed a Customer  Agreement or (c) with
respect to  disclosure  of the  contents of this  Agreement  only,  to any party
providing,  or considering providing,  financing or capital to TSI in connection
with any Specialized  Unit developed  hereunder who has agreed,  in writing,  to
maintain the confidentiality of the contents of this Agreement;

                  14.2.2 To notify the Owner  promptly,  and in writing,  of the
circumstances  surrounding  any  suspected  possession,  use or knowledge of the
Proprietary  Information or any part thereof at any location or by any person or
entity other than those whose access thereto is authorized by this Agreement and
take  further  steps as may  reasonably  be requested by the Owner to prevent or
remedy any such  violation.  The Owner  shall be  permitted  to make  reasonable
inquiries  from time to time  concerning  the  Recipient's  compliance  with the
provisions of this Article 14.

         14.3 Exception. Nothing in this Article 14 shall restrict the Recipient
with respect to information or data, whether or not identical or similar to that
contained in the Proprietary  Information,  if such  information or data (a) was
rightfully possessed by the Recipient before it was received from the Owner; (b)
is independently  developed by or for the Recipient  without  derivation from or
reference  to the  Owner's  information  or data;  (c) is or  becomes  public or
available to the general public otherwise than through any act or default of the
Recipient;  (d) becomes available to the Recipient from a source (other than the
Owner) who is not,  to the  Recipient's  knowledge,  bound by a  confidentiality
obligation; or (e) is required by law or stock exchange rule to be disclosed. In
addition,  nothing  in  this  Article  14  shall  restrict  the  Recipient  from
disclosing this Agreement (a) in connection with any legal action to enforce the
terms  hereof  or (b) in  compliance  with  any  valid  subpoena,  provided  the
Recipient  notifies  the Owner  prior to  making  any such  disclosure  and uses
reasonable efforts to obtain a protective  stipulation of  confidentiality  with
respect to the subpoenaed information prior to disclosure of the same.




                                      -20-



<PAGE>





         14.4 Efforts to Maintain Confidentiality. The parties agree to take any
and all reasonable and appropriate  measures to maintain  confidentiality of all
Proprietary  Information in conformance  with the standards set forth in Section
14.2 above, such measures to include,  without  limitation,  written  agreements
with Customers and other users, purchasers,  lessees, licensees and sublicensees
acknowledging  the  parties'   proprietary  rights,   imposing   confidentiality
obligations,  and prohibiting  internal inspection or reverse engineering of any
Specialized  Unit,  the  Instrument  Software  or the  OSA,  Inc.  Software.  No
Specialized  Unit may be  transferred  to any person  without such an agreement.
Said  agreements  shall be in form  acceptable  to counsel for all parties,  and
shall provide that the provisions thereof will survive the expiration or earlier
termination of this Agreement.

         14.5 Obligation to Defend Proprietary Information. Each Owner agrees to
protect  and defend its  Proprietary  Information  against  infringement  to the
extent such Owner, in its sole discretion, considers appropriate. An Owner which
otherwise  would  elect not to protect  and defend its  Proprietary  Information
against  infringement  shall be  obligated  to do so if the other  party pays or
reimburses the Owner for all costs incurred therefor.

         14.6  Injunctive  Relief.  Because the  unauthorized  use,  transfer or
dissemination  of  the  Instrument   Software  or  OSA,  Inc.  Software  or  any
Proprietary  Information  provided  by one  party  to  the  other  may  diminish
substantially the value thereof and of the Specialized Units and may irreparably
harm the offended party, if either party breaches the provisions of this Article
14 or the software licensing provisions of this Agreement, the other party shall
be entitled,  without  limiting its other rights or remedies,  to seek equitable
relief, including, but not limited to, injunctive relief.

