Exhibit 4.01 (f)



                           1991 SUPPLEMENTAL INDENTURE


      This  1991  Supplemental  Indenture,  made as of March  15,  1991,  by and
between  EQUITABLE   RESOURCES,   INC.  (formerly  Equitable  Gas  Company),   a
Pennsylvania  corporation  having its  principal  office at 420 Boulevard of the
Allies,  Pittsburgh,  Pennsylvania  15219 (the  "Company"),  and  BANKERS  TRUST
COMPANY,  a New York  corporation  having its  principal  office at Four  Albany
Street, New York, New York 10006, as successor trustee (the "Trustee") under the
Indenture dated as of April 1, 1983 (the "Indenture") from the Company,

                                WITNESSETH THAT:

      WHEREAS,  Section  901(5) of the  Indenture  provides  that,  without  the
consent of any Holders, the Company, when authorized by a Board Resolution,  and
the Trustee  may enter into a  supplemental  indenture  for the  purpose,  among
others,  of changing or  eliminating  any of the  provisions  of the  Indenture,
provided that any such change or  elimination  shall become  effective only when
there is no Security Outstanding of any series created prior to the execution of
such supplemental indenture which is entitled to the benefit of such provision;

      WHEREAS,  four  series  of  Securities  have  been  created  prior  to the
execution hereof,  three of which series, to wit: the Debentures,  8 1/4% Series
Due July 1, 1996,  the  Debentures,  7 1/2%  Series  Due July 1,  1999,  and the
Debentures,  9.90%  Series Due April 15,  2013,  remain  Outstanding  in varying
principal  amounts  and are  entitled to the  benefit of the  provisions  of the
Indenture eliminated hereby;

      WHEREAS,  the execution and delivery of this 1991  Supplemental  Indenture
have been duly authorized by a Board Resolution.

      NOW,  THEREFORE,  the  parties  hereto,  for and in  consideration  of the
premises, and intending to be legally bound hereby, do hereby agree to eliminate
from the Indenture, in their entirety,  Section 1004, containing a limitation on
liens,  and Section 1005,  containing a limitation upon additional  funded debt,
provided that the elimination of each of these provisions shall become effective
only when there is no Security  Outstanding  of any series  created prior to the
execution  of this  Supplemental  Indenture  which is entitled to the benefit of
such provisions. After the elimination of the above-mentioned provisions becomes
effective,  all  references  to  such  provisions  contained  elsewhere  in  the
Indenture shall be deemed also to have been eliminated and given no effect.

      This  instrument is and for all purposes shall be considered  supplemental
to the Indenture which, as heretofore  supplemented and as supplemented  hereby,
shall remain in full force and effect.

      Terms  capitalized  herein and defined in the Indenture are used herein as
therein defined.

      The  Trustee  does  hereby  approve  the  form of this  1991  Supplemental
Indenture.

      WITNESS  the due  execution  hereof  as of the day and  year  first  above
written.

                                              EQUITABLE RESOURCES, INC.


                                              By
                                                 -------------------------------
                                                  Vice President and Treasurer

[Corporate Seal]

ATTEST:



Corporate Secretary

                             BANKERS TRUST COMPANY,
                                   as Trustee


                                              By

                                              Title

[Corporate Seal]

ATTEST:



Authorized Officer





COMMONWEALTH OF PENNSYLVANIA         )
                                              )  ss:
COUNTY OF ALLEGHENY                           )


      On this  _________  day of  ______________________,  1991,  before me, the
undersigned   officer,   personally  appeared   _________________________,   who
acknowledged  himself to be Vice President and Treasurer of Equitable Resources,
Inc., a  corporation,  and that he as such officer,  being  authorized to do so,
executed the foregoing  instrument for the purposes therein contained by signing
the name of the corporation by himself as such officer.

      IN WITNESS WHEREOF, I hereunto set me hand and official seal.


                                              Notary Public

My Commission expires:




COMMONWEALTH OF NEW YORK                      )
                                              )  ss:
COUNTY OF NEW YORK                            )



      On this  _________  day of  ______________________,  1991,  before me, the
undersigned   officer,   personally  appeared   _________________________,   who
acknowledged himself to be A _______________________ of Bankers Trust Company, a
corporation,  and that he as such officer,  being  authorized to do so, executed
the foregoing  instrument for the purposes therein contained by signing the name
of the corporation by himself as such officer.

      IN WITNESS WHEREOF, I hereunto set me hand and official seal.


                                              Notary Public


My Commission expires: