In an earlier post,
we showed how radio was being used in 1924 for accurate measurements of longitude. And the newspaper a hundred years ago today, November 21, 1914, shows the work that was taking place then. This clipping from the New York Sun shows measurements of longitude being made between Paris and Washington.
The Eiffel Tower radio station continued in service throughout the war, and a hundred years ago, it was busy comparing time signals with its counterpart in Arlington, Virginia, station NAA. By comparing the instant of local noon at both locations, the tests were able to very accurately measure the difference in longitude. The time difference between the two observatories was found to be 5 hours, 17 minutes, and 36.658 seconds. This corresponds to a difference in longitude of 79.40274 degrees.