15.      TERM AND TERMINATION.

         15.1 Term and Non-Compete.  This Agreement shall be for an initial term
(the "Term")  commencing as of the effective date hereof and continuing  through
and including  December 31, 1997 (the "Term  Expiration  Date"),  unless earlier
terminated in accordance  with the provisions of this Article 15. This Agreement
shall  automatically  terminate  as of the  Term  Expiration  Date  without  the
requirement of notice or any other action on the part of either party hereto.




                                      -21-



<PAGE>





         15.2     Termination.  This Agreement may be terminated as to all
parties prior to the Term Expiration Date:

                  15.2.1 By either  party in the event of a  material  breach by
the other party of any of such other party's  obligations  under this Agreement,
which  breach has not been cured within  sixty (60) days  following  the date on
which the  non-breaching  party has given written notice to the breaching  party
specifying  the nature of the breach  (or, if such breach is of a nature that it
cannot  reasonably be cured within said sixty (60)-day period,  if the breaching
party fails to commence  to cure the same within said sixty  (60)-day  period or
thereafter fails to diligently prosecute such cure to completion);

                  15.2.2 By either party,  effective immediately and without the
requirement  of any  notice,  if the other  party (a) files for or consents to a
general  assignment  for the  benefit  of  creditors,  (b) files a  petition  in
bankruptcy  or  liquidation,  or is  adjudicated  bankrupt or insolvent or takes
similar  actions under the laws of any  jurisdiction  for the general benefit of
creditors of an insolvent or financially  troubled  debtor or (c) is the subject
of an  involuntary  bankruptcy  or  insolvency  proceeding  which is not finally
dismissed within forty-five (45) days;

                  15.2.3 (i)  Notwithstanding  the  provisions  of Section  17.9
below, by TJA, upon not less than thirty (30) days' prior written notice, in the
event of a change in control,  direct or  indirect,  of OSA,  Inc. or Top Source
which has, or in the  reasonable  opinion of TJA could have, a material  adverse
effect on the ability of TSI to perform its  obligations  hereunder or otherwise
on the consummation of the transactions contemplated herein; or

                           (ii) Notwithstanding the provisions of Section 17.9
below,  by OSA, Inc., upon not less than thirty (30) days' prior written notice,
in the  event of a change  in  control,  direct  or  indirect,  of TJA or Thermo
Instrument  which has, or in the  reasonable  opinion of OSA, Inc. could have, a
material  adverse  effect on the  ability of Thermo to perform  its  obligations
hereunder or  otherwise on the  consummation  of the  transactions  contemplated
herein;

                           (iii)  For purposes of this Section 15.2.3,
"control"  shall mean  ownership  of greater  than  fifty  percent  (50%) of the
capital stock or the power to vote or direct the voting of sufficient securities
to elect a majority of the directors;


                                      -22-



<PAGE>






         15.3  Effect of  Expiration  or  Termination.  Upon  expiration  or the
effective date of  termination of this Agreement for any reason,  all rights and
obligations of the parties under this Agreement shall cease, except as follows:

                  15.3.1  In the  event  of the  expiration  of the Term of this
Agreement pursuant to Section 15.1 above, TJA shall complete the manufacture and
shipment of all orders in effect at the time of such  expiration,  and OSA, Inc.
shall  be  obligated  to make  payment  for  the  same in  accordance  with  the
applicable provisions of Article 8 above.

                  15.3.2 At the election of the party initiating  termination in
the case of a termination pursuant to the provisions of Sections 15.2.1,  15.2.2
or 15.2.3 above TJA shall be obligated to complete the  manufacture and shipment
of all (or such portion thereof as is indicated by the electing party under this
Section 15.3.2) orders in effect on the effective date of such termination,  and
OSA, Inc. shall be obligated to make payment for the same in accordance with the
applicable provisions of Article 8 above.

                  15.3.3  OSA,  Inc.  shall,  within  ten (10)  days  after  the
expiration or the effective date of any termination of this  Agreement,  provide
TJA with a list of all Customers for whom the Installation or  Reinstallation of
a Specialized  Unit has been performed by any person or entity other than TJA or
its  designated  subcontractor  or agent.  Such list shall  specify  the date of
Installation or Reinstallation,  as the case may be, and the appropriate contact
with,  and address of, each such  Customer.  TJA may, at its option,  thereafter
communicate directly with such Customers.
                  15.3.4 Solely with respect to Specialized Units purchased from
TJA and paid for by OSA, Inc.  hereunder,  TJA shall  continue,  for a period of
five (5) years following the expiration or the effective date of any termination
of this Agreement, to provide maintenance services for such Specialized Units to
the extent  required by, and in accordance  with,  the provisions of Section 9.2
above.  TJA shall honor  warranty  coverage  extended to Customers by OSA, Inc.,
provided that such coverage  does not exceed the warranty  coverage  provided by
TJA pursuant to the terms of this Agreement.  Solely with respect to Specialized
Units  purchased  from TJA and paid for by OSA,  Inc.  hereunder,  and solely in
connection  with the normal  operation  thereof,  OSA, Inc. and Customers  shall
have, without payment of additional consideration,  the continuing perpetual and
worldwide non-exclusive right and license to use,


                                      -23-



<PAGE>





license and, with respect to OSA, Inc. only, sublicense,  "AS IS, WHERE IS", the
Instrument Software and other Technical  Contributions of TJA and to install and
reinstall such  Specialized  Units with existing or new  Customers,  all without
restriction  except (i) with respect to OSA, Inc., as provided in those Sections
of this  Agreement  which shall  survive,  in accordance  with the provisions of
Section 15.4 below, the expiration or earlier termination of this Agreement, and
(ii) with  respect to any  Customer,  as provided  for the benefit of TJA in the
Customer Agreement.

                  15.3.5 The termination of this Agreement shall not affect OSA,
Inc.'s  obligation  to make  payments  to TJA which have  become due and payable
hereunder  on or before the  effective  date of such  termination,  nor  release
either  party from any  liability to the other party which shall have accrued or
matured at the time such termination becomes effective.

                  15.3.6  On or  before  the  expiration  or  effective  date of
termination  of this  Agreement,  OSA,  Inc.  shall  remove  all TJA Marks  from
Specialized  Units then in OSA, Inc.'s possession and thereafter shall cease all
use of the TJA Marks, including without limitation the use thereof in connection
with the sale, leasing,  licensing,  sublicensing,  distribution or marketing of
Specialized  Units (or related  services);  provided,  however,  that OSA,  Inc.
agrees not to remove or  obscure  any notice of  copyright,  patent,  trademark,
trade  secret or  restricted  or limited  rights  which may be  contained on the
Instrument Software and/or any of TJA's Technical Contributions.

         15.4  Survival.  Notwithstanding  anything  to the  contrary  contained
herein,  the  provisions of Section 3.1,  Section 3.2 (as it relates to the OSA,
Inc. Marks),  Section 4.1, Section 4.2.4,  Section 4.3.2, Section 6, Section 7.7
(first  sentence  only),  Sections  9.1.1 and 9.1.2 (solely with respect to OSAs
purchased from TJA and paid for by OSA, Inc. hereunder),  Section 9.2 (solely to
the extent related to the obligations of TJA under Section 15.3.4),  Article 10,
Article 13, Article 14, Article 15, and, to the extent related to the foregoing,
Articles 1, 16 and 17 (including  without  limitation  Section 17.12 and 17.18),
shall survive any termination or expiration of this Agreement according to their
respective terms. Subject to the limitations of Article 10, an aggrieved party's
right to  pursue  all  legal  remedies  for  breach of  contract  or  otherwise,
including  without  limitation  damages  related  thereto,   shall  survive  any
expiration or earlier termination of this Agreement unimpaired.


                                      -24-



<PAGE>






16.      COMPLIANCE WITH LAWS.

         16.1  Compliance  with Laws.  OSA,  Inc.  and TJA shall comply with all
laws, legislation,  rules,  regulations,  governmental requirements and industry
standards  existing  from time to time with  respect  to the  Specialized  Units
(including without limitation with respect to the sale,  leasing,  licensing and
sublicensing thereof) and performance of their respective obligations hereunder;
provided,  however, that OSA, Inc. shall be solely responsible for ensuring that
the Specialized Units comply with all applicable  governmental  requirements and
industry  standards  imposed by any  foreign  country  prior to any  shipment of
Specialized  Units to any such  country.  In the event  that this  Agreement  is
required to be registered with any foreign  governmental  authority with respect
to Specialized  Units  purchased or  sublicensed  by OSA, Inc.,  OSA, Inc. shall
cause such  registration to be made and shall bear any expense or tax payable in
respect thereof.

         16.2     Customs and Local Taxes.  TJA shall be responsible for
clearing Specialized Units purchased or sublicensed by OSA, Inc.
through customs in the country of destination, provided that OSA,
Inc. shall pay all applicable customs or import duties and all
applicable local taxes.

         16.3  Export.  TJA  shall  not  export  any  Specialized  Unit  to  any
jurisdiction   without  first   obtaining  all  necessary   export  permits  and
clearances,  and in no event shall TJA export any Specialized  Unit in violation
of any  applicable  law or  regulation;  provided that OSA,  Inc.  shall pay all
applicable  permit and clearance fees. Any shipment of Specialized Units by OSA,
Inc. or any Customer  subsequent to the initial  shipment  thereof by TJA (other
than returns to TJA of defective  Specialized Units in accordance with the terms
of this Agreement) shall be the sole  responsibility of OSA, Inc., and OSA, Inc.
shall  comply  with all  import,  export  and  other  laws,  rules,  orders  and
regulations, foreign or domestic, applicable to such re-shipment.

17.      MISCELLANEOUS.

         17.1 Governing  Laws. This Agreement shall be governed by and construed
in  accordance  with  the laws of the  Commonwealth  of  Massachusetts  (without
reference to the conflict of laws  provisions  thereof and  excluding the United
Nations Convention on Contracts for the International Sale of Goods).




                                      -25-



<PAGE>





         17.2 Entire Agreement.  This Agreement constitutes the entire agreement
between the parties with respect to the subject  matter  hereof and shall not be
released, discharged, supplemented, interpreted, amended, varied, or modified in
any manner except by an instrument in writing signed by an authorized officer or
representative  of  each of the  parties  hereto.  The  exhibits  following  the
operative  part of this  Agreement  shall be deemed to be  incorporated  in this
Agreement by this reference and the various other references  contained  herein.
The parties  acknowledge  that they are not entering into this  Agreement on the
basis of any representations not expressly contained herein.

         17.3  Waivers.  No delay or  omission  on the part of any party to this
Agreement in requiring performance by any other party or in exercising any right
hereunder  shall operate as a waiver of any provision  hereof or of any right or
rights hereunder;  and the waiver, omission or delay in requiring performance or
exercising  any right  hereunder on any one occasion shall not be construed as a
bar to or waiver of such performance or right on any future occasion.

         17.4  Severability.  If any provision of this  Agreement  shall for any
reason  be held  illegal  or  unenforceable,  such  provision  shall  be  deemed
severable  from the remaining  provisions of this  Agreement and shall in no way
affect or impair the validity or enforceability  of the remaining  provisions of
this Agreement.

