THIS PAPER DOCUMENT IS BEING SUBMITTED PURSUANT 
                TO RULE 902(g) OF REGULATION S-T

               SECURITIES AND EXCHANGE COMMISSION
                     Washington, D.C.  20549
                                
                                                
                          SCHEDULE 13D
                       (Amendment No. 29)
                                
                                                
            Under the Securities Exchange Act of 1934
                                 
                       IDEX CORPORATION                
                        (Name of Issuer)
                                
                        
             Common Stock Par Value $0.01 Per Share     
                (Title of Class and Securities) 
                                
                                                
                           45167R104                  
              (CUSIP Number of Class of Securities)
                                                
                                                
                                                
              James E. McKee, Gabelli Funds, Inc.,
 One Corporate Center, Rye, New York 10580-1434, (914) 921-5067
    (Name, Address and Telephone Number of Person Authorized
             to Receive Notices and Communications)
                                
                                                
                       May 13, 1996                       
     (Date of Event Which Requires Filing of this Statement)
                                

If the filing person has previously filed a statement on Schedule
13G to report the acquisition which is the subject of this State-
ment because of Rule 13D-1(b)(3) or (4), check the following box:
                                                        ____     
                                                       /___/ 


Check the following box if a fee is being paid with this Statement:
                                                       ____
                                                      /   /

_________________________________________________________________

CUSIP No. 45167R104                                        13D
_________________________________________________________________
(1)  NAMES OF REPORTING PERSONS 
      S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
      Gabelli Funds, Inc.            I.D. No. 13-3056041
_________________________________________________________________
(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                                       ____
                                                  (a) /___/
                                                       ____
                                                  (b) /___/
_________________________________________________________________
(3)  SEC USE ONLY
_________________________________________________________________
(4)  SOURCE OF FUNDS*
      00: Funds of investment company clients
_________________________________________________________________
(5)  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
     REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)          _____
                                                     /   /
_________________________________________________________________
(6)  CITIZENSHIP OR PLACE OF ORGANIZATION
      New York
_________________________________________________________________ 
                                        : (7) SOLE VOTING POWER
                                        :     742,200 (Item 5)
                                        :________________________
                                        : (8) SHARED VOTING POWER
 NUMBER OF SHARES BENEFICIALLY          :     None    (Item 5) 
 OWNED BY EACH REPORTING                :________________________
 PERSON WITH                            : (9) SOLE DISPOSITIVE 
                                        :     POWER
                                        :     742,200 (Item 5)
                                        :________________________
                                        :(10) SHARED DISPOSITIVE 
                                        :     POWER
                                        :     None    (Item 5)  
_________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
      742,200   (Item 5)
_________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11
     EXCLUDES CERTAIN SHARES*                         _____
                                                     /  x /
_________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
      3.86%
_________________________________________________________________
(14) TYPE OF REPORTING PERSON*
      HC, IA, CO
_________________________________________________________________
              *SEE INSTRUCTIONS BEFORE FILLING OUT!  
________________________________________________________________

CUSIP No. 45167R104                                        13D
_________________________________________________________________
(1)  NAMES OF REPORTING PERSONS 
      S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
      GAMCO Investors, Inc.              I.D. No. 13-2951242
_________________________________________________________________
(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                                       ____
                                                  (a) /___/
                                                       ____
                                                  (b) /___/
_________________________________________________________________
(3)  SEC USE ONLY
_________________________________________________________________
(4)  SOURCE OF FUNDS*
      OO:  Funds of investment advisory clients
_________________________________________________________________
(5)  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
     REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)         ____
                                                     /x___/
_________________________________________________________________
(6)  CITIZENSHIP OR PLACE OF ORGANIZATION
      New York
_________________________________________________________________ 
                                        : (7) SOLE VOTING POWER
                                        :     1,361,690 (Item 5)
                                        :________________________
                                        : (8) SHARED VOTING POWER
 NUMBER OF SHARES BENEFICIALLY          :     None 
 OWNED BY EACH REPORTING                :________________________ 
 PERSON WITH                            : (9) SOLE DISPOSITIVE 
                                        :     POWER
                                        :     1,422,440 (Item 5)
                                        :________________________ 
                                        :(10) SHARED DISPOSITIVE 
                                        :     POWER
                                        :     None  
_________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
      1,422,440 (Item 5)
_________________________________________________________________

(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11
     EXCLUDES CERTAIN SHARES*                        ____
                                                     /___/
_________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
      7.42%      
________________________________________________________
(14) TYPE OF REPORTING PERSON*
      IA, CO
_________________________________________________________________
              *SEE INSTRUCTIONS BEFORE FILLING OUT!   
_________________________________________________________________

CUSIP No. 45167R104                                        13D
_________________________________________________________________
(1)  NAMES OF REPORTING PERSONS 
      S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
      Gabelli Asset Management Company International Advisory     
      Services Ltd. 
_________________________________________________________________
(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                                       ____
                                                  (a) /___/
                                                       ____
                                                  (b) /___/
_________________________________________________________________
(3)  SEC USE ONLY
_________________________________________________________________
(4)  SOURCE OF FUNDS*
      00-Funds of clients
_________________________________________________________________
(5)  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
     REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)          ____
                                                     /___/
_________________________________________________________________
(6)  CITIZENSHIP OR PLACE OF ORGANIZATION
      Bermuda                     
_________________________________________________________________ 
                                        : (7) SOLE VOTING POWER
                                        :     1,000 (Item 5)
                                        :________________________
                                        : (8) SHARED VOTING POWER
 NUMBER OF SHARES BENEFICIALLY          :     None  
 OWNED BY EACH REPORTING                :________________________ 
 PERSON WITH                            : (9) SOLE DISPOSITIVE 
                                        :     POWER
                                        :     1,000 (Item 5)
                                        :________________________ 
                                        :(10) SHARED DISPOSITIVE 
                                        :     POWER
                                        :     None  
_________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
      1,000 (Item 5)
_________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11
     EXCLUDES CERTAIN SHARES*                         ____
                                                     /___/
_________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
      0.01%
_________________________________________________________________
(14) TYPE OF REPORTING PERSON*
      CO
_________________________________________________________________

