Filer:  Thermo Electron Corporation
                                Subject Company:  Thermo Instrument Systems Inc.
                                  Subject Company Exchange Act File No.:  1-9786
                                          Registration Statement No.:  333-35478

PRESS RELEASE:

Investor Contact: 781-622-1111
Media Contact: 781-622-1252

               Thermo Electron Completes Thermo Instrument and
                           Thermedics Exchange Offers

WALTHAM, Mass., June 30, 2000 - Thermo Electron Corporation (NYSE-TMO) announced
today  that  it has  successfully  completed  its  exchange  offers  for  Thermo
Instrument  Systems Inc. and Thermedics  Inc.  common stock.  Thermo  Instrument
shareholders  received  0.85  shares of Thermo  Electron  common  stock for each
Thermo  Instrument  share, and Thermedics  shareholders  received 0.45 shares of
Thermo Electron common stock for each Thermedics share, tendered in the exchange
offers.  The  Securities  and Exchange  Commission  declared  Thermo  Electron's
registration statement for each of these exchange offers effective on Wednesday,
June 28, 2000.

     According to reports from the depositaries for the exchange offers,  Thermo
Electron  acquired  approximately 13 million shares of Thermo  Instrument common
stock and  approximately  8.4 million  shares of Thermedics  common stock in the
exchange offers. These shares represent  approximately 10.1 percent of the total
number of Thermo Instrument shares  outstanding (98.6 percent when combined with
shares held by Thermo Electron) and approximately 20 percent of the total number
of Thermedics shares outstanding (95.5 percent when combined with shares held by
Thermo Electron).

     Thermo  Electron  intends to acquire the remaining  Thermo  Instrument  and
Thermedics shares later today through short-form mergers with both subsidiaries.
Once Thermo Electron completes the short-form  mergers,  Thermo Instrument's and
Thermedics'  shares  will no longer be listed on the  American  Stock  Exchange.
Shareholders who did not tender their shares in the exchange offers will receive
the same per-share consideration in the short-form mergers.

     Thermo  Electron's  transfer  agent,  EquiServe  Trust Company,  N.A., will
forward to Thermo  Instrument  and  Thermedics  shareholders  who did not tender
their shares in the  exchange  offers  detailed  instructions  regarding  how to
surrender their stock  certificates in order to receive Thermo Electron  shares.
Shareholders  should not submit their stock  certificates  to the transfer agent
until they have received these materials.

     Options to purchase Thermo  Instrument and Thermedics common stock that are
outstanding  at the time of the mergers  will be assumed by Thermo  Electron and
converted into options to purchase  Thermo  Electron  common stock.  Obligations
outstanding at the time of the mergers under Thermo Instrument's and Thermedics'
convertible  debentures will be assumed by Thermo Electron, and these debentures
will be convertible into Thermo Electron shares.


     Thermo  Electron  Corporation  is a  leading  provider  of  analytical  and
monitoring instruments used in a broad range of applications, from life sciences
research to  telecommunications  to food and beverage  production.  In addition,
Thermo  Electron  serves  the  healthcare  market  through a family  of  medical
companies,  and is a major  producer of paper  recycling  systems  and  provides
fiber-recovery  products.  As  announced  on January 31,  2000,  the company has
initiated  a major  reorganization  that would  transform  it into one  publicly
traded entity focused on its core instruments  business.  The company's  medical
products and paper recycling  businesses will be spun off as dividends to Thermo
Electron  shareholders.  More  information  is  available  on  the  Internet  at
http://www.thermo.com.

Other Important Information:

We urge investors and security holders to read the following documents when they
become available,  regarding the exchange offer and the merger described in this
announcement, because they contain important information:

- -  Thermo Electron's preliminary  prospectus,  any prospectus supplement,  final
   prospectus,  and  other  materials  relating  to the  Thermo  Instrument  and
   Thermedics exchange offers.

- -  Thermo  Electron's  registration  statements on Form S-4 and Schedules TO, as
   amended, which relate to the Thermo Instrument and Thermedics exchange offers
   and contain or incorporate by reference the documents  listed above and other
   information.

- -  Thermo Instrument's and Thermedics' solicitation/recommendation statement
   on Schedule 14D-9.

These  documents and  amendments to these  documents  have been or will be filed
with the SEC. When these and other documents are filed with the SEC, they may be
obtained for free at the SEC's Web site at www.sec.gov.  You may also obtain for
free each of these documents,  when available, from us. You can call us at (781)
622-1111 or write to us at:


Investor Relations Department
Thermo Electron Corporation
81 Wyman Street, P.O. Box 9046
Waltham, MA  02454-9046

The following constitutes a "Safe Harbor" statement under the Private Securities
Litigation  Reform Act of 1995:  This  press  release  contains  forward-looking
statements that involve a number of risks and  uncertainties.  Important factors
that could cause actual  results to differ  materially  from those  indicated by
such  forward-looking  statements are set forth under the heading "Risk Factors"
in the company's Amendment No. 2 to Registration Statement on Form S-4 [Reg. No.
333-35478]  filed with the Securities and Exchange  Commission on June 27, 2000.
These include  risks and  uncertainties  relating to: the  company's  ability to
complete its corporate reorganization, the need for a favorable Internal Revenue
Service ruling regarding planned spin-offs of certain subsidiaries, divestitures
planned as part of the reorganization, integration of the instrument businesses,
issuance  of   significant   amounts  of  additional   shares  as  part  of  the
reorganization,  liquidity and prospective performance of the subsidiaries to be
spun off,  guarantees of obligations of the  subsidiaries  to be spun off, stock
price volatility,  goodwill acquired by the company, internal growth, the effect
of  exchange  rate  fluctuations  on  the  company's  significant  international
operations,   the  need  to  develop  new  products  and  adapt  to  significant
technological  change,  changes in governmental  regulations,  and dependence of
demand on capital spending and government funding policies.


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