         17.5 Force Majeure.  Notwithstanding anything to the contrary contained
herein,  Thermo  shall  not be  liable  in any  respect  for  any  delay  in the
performance  of any of its  obligations  under this Agreement to the extent such
delay shall have been due to acts of God, acts of  terrorism,  acts of OSA, Inc.
or Top Source, acts of civil or military authority, legal or regulatory changes,
fires,  floods,  epidemics,  quarantine  restrictions,  war, armed  hostilities,
riots, strikes, lockouts,  accidents to machinery, delays in deliveries by TJA's
suppliers,  delays in  transportation  not the  fault of TJA or any other  cause
beyond  the  reasonable  control  of  Thermo.  Notwithstanding  anything  to the
contrary  contained herein, TSI shall not be liable in any respect for any delay
in the  performance of any of its obligations  under this Agreement  (other than
obligations  for the  payment of money) to the extent such delay shall have been
due to acts of God, acts of terrorism, acts of TJA or Thermo Instrument, acts of
civil  or  military  authority,  legal or  regulatory  changes,  fires,  floods,
epidemics,  quarantine  restrictions,  war, armed hostilities,  riots,  strikes,
lockouts or any other cause beyond the reasonable control of TSI.


                                      -26-



<PAGE>






         17.6     Captions.  Article and Section headings are for
descriptive purposes only and shall not control or alter the
meaning of this Agreement.

         17.7  Relationship  of the Parties.  The parties  acknowledge  that the
parties hereto are  independent  contractors and that OSA, Inc. will, on its own
behalf, solicit orders for Specialized Units only as an independent  contractor.
The parties shall not represent themselves as partners, joint-venturers, agents,
employees or general  representatives  of each other for any reason. The parties
acknowledge  that they shall  have no right,  power or  authority  to in any way
obligate  each other to any contract or  obligation  other than the  obligations
contained herein.

         17.8     Notices.  For the purposes of this Agreement, and for all
notices and correspondence hereunder, the addresses of the
respective parties are as follows:

         If to TJA:                          Thermo Jarrell Ash Corporation
                                            27 Forge Parkway
                                            Franklin, MA  02038-3148
                                            Attn.:  President

         with a copy to:                    Thermo Electron Corporation
                                            81 Wyman Street
                                            Waltham, MA  02254 02109
                                            Attn.:  General Counsel

         If to Thermo Instrument:           Thermo Instrument Systems Inc.
                                            1851  Central Drive
                                            Suite 220
                                            Bedford, Texas  76021
                                            Attn.:  President

         with a copy to:                    Thermo Electron Corporation
                                            81 Wyman Street
                                            Waltham, MA  02254
                                            Attn.:  General Counsel

         If to TSI (or one                  On-Site Analysis, Inc.
         or more of OSA,                    3125 Presidential Drive, Suite 130
         Inc., and                          Atlanta, Georgia  30340-3907
         Top Source):                       Attn.:  President





                                      -27-



<PAGE>





         with a copy to:                    Top Source Technologies, Inc.
                                            2000 PGA Boulevard, Suite 3200
                                            Palm Beach Gardens, Florida 
                                             33408-2713
                                            Attn.:   President

                  and:                      Cushing, Morris, Armbruster & Jones
                                            2110 Peachtree Center Cain Tower
                                            229 Peachtree Street, N.E.
                                            Atlanta, Georgia  30303
                                            Attn.:    Kevin R. Armbruster, Esq.

         No change of address shall be binding upon the other party hereto until
written  notice  thereof is received by such party at the address  shown herein.
All notices shall be in English and shall be effective upon receipt if delivered
personally or by courier or sent by facsimile, and three (3) business days after
mailing if sent by United States Mail.

         17.9 Assignment and Corporate Reorganization. None of the parties shall
assign any rights or obligations  under this Agreement without the prior written
consent of the other parties hereto. Notwithstanding the foregoing provisions of
this Section 17.9,  but subject to the provisions of Section  15.2.3,  any party
hereto  ("Assignor")  shall have the right to assign its rights and  obligations
under this  Agreement,  without  the prior  written  consent of any other  party
hereto, (i) to a parent, subsidiary or affiliate of Assignor, (ii) in connection
with a merger,  consolidation  or combination or (iii) in connection with a sale
of substantially all of the assets of Assignor;  provided that any such assignee
shall agree in writing to be bound by all obligations of Assignor hereunder, and
further  provided that,  unless released in writing by the other parties hereto,
Assignor  shall  continue to be bound by all of the terms and conditions of this
Agreement.  Subject to the foregoing,  this Agreement shall inure to the benefit
of and be binding upon any successor or permitted assign of such party.

         17.10             Official Language.  If this Agreement is translated
into another language besides English, the English language version
shall be the official version.

         17.11             Currency.  All prices are in currency of the United
States of America.

         17.12             Guaranty.




                                      -28-



<PAGE>





                  17.12.1 By Top Source. Top Source, as a material inducement to
Thermo to enter into this Agreement,  hereby unconditionally  guarantees, as and
for its own obligation,  the full and prompt  performance by OSA, Inc. of all of
its obligations under this Agreement.  If any such obligations are not performed
when due,  Top Source  will  immediately  perform  them,  without  resort by the
obligee to any other person or party.  TJA and Thermo  Instrument  (or either of
them)  may grant one or more  extensions  to  fulfill  such  obligations  or may
release  or reach a  compromise  with any  person  liable  for such  obligations
without  giving Top Source notice and without  obtaining  Top Source's  consent.
This guaranty shall not be released, in whole or in part, by any action or thing
which might, but for this provision, be deemed a legal or equitable discharge of
a surety or guarantor, or by reason of any waiver,  omission,  action or failure
to act by TJA or Thermo  Instrument  (whether or not Top Source's risk is varied
or increased or its rights or remedies  are affected  thereby),  or by reason of
any further dealings between TSI and TJA or Thermo Instrument.

                  17.12.2 By Thermo Instrument. Thermo Instrument, as a material
inducement  to  TSI  to  enter  into  this  Agreement,   hereby  unconditionally
guarantees  the full and  prompt  performance  by TJA of all of its  obligations
under this Agreement. If any such obligations are not performed when due, Thermo
Instrument will immediately  perform them,  without resort by the obligee to any
other  person or party.  TSI may grant one or more  extensions  to fulfill  such
obligations or may release or reach a compromise with any person liable for such
obligations without giving Thermo Instrument notice and without obtaining Thermo
Instrument's  consent. This guaranty shall not be released, in whole or in part,
by any action or thing which might, but for this provision, be deemed a legal or
equitable  discharge  of a surety or  guarantor,  or by  reason  of any  waiver,
omission,  action or failure to act by TSI  (whether or not Thermo  Instrument's
risk is varied or increased or its rights or remedies are affected thereby),  or
by reason of any further dealings between TJA or Thermo Instrument and TSI.

         17.13  Remedies  Cumulative.  Any and all rights and remedies which any
party may have under this  Agreement,  at law or in equity,  shall be cumulative
and shall not be deemed inconsistent with each other, and any two or more of all
such rights and  remedies may be exercised at the same time insofar as permitted
by law.





                                      -29-



<PAGE>





         17.14  Authority.  The  individuals  executing  this  Agreement  hereby
represent and warrant that they are empowered and duly  authorized to so execute
this Agreement on behalf of the parties they represent.


         17.15 Nicolet. Notwithstanding anything contained in this Agreement, it
is expressly  understood and agreed by all parties hereto that in no event shall
Nicolet be deemed to be a party to this  Agreement or otherwise be subject to or
bound in any way by any of the terms or provisions  contained herein,  including
without limitation the  confidentiality  obligations set forth in Article 14. It
is  further  expressly  understood  and  agreed  by  all  parties  hereto  that,
notwithstanding any provision in this Agreement to the contrary,  TJA and Thermo
Instrument  shall each have the right,  in connection  with the  performance  of
their  respective  obligations  under this Agreement or the  consummation of the
transactions  contemplated  hereby,  to convey,  disclose or  disseminate to any
officer,  employee,  representative  or agent of  Nicolet  (acting in his or her
capacity  as such)  any  Proprietary  Information  of OSA,  Inc.  or Top  Source
(including without  limitation any Intellectual  Property of either such party),
regardless of whether Nicolet, or any such officer, employee,  representative or
agent of Nicolet , shall have theretofore agreed to maintain the confidentiality
of  such   Proprietary   Information,   and  such   conveyance,   disclosure  or
dissemination  shall in no event be  deemed  to  constitute  a breach  by TJA or
Thermo Instrument of any of the provisions of this Agreement,  including without
limitation those contained in or Article 14 above.