_________________________________________________________________

CUSIP No. 45167R104                                        13D
_________________________________________________________________
(1)  NAMES OF REPORTING PERSONS 
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
     Mario J. Gabelli                  I.D. No. ###-##-####
_________________________________________________________________ 
(2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
                                                       ____
                                                  (a) /___/
                                                       ____
                                                  (b) /___/
_________________________________________________________________
(3)  SEC USE ONLY
_________________________________________________________________
(4)  SOURCE OF FUNDS*
     None
_________________________________________________________________
(5)  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS
     REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)          ____
                                                     / x /
_________________________________________________________________
(6)  CITIZENSHIP OR PLACE OF ORGANIZATION
      USA 
_________________________________________________________________ 
                                        : (7) SOLE VOTING POWER
                                        :     None (Item 5)
                                        :________________________
                                        : (8) SHARED VOTING POWER
 NUMBER OF SHARES BENEFICIALLY          :     None  
 OWNED BY EACH REPORTING                :________________________ 
 PERSON WITH                            : (9) SOLE DISPOSITIVE 
                                        :     POWER
                                        :     None (Item 5)
                                        :________________________ 
                                        :(10) SHARED DISPOSITIVE 
                                        :     POWER
                                        :     None  
_________________________________________________________________
(11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
     None (Item 5)
_________________________________________________________________
(12) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11
     EXCLUDES CERTAIN SHARES*                         _____
                                                     /  x /
_________________________________________________________________
(13) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11
      0.00%
_________________________________________________________________
(14) TYPE OF REPORTING PERSON*
      IN
_________________________________________________________________

              *SEE INSTRUCTIONS BEFORE FILLING OUT!
Item 1.Security and Issuer

          The class of equity security to which this statement on

Form Schedule 13D relates is the Common Stock, par value $0.01 

per share ("Securities"), of IDEX Corporation (the "Issuer), a 

Delaware corporation, with principal offices located at 630 

Dundee Road, Suite 400, Northbrook, Illinois, 60062.

          This Amendment No. 29 to Schedule 13D on IDEX 
Corporation (the "Issuer") is being filed on behalf of the
undersigned to amend the Schedule 13D, as amended (the "Schedule
13D") which was originally filed on June 16, 1989.  

Item 2.   Identity and Background
          This statement is being filed by Mario J. Gabelli ("Mr.
Gabelli") and various entities which he directly or indirectly
controls or for which he acts as chief investment officer.  These
entities, except for Lynch Corporation ("Lynch"), Spinnaker
Industries, Incorporated ("Spinnaker"), Western New Mexico
Telephone Company ("Western New Mexico"), Entoleter, Inc.
("Entoleter"),  Lynch Telecommunications Corporation ("Lynch
Telecom"), Lynch Telephone Corporation ("Lynch Telephone") and
Inter-Community Telephone Company ("Inter-Community")
(collectively, "Lynch and its affiliates"), engage in various
aspects of the securities business, primarily as investment
adviser to various institutional and individual clients, includ-
ing registered investment companies and pension plans, as
broker/dealer and as general partner of various private invest-
ment partnerships.  Certain of these entities may also make
investments for their own accounts. 
          The foregoing persons in the aggregate often own
beneficially more than 5% of a class of equity securities of a
particular issuer.  Although several of the foregoing persons are
treated as institutional investors for purposes of reporting
their beneficial ownership on the short-form Schedule 13G, the
holdings of those who do not qualify as institutional investors
may exceed the 1% threshold presented for filing on Schedule 13D
or implementation of their investment philosophy may from time to
time require action which could be viewed as not completely
passive.  In order to avoid any question as to whether their
beneficial ownership is being reported on the proper form and in
order to provide greater investment flexibility and administra-
tive uniformity, these persons have decided to file their benefi-
cial ownership reports on the more detailed Schedule 13D form
rather than on the short-form Schedule 13G and thereby to provide
more expansive disclosure than may be necessary. 
          (a), (b) and (c) - This statement is being filed by one
or more of the following persons: Gabelli Funds, Inc. ("GFI"),
GAMCO Investors, Inc. ("GAMCO"), Gabelli Securities, Inc.
("GSI"), Gabelli & Company, Inc. ("Gabelli & Company"), Gabelli
Performance Partnership L.P. ("GPP"), GLI, Inc. ("GLI"), Gabelli
Associates Fund ("Gabelli Associates"), Gabelli Associates
Limited ("GAL"), Gabelli & Company, Inc. Profit Sharing Plan (the
"Plan"), Gabelli International Limited ("GIL"), Gabelli Interna-
tional II Limited ("GIL II"), Gabelli International Gold Fund
Limited ("GIGFL"), ALCE Partners, L.P. ("ALCE"), Gabelli
Multimedia Partners, L.P. ("Multimedia Partners"), Gabelli Asset
Management Company International Advisory Services Ltd.
("GIASL"), Mr. Gabelli, Lynch, Spinnaker, Western New Mexico,
Entoleter, Lynch Telecom, Lynch Telephone and Inter-Community.
Those of the foregoing persons signing this Schedule 13D are
hereafter referred to as the "Reporting Persons". 
          GAMCO, a majority owned subsidiary of GFI, is an
investment adviser registered under the Investment Advisers Act
of 1940, as amended ("Advisers Act").  GAMCO is an investment
manager providing discretionary managed account services in the
equity area for employee benefit plans, private investors,
endowments and foundations. 
          Gabelli & Company, a wholly-owned subsidiary of GSI, is
a broker-dealer registered under the Securities Exchange Act of
1934, as amended ("l934 Act"), which as a part of its business
regularly purchases and sells securities for its own account.  
          GLI, a wholly-owned subsidiary of GSI, is a general
partner of G&R Partners, a Delaware partnership ("G&R"), which,
in turn, is the general partner of Gabelli-Rosenthal & Partners,
L.P., a Delaware limited partnership ("G-R"), whose primary busi-
ness purpose is to do friendly leveraged buyouts.  At the present
time, G-R's sole business purpose is to monitor its existing
portfolio investments.
          Gabelli Associates is a New York limited partnership
whose primary business purpose is risk arbitrage investments. 
GSI and Mr. Gabelli are the general partners of Gabelli As-
sociates. 
          GAL is a corporation whose primary business purpose is
risk arbitrage investments.  Shares of GAL's Common Stock will be
offered to persons who are neither citizens nor residents of the
United States and may be offered to a limited number of U.S.
investors.  GSI is the investment manager of GAL.
          GSI, a majority-owned subsidiary of GFI, is a Delaware
corporation which as a part of its business regularly purchases
and sells securities for its own account.  It is the immediate
parent of Gabelli & Company.  
          GFI is the ultimate parent company for a variety of
companies engaged in the securities business, each of which is
named above.  In addition, GFI is an investment adviser
registered under the Advisers Act.  GFI is an investment adviser
which presently provides discretionary managed account services
for The Gabelli Equity Trust Inc., The Gabelli Asset Fund, The
Gabelli Growth Fund, The Gabelli Convertible Securities Fund,
Inc., The Gabelli Value Fund Inc., The Gabelli Small Cap Growth
Fund, The Gabelli Equity Income Fund, The Gabelli ABC Fund, The
Gabelli Global Telecommunications Fund, Gabelli Gold Fund, Inc.,
The Gabelli Global Multimedia Trust Inc., The Gabelli Global
Convertible Securities Fund, Gabelli Capital Asset Fund, Gabelli
International Growth Fund, Inc. and The Gabelli Global
Interactive Couch Potato Fund (collectively, the "Funds"), which
are registered investment companies.
          The Plan, a qualified employee profit sharing plan,
covers substantially all employees of GFI and its affiliates. 
          GPP, a Delaware limited partnership, is a limited
partnership whose primary business purpose is investing in
securities.  Mr. Gabelli is the general partner and chief invest-
ment officer of GPP. 
          GIL is a corporation whose primary business purpose is
investing in a portfolio of equity securities and securities
convertible into, or exchangeable for, equity securities in order
to achieve its investment objective of significant long-term
growth of capital.  Shares of GIL's common stock are offered to
persons who are neither citizens nor residents of the United
States and may be offered to a limited number of U.S. investors. 
The investments of GIL are managed by Mr. Gabelli who is also a
director and Chairman of the Board of Directors of GIL.
          GIL II is a corporation whose business purpose is
investing primarily in a portfolio of equity securities and
securities convertible into, or exchangeable for, equity securit-
ies in order to achieve its investment objective of significant
long-term growth of capital.  Shares of GIL II's common stock are
offered to persons who are neither citizens nor residents of the
United States and may be offered to a limited number of U.S.
investors.  The investments of GIL II are managed by Mr. Gabelli
who is also a director and Chairman of the Board of Directors of
GIL II.
       ALCE is a Delaware investment limited partnership that
seeks long-term capital appreciation primarily through
investments in public and private equity securities.  GSI is a
general partner of ALCE.
       Multimedia Partners is a Delaware investment limited
partnership whose objective is to provide long-term capital
appreciation by investing primarily in public and private
multimedia communications companies.  GSI is a general partner of
Multimedia Partners.
       GIASL is a corporation whose primary business purpose is
to provide advisory services to offshore funds.
       Lynch, an Indiana corporation, is a diversified public
company traded on the American Stock Exchange.  Its subsidiaries
are engaged in communications, services, and manufactured pro-
ducts.  Spinnaker, a Delaware subsidiary of Lynch, is also a
public company and its stock is traded through the NASDAQ System. 
Spinnaker is a diversified manufacturing firm with major
subsidiaries in specialty adhesive-backed materials business. 
Another of Lynch's subsidiaries, Western New Mexico, provides
telephone services in a service area in Southwestern New Mexico. 
Inter-Community, which is also a subsidiary of Lynch, provides
local telephone services in an area 40 miles west of Fargo, North
Dakota.   Lynch and Spinnaker actively pursue new business ven-
tures and acquisitions.  Lynch and its affiliates make invest-
ments in marketable securities to preserve capital and maintain
liquidity for financing their business activities and
acquisitions (not in the case of Western New Mexico) and are not
engaged in the business of investing, reinvesting, or trading in
securities.  Mr. Gabelli is Chairman of Lynch and owns
beneficially 25.9% of the shares of common stock of Lynch. 
          Mr. Gabelli is the majority stockholder and Chairman of
the Board of Directors and Chief Executive Officer of GFI and the
Chief Investment Officer for each of the Reporting Persons.  GFI,
in turn, is the majority stockholder of GAMCO.  GFI is also the
majority stockholder of GSI.  Gabelli & Company is a wholly-owned
subsidiary of GSI.  GLI is a wholly-owned subsidiary of GSI.
          The Reporting Persons do not admit that they constitute
a group. 
          GFI, GAMCO, Gabelli & Company and GLI are New York
corporations and GSI is a Delaware corporation, each having its
principal business office at One Corporate Center, Rye, New York
10580-1434. GPP is a Delaware limited partnership having its
principal business office at 8 Sound Shore Drive, Greenwich,
Connecticut 06830.  Gabelli Associates is a New York limited
partnership having its principal business office at One Corporate
Center, Rye, New York 10580-1434. GAL and GIL are corporations
organized under the laws of the British Virgin Islands having
their principal business office at c/o MeesPierson (Cayman)
Limited, British American Centre, Dr. Roy's Drive-Phase 3, George
Town, Grand Cayman, British West Indies.  GIL II is a corporation
organized under the laws of the British Virgin Islands having
their principal business office at c/o Coutts & Company (Cayman)
Limited, West Bay Road, Grand Cayman, British West Indies.  GIASL
is a Bermuda corporation with its principal business office at
c/o Appleby, Spurling & Kempe, Cedar House, 41 Cedar Avenue,
Hamilton HM12, Bermuda.  Lynch is an Indiana corporation having
its principal business office at 8 Sound Shore Drive, Greenwich,
CT 06830.  Spinnaker is a Delaware corporation having its
principal business office at 251 Welton Street, Hamden, CT 06511.

          For information required by instruction C to Schedule
13D with respect to the executive officers and directors of the
foregoing entities and other related persons (collectively,
"Covered Persons"), reference is made to Schedule I annexed
hereto and incorporated herein by reference. 
          (d) and (e) -  On December 8, 1994, the SEC instituted
and simultaneously accepted offers for the settlement of an
administrative proceeding against Gabelli & Company and GAMCO. 
The order instituting the proceeding included a finding, which
Gabelli & Company and GAMCO neither admitted nor denied, that
they failed to implement and maintain policies and procedures
reasonably designed to prevent the misuse of material, nonpublic
information by not sepecifically addressing the special
circumstances that arose from their affiliation with Lynch
Corporation, a public company.  To resolve this matter, Gabelli &
Company and GAMCO agreed to cease and desist from violating
Section 15(f) of the 1934 Act and Section 204A of the Advisers
Act, respectively.  They further agreed to each pay a civil
penalty in the amount of $50,000, and to retain, and adopt the
recommendations of, an independant consultant regarding their
Section 15(f) and Section 204A policies and procedures.  
          On December 13, 1991, the Virginia State Corporation
Commission entered an order of settlement in final disposition of
matters arising from an allegation that GAMCO had transacted
business in Virginia as an investment adviser without having been
registered as such under Virginia Code Section 13.1-504A or an
exemption therefrom.  GAMCO consented to the entry of the order
without admitting or denying the allegation and without a
hearing.  The terms of the order provide that GAMCO would pay a
fine and costs totalling fifty-five thousand dollars and would
not transact business in Virginia as an investment adviser unless
it was registered as such under section 13.1-504A or was exempt
from registration.  
     (f) - Reference is made to Schedule I hereto. 

Item 3.   Source and Amount of Funds or Other Consideration
          All Reporting Persons used an aggregate of
approximately $22,799,858 to purchase Securitites beneficially
owned by them as reported in Item 5 below.  GAMCO and GFI used
approximately $14,975,448 and $8,334,906, respectively, of funds
that were provided throught the accounts of certain of their
investment advisory clients (and, in the case of some such
accounts at GAMCO, may be through the borrowings from margin
accounts) in order to purchase the Securities for such clients. 
GIASL used approximately $37,050 of funds from a client account
to purchase the Securities reported by it.

Item 4.   Purpose of Transaction
          Each of the Reporting Persons, with the exceptions of
Lynch and its affiliates, has purchased and holds the Securities
reported by it for investment for one or more accounts over which
it has shared, sole, or both investment and/or voting power, for
its own account, or both. 
          The Reporting Persons, with the exceptions of Lynch and
its affiliates, are engaged in the business of securities
analysis and investment and pursue an investment philosophy of
identifying undervalued situations.  In pursuing this investment
philosophy, the Reporting Persons analyze the operations, capital
structure and markets of companies in which they invest,
including the Issuer, on a continuous basis through analysis of
documentation and discussions with knowledgeable industry and
market observers and with representatives of such companies
(often at the invitation of management). The Reporting Persons do
not believe they possess material inside information concerning
the Issuer.  As a result of these analytical activities one or
more of the Reporting Persons may issue analysts reports,
participate in interviews or hold discussions with third parties
or with management in which the Reporting Person may suggest or
take a position with respect to potential changes in the opera-
tions, management or capital structure of such companies as a
means of enhancing shareholder values. Such suggestions or
positions may relate to one or more of the transactions specified
in clauses (a) through (j) of Item 4 of the Schedule 13D form,
including, without limitation, such matters as disposing of one
or more businesses, selling the company or acquiring another
company or business, changing operating or marketing strategies,
adopting or not adopting, certain types of anti-takeover measures
and restructuring the company's capitalization or dividend poli-
cy. 
          Each of the Reporting Persons intends to adhere to the
foregoing investment philosophy with respect to the Issuer.  How-
ever, none of the Reporting Persons intends to seek control of
the Issuer or participate in the management of the Issuer, and
any Reporting Person that is registered as an investment company
under the l940 Act will participate in such a transaction only
following receipt of an exemption from the SEC under Rule l7D-l
under the l940 Act, if required, and in accordance with other
applicable law. In pursuing this investment philosophy, each
Reporting Person will continuously assess the Issuer's business,
financial condition, results of operations and prospects, general
economic conditions, the securities markets in general and those
for the Issuer's securities in particular, other developments and
other investment opportunities, as well as the investment
objectives and diversification requirements of its shareholders
or clients and its fiduciary duties to such shareholders or
clients.  Depending on such assessments, one or more of the
Reporting Persons may acquire additional Securities or may
determine to sell or otherwise dispose of all or some of its
holdings of Securities.  Although the Reporting Persons share the
same basic investment philosophy and although portfolio decisions
are made by or under the supervision of Mr. Gabelli, the
investment objectives and diversification requirements of various
clients differ from those of other clients so that one or more
Reporting Persons may be acquiring Securities while others are
disposing of Securities.
          With respect to voting of the Securities, the Reporting
Persons have adopted general voting policies relating to voting
on specified issues affecting corporate governance and sharehold-
er values.  Under these policies, the Reporting Persons generally
vote all securities over which they have voting power in favor of
cumulative voting, financially reasonable golden parachutes, one
share one vote, management cash incentives and pre-emptive rights
and against greenmail, poison pills, supermajority voting, blank
check preferred stock and super-dilutive stock options. 
Exceptions may be made when management otherwise demonstrates
superior sensitivity to the needs of shareholders.  In the event
that the aggregate voting position of all joint filers shall
exceed 25% of the total voting position of the issuer then the
proxy voting committees of each of the Funds shall vote their
Fund's shares independently.
          Each of the Covered Persons who is not a Reporting
Person has purchased the Securities reported herein as benefi-
cially owned by him for investment for his own account or that of
one or more members of his immediate family. Each such person may
acquire additional Securities or dispose of some or all of the
Securities reported herein with respect to him. 
          Other than as described above, none of the Reporting
Persons and none of the Covered Persons who is not a Reporting
Person has any present plans or proposals which relate to or
would result in any transaction, change or event specified in
clauses (a) through (j) of Item 4 of the Schedule 13D.           

Item 5.   Interest In Securities Of The Issuer
          (a)  The aggregate number and percentage of Securities
to which this Schedule 13D relates is 2,165,640 shares, repre-
senting 11.29% of the 19,181,604 shares outstanding as reported
in the most recently filed Form 10-Q for the quarter ended March
31, 1996.  The Reporting Persons beneficially own those
Securities as follows: 















                         Shares of           % of
                         Common              Class of
Name                     Stock               Common  

GAMCO 
  As Principal                  0                0.00%
  As Agent              1,361,690                7.42%

GFI
  As Principal                  0                0.00%
  As Agent                742,200                3.86%

GIASL                       1,000                0.01%

Mr. Gabelli                     0                0.00% 

           Mr. Gabelli is deemed to have beneficial ownership of
the Securities owned beneficially by each of the foregoing
persons and GFI is deemed to have beneficial ownership of the
securities owned beneficially by each of the foregoing persons
other than Mr. Gabelli. 
          (b) Each of the Reporting Persons and Covered Persons has
the sole power to vote or direct the vote and sole power to dispose
or to direct the disposition of the Securities reported for it,
either for its own benefit or for the benefit of its investment
clients or its partners, as the case may be, except that GAMCO
Investors, Inc. does not have authority to vote 60,750 of the
reported shares, and except that GFI has sole dispositive and
voting power with respect to the 742,200 shares of the Issuer held
by the the Funds, so long as the aggregate voting interest of all
joint filers does not exceed 25% of their total voting interest in
the Issuer and in that event, the Proxy Voting Committee of each of
the Funds shall respectively vote that Fund's shares, and except
that, at any time, the Proxy Voting Committee of each such Fund may
take and exercise in its sole discretion the entire voting power
with respect to the shares held by such Fund under special
circumstances such as regulatory considerations, and except that
the power of Mr. Gabelli and GFI is indirect with respect to
Securities beneficially owned directly by other Reporting Persons. 
          (c) Information with respect to all transactions in the
Securities which were effected during the past sixty days by each
of the Reporting Persons and Covered Persons is set forth on
Schedule II annexed hereto and incorporated herein by reference. 

Item 6.   Contracts, Arrangements, Understandings or 
          Relationships with Respect to Securities of the Issuer

          The powers of disposition and voting of GFI and GAMCO
with respect to Securities owned beneficially by them on behalf of
their investment advisory clients, of GLI, Mr. Gabelli and GSI with
respect to Securities owned beneficially by them on behalf of the
partnerships which they directly or indirectly manage, and of GIL
and GAL with respect to Securities owned beneficially by it on
behalf of its shareholders, are held pursuant to written agreements
with such clients and partnerships.  The pertinent portions of
forms of such agreements utilized by such Reporting Persons are
filed as Exhibits hereto. 

Item 7.   Material to be Filed as an Exhibit

          The following Exhibits B and D to F are incorporated
herein by reference to Exhibits B and D to F in Schedule 13D of
various Gabelli entities dated June 19, l989 relating to the Common
Stock of Lincoln Telecommunications Company.  The following Exhibit
K is incorporated by reference to Exhibit K in Amendment No. 3 to
Schedule 13D of various Gabelli entities dated January 3, 1989
relating to the Common Stock of Wynn's International.  The
following Exhibit N is incorporated by reference to Exhibit N to
Schedule 13D of various Gabelli entities dated October 9, 1989
relating to the Common Stock of Graphic Technology, Inc.  The
following Exhibit BB is incorporated by reference to Exhibit BB in
Amendment No. 6 to Schedule 13D of various Gabelli entities dated
November 3, 1992 relating to the Common Stock of Hector Communica-
tions. The following Exhibit CC is incorporated by reference to
Exhibit CC in Amendment No. 10 to Schedule 13D of various Gabelli
entities dated November 9, 1992 relating to the Common Stock of The
Liberty Corporation.  The following Exhibit LL is incorporated by
reference to Exhibit LL in the initial Schedule 13D of various
Gabelli entities dated June 27, 1995 relating to the Common Stock
of Pulitzer Publishing.  The following Exhibit RR is incorporated
by reference to Exhibit RR in Amendement No. 16 to Schedule 13D of
various Gabelli entities dated April 23, 1996 relating to the
Common Stock of Aaron Rents, Inc.
   
          Exhibit A:     Joint Filing Agreement 
          Exhibit B:     Pertinent portions of form of investment
                         advisory agreement used by GAMCO Inves-
                         tors, Inc.

          Exhibit D:     Pertinent portions of Gabelli Funds, Inc.
                         advisory agreements.

          Exhibit E:     Pertinent portions of Gabelli Asset Fund
                         and Gabelli Growth Fund voting procedu-
                         res.

          Exhibit F:     Pertinent portions of partnership agree-
                         ments to which Gabelli Associates, GLI
                         and GPP are parties.

          Exhibit K:     Pertinent portions of the Investment
                         Management Agreement of GIL.

          Exhibit N:     Pertinent portions of the Investment
                         Management Agreement of GAL.

          Exhibit BB:    Memorandum of understanding between      
                         Gabelli Funds, Inc., Mario J. Gabelli    
                         and the Federal Communications Commission
                         (dated November 3, 1992).

          Exhibit CC:    Joint motion for approval of memorandm
                         of understanding file with FCC by        
                         Gabelli Funds, Inc., Mario J. Gabelli    
                         and the Federal Communications Commis-
                         sion (dated November 9, 1992).

          Exhibit LL:    Powers of Attorney to Stephen G. Bondi, 
                         Steven M. Joenk, and James E. McKee from
                         Joseph H. Epel.

                         Powers of Attorney to Stephen G. Bondi, 
                         Steven M. Joenk, and James E. McKee from
                         Robert E. Dolan. 

                         Powers of Attorney to Stephen G. Bondi, 
                         Steven M. Joenk, and James E. McKee from
                         Mario J. Gabelli.

          Exhibit RR:    Powers of Attorney to Stephen G. Bondi,
                         Steven M. Joenk, and James E. McKee from
                         Marc J. Gabelli.




















Signature
            After reasonable inquiry and to the best of my know-
ledge and belief, I certify that the information set forth in this
statement is true, complete and correct. 
Dated:    May 17, 1996

                                   GABELLI FUNDS, INC.  
                                   
                                   

                                   By:_________________________
                                      James E. McKee
                                      General Counsel

               
                                   GAMCO INVESTORS, INC.  
                                   
                                   
                                   By:_________________________
                                      Douglas R. Jamieson  
                                      Chief Operating Officer
                                      and Executive Vice President
                                   


                                   GABELLI INTERNATIONAL ADVISORY
                                   SERVICES, LIMITED


                                   By:__________________________
                                      Marc J. Gabelli
                                      Director
                                      by: James E. McKee
                                      Attorney-in-Fact


                                   Mario J. Gabelli


                                   By:____________________________
                                      James E. McKee
                                      Attorney-in-Fact



                                                       Schedule I


              Information with Respect to Executive
            Officers and Directors of the Undersigned 

          Schedule I to Schedule 13D is amended, in pertinent part,
as follows:

          The following sets forth as to each of the executive
officers and directors of the undersigned: his name; his business
address; and his present principal occupation or employment and the
name, principal business and address of any corporation or other
organization in which such employment is conducted.  Unless other-
wise specified, the principal employer of each such individual is
Gabelli Funds, Inc., Gabelli & Company, Inc., or GAMCO Investors,
Inc., the business address of each of which is One Corporate
Center, Rye, New York 10580, and each such individual identified
below is a citizen of the United States.  To the knowledge of the
undersigned, during the last five years, no such person has been
convicted in a criminal proceeding (excluding traffic violations or
similar misdemeanors), and no such person was a party to a civil
proceeding of a judicial or administrative body of competent
jurisdiction as a result of which he was or is subject to a
judgment, decree or final order enjoining future violations of, or
prohibiting or mandating activities subject to, federal or state
securities law or finding any violation with respect to such laws
except as reported in Item 2(d) of this Schedule 13D. 

Gabelli Funds, Inc. 

Directors: 

     Mario J. Gabelli*

     Richard B. Black              Chairman of Raster Image
                                   Processing Systems; Chairman
                                   ECRM; Director of Archetype
                                   and Oak Technology; Director
                                   of The Morgan Group, Inc.;
                                   General Partner of KBA Part-  
                                   ners, Parker Plaza
                                   400 Kelby Street,
                                   Fort Lee, NJ 07029

     Charles C. Baum               Chairman, Director and Chief
                                   Executive Officer of The
                                   Morgan Group, Inc.;
                                   Secretary & Treasurer
                                   United Holdings              
                                   2545 Wilkens Avenue
                                   Baltimore, MD  21223

     Dr. Eamon M. Kelly            President
                                   Tulane University
                                   218 Gibson Hall
                                   6823 St. Charles Avenue
                                   New Orleans, LA  70118

     Marc J. Gabelli               Vice President


Officers:

     Mario J. Gabelli              Chairman, Chief Executive
                                   Officer and Chief Investment
                                   Officer
     
     Steven M. Joenk               Executive Vice President
                                   and Chief Financial Officer






_____________________

     *    Mr. Gabelli is the Chairman, Chief Executive Officer and
Chief Investment Officer of Gabelli Funds, Inc.; Chief Investment
Officer of GAMCO Investors, Inc.; Director/Trustee of all
registered investment companies advised by Gabelli Funds, Inc.;
Chairman and Chief Executive Officer of Lynch Corporation; Director
of Spinnaker Industries, Inc.; Director of the Morgan Group, Inc. 

     Stephen G. Bondi              Vice President - Finance

     James E. McKee                Vice President, General 
                                   Counsel and Secretary


GAMCO Investors, Inc.

Directors:

     Douglas R. Jamieson
     Joseph R. Rindler, Jr.
     Regina M. Pitaro
     Steven M. Joenk      
     F. William Scholz, II

Officers:
     
     Mario J. Gabelli              Chief Investment Officer

     Douglas R. Jamieson           Chief Operating Officer and
                                   Executive Vice President 

     Steven M. Joenk               Vice President
  
     Stephen G. Bondi              Vice President

     James E. McKee                Vice President, General       
                                   Counsel and Secretary


Gabelli Securities, Inc.

Directors:

     Robert W. Blake               President of W.R. Blake
                                   & Sons, Inc.
                                   196-20 Northern Boulevard
                                   Flushing, NY  11358

     Douglas DeVivo                General Partner of ALCE
                                   Partners, L.P.
                                   One First Street, Suite 16
                                   Los Altos, CA  94022

     Ronald L. Gallatin            Consultant
                                   Gabelli Securities, Inc.
                                   One Corporate Center
                                   Rye, NY  10580


     Joseph R. Rindler, Jr.        Managing Director
                                   GAMCO Investors, Inc.
                                   One Corporate Center
                                   Rye, NY  10580

     Francine Sommer               Chief Executive Officer of
                                   General Partner of Gabelli
                                   Multimedia Partners, L.P.
                                   One Corporate Center
                                   Rye, NY  10580

Officers:

     Steven M. Joenk               Executive Vice President

     Stephen G. Bondi              Vice President

     James E. McKee                Secretary



Gabelli & Company, Inc.

Directors:

     James G. Webster, III         Chairman 
     
     Steven M. Joenk               See above

     Stephen G. Bondi              See above

Officers:

     James G. Webster, III         Chairman 

     Steven M. Joenk               Executive Vice President

     Stephen G. Bondi              Vice President 

     Walter K. Walsh               Compliance Officer

     James E. McKee                Secretary



GLI, Inc.
Directors:

     Mario J. Gabelli              See above-Gabelli Funds, Inc.


Officers:

     Mario J. Gabelli              Chairman and Chief Investment
                                   Officer

     Stephen G. Bondi              Vice President



Gabelli Associates Limited

Directors:

     Mario J. Gabelli              See above-Gabelli Funds, Inc.

     MeesPierson  (Cayman)         British American Centre   
     Limited                       Dr. Roy's Drive- Phase 3
                                   Georgetown, Grand Cayman   
                                   Cayman Islands, British        
                                   WestIndies

     MeesPierson  (Cayman)         British American Centre   
     Limited                       Dr. Roy's Drive- Phase 3
                                   Georgetown, Grand Cayman   
                                   Cayman Islands, British             
                                   WestIndies
     
Officers:

     Mario J. Gabelli              Chief Investment Officer

     Kevin Bromley                 Vice President, Treasurer and
                                   Assistant Secretary

     Sandra Wight                  Secretary and Assistant Treasurer



Gabelli International Limited

Directors:

     Mario J. Gabelli              See above-Gabelli Funds, Inc.
   
     MeesPierson  (Cayman)         British American Centre   
     Limited                       Dr. Roy's Drive- Phase 3
                                   Georgetown, Grand Cayman   
                                   Cayman Islands, British West Indies

Officers:

     Kevin Bromley                 Vice President, Treasurer, and      
                                   Assistant Secretary                 
                                   MeesPierson (Cayman) Limited
                                   British American Centre  
                                   Dr. Roy's Drive- Phase 3   
                                   Georgetown, Grand Cayman    
                                   Cayman Islands, British West Indies







     Sandra Wight                  Secretary and Assistant Treasurer
                                   Assistant Secretary                 
                                   MeesPierson (Cayman) Limited
                                   British American Centre  
                                   Dr. Roy's Drive- Phase 3   
                                   Georgetown, Grand Cayman    
                                   Cayman Islands, British West Indies



Gabelli Asset Management Company 
International Advisory Services Ltd.

Directors:

     Marc J. Gabelli               See above-Gabelli Funds, Inc.

     Stephen G. Bondi              See Above-Gabelli Funds, Inc.

     Joseph R. Rindler, Jr.        See above-GAMCO Investors, Inc.

     Michael J. Burns              Appleby, Spurling & Kempe
                                   Cedar House
                                   41 Cedar Avenue
                                   Hamilton, HM12
                                   Bermuda             

     Douglas Molyneux              Appleby, Spurling & Kempe
                                   Cedar House
                                   41 Cedar Avenue
                                   Hamilton, HM12
                                   Bermuda        


Lynch Corporation
8 Sound Shore Drive
Greenwich, CT  06830

Directors:

     Paul J. Evanson               President               
                                   Florida Light & Power Co.
                                   P.O Box 14000
                                   700 Universe Blvd.
                                   Juno Beach, Fl 33408

     Morris Berkowitz              Business Consultant
                                   163-43 Willets Point Blvd.
                                   Whitestone, NY 11357

     Mario J. Gabelli              See above-Gabelli Funds, Inc.

     Paul Woolard                  Business Consultant
                                   116 East 68th Street
                                   New York, NY 10021

     E. Val Cerutti                Business Consultant          
                                   Cerutti Consultants 
                                   227 McLain Street
                                   Mount Kisco, NY   10549

     Ralph R. Papitto              Chairman of the Board
                                   AFC Cable Systems, Inc.
                                   50 Kennedy Plaza
                                   Suite 1250
                                   Providence, RI  02903

     Salvatore Muoio               Vice President 
                                   Lazard Freres & Co. L.L.C.
                                   One Rockefeller Plaza
                                   New York, NY  10020-2327

Officers:

     Mario J. Gabelli              Chairman and Chief Executive   
                                   Officer

     Joseph H. Epel                Treasurer

     Robert E. Dolan               Chief Financial Officer 

     Carmine Ceraolo               Assistant Controller

     Robert A. Hurwich             Vice President-Administration,
                                   Secretary and General Counsel


Spinnaker Industries, Inc.
600 N. Pearl Street 
Suite 2160
Dallas, TX  75201

Directors:

     Joseph P. Rhein               5003 Central Avenue     
                                   Ocean City, NJ  08226
                                   
     Richard J. Boyle              The Boyle Group, Inc.             
                                   6110 Blue Circle Drive
                                   Suite 250           
                                   Minnetonka, MN  55343

     Ned N. Fleming, III           Boyle, Fleming, 
                                   George & Co., Inc.            
                                   600 N. Pearl Street
                                   Suite 2160
                                   Dallas, TX  75201

     Mario J. Gabelli              See above-Gabelli Funds, Inc.

