<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEETS AS OF MARCH 31, 1997, JUNE 30, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)
AND THE STATEMENTS OF OPERATIONS FOR THE QUARTERLY PERIOD ENDED MARCH 31, 1997,
JUNE 30, 1997 AND SEPTEMBER 30, 1997, 1997 (UNAUDITED) AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS INCLUDED AS PART OF ITS
QUARTERLY REPORT ON FORM 10-Q FOR THE RESPECTIVE PERIODS THEN ENDED
</LEGEND>
       
                                                                       
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JAN-01-1997             JAN-01-1997             JAN-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                         184,259                 156,288                 150,339
<SECURITIES>                                         0                       0                       0
<RECEIVABLES>                                   65,490                  47,788                  43,160
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                               249,749                 204,076                 193,499
<PP&E>                                       1,288,513               1,161,294               1,034,198
<DEPRECIATION>                                 900,423                 812,906                 734,071
<TOTAL-ASSETS>                                 637,839                 552,464                 493,626
<CURRENT-LIABILITIES>                                0                       0                       0
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                             0                       0                       0
<OTHER-SE>                                     637,839                 552,464                 493,626
<TOTAL-LIABILITY-AND-EQUITY>                   637,839                 552,464                 493,626
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                                44,196                  70,320                 105,370
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                   23,006                  29,722                  35,731
<OTHER-EXPENSES>                                     0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                   0                       0                       0
<INCOME-PRETAX>                                 42,212                       0                       0
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                                  0                       0                       0
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                    42,212                  82,063                 123,409
<EPS-PRIMARY>                                        0                       0                       0
<EPS-DILUTED>                                        0                       0                       0