         17.16   Representations and Warranties.

                  17.16.1  By OSA, Inc. and Top Source.  OSA, Inc. and Top
Source each warrant and represent that (i) it has full right,
power, capacity and authority to execute, deliver and perform this
Agreement and to consummate the transactions contemplated hereby;
(ii) the execution, delivery and performance of this Agreement, and
the consummation of the transactions contemplated hereby, will not
(A) 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 Articles of Incorporation or Bylaws of OSA,
Inc. or Top Source, as amended, or of any note, bond, mortgage,
indenture, license, agreement or other instrument or obligation to
which OSA, Inc. or Top Source is a party or by which either of


                                      -30-



<PAGE>





them, or any of their respective properties or assets, may be bound or affected,
or (B) result in the violation of any order, writ, injunction,  decree, statute,
rule or regulation  applicable to OSA, Inc. or Top Source,  or their  respective
properties or assets; (iii) this Agreement is enforceable in accordance with its
terms;  and (iv) no consent or approval by, or  notification  to or filing with,
any court,  governmental authority or third party is required in connection with
the execution,  delivery and  performance of this Agreement by OSA, Inc. and Top
Source, or the consummation of the transactions  contemplated hereby. Without in
any way limiting the foregoing,  OSA, Inc.  warrants and represents that it owns
or otherwise has the right to use all  Technical  Contributions  contributed  by
OSA, Inc. (as  referenced in Section 1.11 above) in the  development  of the OSA
and any Specialized Unit hereunder and has obtained all consents,  approvals and
authorizations  required for the use of such Technical  Contributions by TSI and
Thermo in connection with the performance of this Agreement and the consummation
of the transactions  contemplated hereby. Each of the foregoing  representations
and  warranties  shall also be true and  correct as though made on and as of the
date of execution of each Specialized Unit Addendum hereunder.

                  17.16.2  By  TJA  and  Thermo   Instrument.   TJA  and  Thermo
Instrument  each  warrant  and  represent  that  (i) it has full  right,  power,
capacity and  authority to execute,  deliver and perform this  Agreement  and to
consummate the transactions  contemplated  hereby; (ii) the execution,  delivery
and performance of this  Agreement,  and the  consummation  of the  transactions
contemplated  hereby,  will not (A)  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  Articles  of  Incorporation  or Bylaws of TJA or Thermo  Instrument,  as
amended, or of any note, bond, mortgage,  indenture, license, agreement or other
instrument  or  obligation  to which TJA or Thermo  Instrument  is a party or by
which either of them, or any of their  respective  properties or assets,  may be
bound  or  affected,  or  (B)  result  in the  violation  of  any  order,  writ,
injunction,  decree,  statute,  rule or  regulation  applicable to TJA or Thermo
Instrument,  or their respective  properties or assets;  (iii) this Agreement is
enforceable in accordance with its terms; and (iv) no consent or approval by, or
notification to or filing with, any court, governmental authority or third party
is required in connection  with the execution,  delivery and performance of this
Agreement by TJA and Thermo Instrument,  or the consummation of the transactions
contemplated hereby. Without in any way limiting the


                                      -31-



<PAGE>





foregoing,  TJA warrants and represents  that it owns or otherwise has the right
to use all Technical Contributions  contributed by TJA (as referenced in Section
1.11 above) in the development of the OSA and any Specialized Unit hereunder and
has obtained all consents,  approvals and authorizations required for the use of
such  Technical   Contributions  by  Thermo  and  TSI  in  connection  with  the
performance  of  this  Agreement  and  the   consummation  of  the  transactions
contemplated hereby. Each of the foregoing  representations and warranties shall
also be true and  correct as though made on and as of the date of  execution  of
each Specialized Unit Addendum hereunder.

         17.17 Prevailing Party. If any action at law or in equity is brought to
enforce or interpret the provisions of this Agreement,  the prevailing  party in
such action shall be entitled to reimbursement of the reasonable attorneys' fees
and  disbursements  and  court  costs  incurred  by  said  prevailing  party  in
connection with such action.

         17.18  General  Provisions   Regarding   Warranties.   Subject  to  the
provisions of Sections  15.2.3 and 17.9 above,  the warranties  provided to OSA,
Inc. hereunder shall continue to be enforceable by OSA, Inc., in accordance with
the terms of this Agreement, regardless of the transfer by OSA, Inc. of title to
the products to which such warranties relate in the ordinary course of marketing
the  same as  contemplated  by this  Agreement.  Subject  to the  provisions  of
Sections 15.2.3 and 17.9 above,  the warranties  provided to TJA hereunder shall
continue  to be  enforceable  by TJA,  in  accordance  with  the  terms  of this
Agreement,  regardless  of the transfer by TJA of title to the products to which
such  warranties  relate  in the  ordinary  course  of  marketing  the  same  as
contemplated by this Agreement.

         18.      "U" UNIT AGREEMENT.

         Reference is hereby made to that certain Agreement dated as of March 3,
1995 by and between TJA and Thermo  Instrument and OSA, Inc. and Top Source (the
"'U' Unit  Agreement").  It is understood  and agreed that each purchase by OSA,
Inc.  of a  Specialized  Unit  hereunder  shall also be deemed to  constitute  a
purchase by OSA,  Inc. of an OSA for purposes of Sections 15.1 and 15.2.6 of the
"U" Unit Agreement.  Notwithstanding  anything to the contrary  contained in the
"U" Unit Agreement,  including without limitation the provisions of Sections 5.2
and 15.1 thereof,  it is further  understood and agreed that the  performance by
either  party of its  obligations  under this  Agreement  will not  constitute a
default by


                                      -32-



<PAGE>





such  party  under  the "U" Unit  Agreement.  The "U" Unit  Agreement  is hereby
ratified and  confirmed in its  entirety,  and,  except to the extent  expressly
provided  in this  Article  18,  nothing  contained  herein  shall be  deemed to
constitute an amendment to or modification of the "U" Unit Agreement.

         IN  WITNESS  WHEREOF,  the  parties  hereto  have  duly  executed  this
Agreement under seal as of the day and year first above written.


         TJA:

         THERMO JARRELL ASH CORPORATION

         By:  /s/ Earl Lewis
         Title:  Sr. Vice President

         Witness/
         Attest:
         Title:

                                [CORPORATE SEAL]



         THERMO INSTRUMENT:

         THERMO INSTRUMENT SYSTEMS INC.

         By:  /s/ Earl Lewis
         Title:  Sr. Vice President

         Witness/
         Attest:
         Title:

                                [CORPORATE SEAL]




[Signatures Continued on Next Page]






                                      -33-



<PAGE>






         OSA, INC.:

         ON-SITE ANALYSIS, INC.

         By:  /s/ Stuart Landow 12/28/95
         Title:   CEO

         Witness/
         Attest:  /s/ Jane M. Ott
         Title:  Corporate Administrator

                                [CORPORATE SEAL]



         TOP SOURCE:

         TOP SOURCE TECHNOLOGIES, INC.


         By:  /s/ Stuart Landow 12/28/95
         Title:   CEO

         Witness/
         Attest:  /s/ Jane M. Ott
         Title:  Corporate Administrator

                                [CORPORATE SEAL]














AA953250027



                                      -34-



<PAGE>




LIST OF EXHIBITS



Exhibit A         "U" Specification

Exhibit B         Site Survey Report

Exhibit C         Customer Site Specifications for
Installation




AA953250027




                                      -35-



<PAGE>