...In 1884, at the International Meridian Conference held in
Washington, D. C., representatives from twenty-six countries voted to
make the common practice official. They declared the Greenwich meridian
the prime meridian of the world. This decision did not sit well with
the French, however, who continued to recognize their own Paris
Observatory meridian, a little more than two degrees east of Greenwich,
as the starting line for another twenty-seven years, until 1911. (Even
then, they hesitated to refer directly to Greenwich mean time,
preferring the locution "Paris Mean Time, retarded by nine minutes
twenty-one seconds.)