Exhibit 2(c)


Form of Voting Agreement dated as of June 9, 1997, said form of Voting Agreement
being substantially identical and signed by the following individuals:

Barry M. Davis
Davis Venture Partners, L.P.
Seymor G. Mandell
Melvin N. Miller
James H. Simons
Lord Jim Trust

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                                VOTING AGREEMENT

     VOTING AGREEMENT ("Agreement") dated as of June 9, 1997, between
Halliburton Company, a Delaware corporation (the "Acquiror"), and Barry M. Davis
(the "Shareholder"), a holder of common shares, par value $0.01 per share, of
NUMAR Corporation, a Pennsylvania corporation (the "Company").

                                   RECITALS:

     The Shareholder beneficially owns an aggregate of 723,144 common shares
(together with any additional common shares as to which beneficial ownership is
acquired by any member of the Shareholder Group described below, the "Company
Shares"), par value $0.01 per share ("Company Common Shares"), of the Company.

     The Acquiror is prepared to enter into an Agreement and Plan of Merger with
the Company (the "Plan") providing for the merger of a wholly owned subsidiary
of Acquiror with and into the Company and the conversion in such merger of each
Company Common Share into the number of shares of the Common Stock, par value
$2.50 per share, of the Acquiror set forth in the Plan (the "Merger").

     To facilitate the Merger, the Shareholder is willing to enter into certain
arrangements with respect to the Company Shares.

     NOW, THEREFORE, in consideration of the premises set forth above, the
mutual promises set forth below, and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:
 
1.   Shareholder's Support of the Merger.  From the date hereof until December
31, 1997, or, if earlier, termination of the Plan:

          (a)  Except as contemplated by the Plan or hereby, neither the
     Shareholder nor any Person controlled by the Shareholder, other than the
     Company and its subsidiaries (collectively, the "Shareholder Group"), will,
     directly or indirectly, sell, transfer, pledge or otherwise dispose of, or
     grant a proxy with respect to, any Company Shares to any Person other than
     any member of the Shareholder Group or the Acquiror or its designee, or
     grant an option with respect to any of the Company Shares or enter into any
     other agreement or arrangement with respect to any of the Company Shares.

          (b)  The Shareholder agrees that the Shareholder will vote, and will
     cause each member of the Shareholder Group to vote, all Company Shares
     entitled to vote and beneficially owned by such Persons (i) in favor of the
     Merger and (ii), subject to the provisions of paragraph (c) below, against
     any combination proposal or other matter that may 


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     IN WITNESS WHEREOF, the Shareholder has executed this Agreement and the
Acquiror has caused this Agreement to be duly executed by an officer, thereunto
duly authorized, all as of the day and year first above written.

                                  HALLIBURTON COMPANY

                                  By:/s/ Lester L. Coleman
                                    --------------------------------------------
                                    Lester L. Coleman
                                    Executive Vice President and General Counsel
 
                                  SHAREHOLDER
                                  
                                  /s/ Barry M. Davis
                                  ----------------------------------------------
                                  Barry M. Davis

 
                                      -7-

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