Exhibit 99.4

                 MARKETSPAN JOINS CROSS BAY PIPELINE DEVELOPMENT

Brooklyn and Hicksville, N.Y., August 4, 1998 - MarketSpan Corporation (NYSE:MN)
announced today that its subsidiary, KeySpan Energy Development Corporation, has
joined Duke Energy Corporation  (NYSE:DUK) and the Williams Companies (NYSE:WMB)
in developing the Cross Bay[SM] pipeline.

The Cross Bay[SM]  pipeline will transport gas from interstate  pipelines in New
Jersey to New York City and Long Island.  These existing pipelines,  operated by
Texas  Eastern  Transmission  Corporation  and  Transcontinental  Gas Pipe Lines
Corporation (TRANSCO), are owned by Duke Energy and Williams, respectively.

In the first  stage of  development,  expected  to cost $45  million,  the Cross
Bay[SM] group will build new compression facilities and expand current pipelines
to transport  an  additional  125 million  cubic feet of gas per day to New York
City and Long Island. The new system is scheduled to begin operating in November
2000,  supplying customers served by Brooklyn Union and Consolidated  Edison. To
meet future  regional  demand,  Cross Bay[SM] may be expanded to carry up to 700
million cubic feet per day.

During an open season  planned for August  1998,  the Cross  Bay[SM]  group will
invite  companies to  communicate  their  interests in  subscribing  to firm gas
transportation  capacity from the  pipeline.  The Cross Bay[SM] group expects to
file its plans with the Federal Energy Regulatory Commission in November 1998.

"Cross  Bay[SM] is another  step toward our goal of  becoming a dominant  energy
company in the Northeast.  By delivering additional volumes of clean natural gas
to the New York  area,  Cross  Bay[SM]  will  enhance  shareholder  value  while
supporting the growth of a competitive  energy market in this densely  populated
location,"  said  Robert B.  Catell,  chairman  and chief  executive  officer of
MarketSpan Corporation.

"Cross Bay[SM] is a team effort. Duke Energy and Williams provide the foundation
for  delivering  reliable  gas  supplies  to the  New  York  metropolitan  area.
MarketSpan  provides  access to this  growing gas  market,"  said Robert  Evans,
president of Texas Eastern and Algonquin Gas Transmission Company.

"Adding  MarketSpan  to the Cross Bay[SM]  pipeline  group will help ensure that
this project is well positioned to satisfy the future needs of New York and Long
Island - two  dynamic  gas  markets,"  said Cuba  Wadlington,  Jr.,  senior vice
president and general manager, TRANSCO pipeline system.

MarketSpan   Corporation   is  an  energy   holding   company  whose   principal
subsidiaries,  including  Brooklyn Union,  provide gas and electric  services to
more than two million  businesses and households in Long Island and parts of New
York  City.  This  territory  covers  1,417  square  miles and a  population  of
approximately  6.7 million people.  MarketSpan  companies also have interests in
domestic oil and gas  exploration  and  production,  gas  transmission,  and gas
storage. Other MarketSpan holdings include unregulated energy services companies
operating in the Northeast. Further, MarketSpan has international investments in
gas distribution and gas transmission.  Additional MarketSpan information can be
found at www.marketspancorp.com.