     Robert E. Dolan               See above Lynch Corporation


     Anthonie C. van Ekris         Chairman and Chief 
                                   Executive Officer
                                   Balmac International, Inc.
                                   61 Broadway
                                   Suite 1900
                                   New York, NY  10006

Officers:

     James W. Toman                Controller          

     Ned N. Fleming, III           President

     Richard J. Boyle              Chairman and
                                   Chief Executive Officer

     Robert A. Hurwich             Secretary

     Mark A. Matteson              Vice President, Corporate
                                   Development


Entoleter, Inc.
251 Welton Street
Hamden, CT  06517

Directors:

     Ned N. Fleming, III           See above-Spinnaker

     Mark A. Matteson              See above-Spinnaker

     James W. Toman                See above-Spinnaker

     Robert P. Wentzel             See above Entoleter

     James Fleming                 230 Saugatuck Avenue, Unit 8
                                   Westport, CT  06880

Officers:

     James W. Toman                Chief Financial Officer
                                   and Secretary

     Robert P. Wentzel             President

     Anthony R. Massaro            Vice President-Manufacturing



Western New Mexico Telephone Company
314 Yankee Street
Silver City, NM  88062

Directors:

     Jack C. Keen                  Chairman

     Jack W. Keen                  President

     Dr. Brian E. Gordon           Vice President

     Mary Beth Baxter              Secretary & Treasurer

     Robert E. Dolan               See above-Lynch Corporation

     Robert A. Hurwich             See above-Lynch Corporation

     Carmine Ceraolo               See above-Lynch Corporation

Officers:

     Jack C. Keen                  Chairman of the Board

     Jack W. Keen                  President

     Jack L. Bentley               Executive Vice President

     Dr. Brian E. Gordon           Vice President

     Charles M. Baxter             Sr. Vice President-Operations
     
     Mary Beth Baxter              Secretary & Treasurer

     Robert A. Hurwich             Assistant Treasurer



Inter-Community Telephone Company
P.O. Box A
Nome, ND  58062

Directors:

     Mary J. Carroll               See above-Lynch Corporation

     Carmine P. Ceraolo            See above-Lynch Corporation
                                   
     Robert E. Dolan               See above-Lynch Corporation

     Joseph H. Epel                See above-Lynch Corporation

     Robert A. Hurwich             See above-Lynch Corporation

     Leone A. Nilsen               President

     Roger J. Nilsen               P.O. Box 146
                                   Hannaford, ND 58448

     Duane A. Plecity              Secretary

     Harry B. Snyder               P.O. Box 131
                                   Buffalo, ND  58011
                                   
     Robert Snyder                 200 Broadway South
                                   Buffalo, ND  58011

Officers:

     Leone A. Nilsen               President
     
     Robert Snyder                 Vice President 
     
     Duane A. Plecity              Secretary
     
     Harry B. Snyder               Treasurer

     Joseph H. Epel                Assistant Treasurer

     Robert A. Hurwich             Assistant Secretary



Lynch Telecommunications Corporation
8 Sound Shore Drive
Greenwich, CT  06830

Directors:

     Richard A. Kiesling           2801 International Lane
                                   Suite 207
                                   Madison, WI  53740           

     Jack C. Keen                  See above-Western New Mexico
                                   Telephone Company

     Robert A. Snyder              See above-Inter-Community
                                   Telephone Company

Officers:

     Robert A. Hurwich             Secretary

     Mary Beth Baxter              Treasurer and 
                                   Assistant Secretary

     Robert E. Dolan               Controller



Lynch Telephone Corporation
8 Sound Shore Drive
Greenwich, CT  06830

Directors:

     Robert E. Dolan               Controller

     Jack C. Keen                  Chairman

Officers:

     Jack C. Keen                  Chairman

     Jack W. Keen                  President

     Robert A. Hurwich             Secretary

     Mary Beth Baxter              Treasurer and 
                                   Assistant Secretary

     Robert E. Dolan               Controller


                                                                  
                 SCHEDULE II                                
               INFORMATION WITH RESPECT TO                        
     TRANSACTIONS EFFECTED DURING THE PAST SIXTY DAYS OR          
     SINCE THE MOST RECENT FILING ON SCHEDULE 13D (1)             
                                                                  
     
                              SHARES PURCHASED        AVERAGE     
               DATE           SOLD(-)                 PRICE(2)    
                                                                  

COMMON STOCK-IDEX CORP                                            

GABELLI FUNDS, INC.                                               
          THE GABELLI SMALL CAP GROWTH FUND                       
               3/27/96            1,500-           39.8487        
               3/18/96            1,500-           38.1154        
               
          THE GABELLI EQUITY TRUST,INC.                           
               4/08/96              800-           39.3237        
               
          THE GABELLI ASSET FUND                                  
               3/27/96            1,000-           39.8487        
               3/25/96            2,000-           39.3237        
               3/18/96            3,000-           38.1987        
               3/15/96            6,500-           37.9487        
               
GAMCO INVESTORS, INC.                                             
               5/13/96           75,000-             *DO          
               5/02/96              300-           39.7500        
               5/01/96            1,500-             *DO          
               4/29/96              300-           38.7500        
               4/23/96              600-             *DO          
               4/18/96            4,500-           40.5000        
               4/08/96            1,500-           39.5000        
               3/29/96            1,000-           38.3750        
               3/28/96              750-           39.5000        
               3/26/96            1,250-           39.6250        
               3/22/96            4,000-             *DO          
               



(1) UNLESS OTHERWISE INDICATED, ALL TRANSACTIONS WERE EFFECTED    
    ON THE NY STOCK EXCHANGE.                                     
(2) PRICE EXCLUDES COMMISSION.                                    
(*) RESULTS IN CHANGE OF DISPOSITIVE POWER AND BENEFICIAL         
    OWNERSHIP.                                                    
    

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