National Geographic : 1925 Nov
Photographs by Jacob Gayer THE MACHINE WITH WHICH THE TIDES AT ETAH SIGNED TIIEIR FIRST AUTOGRAPH Lieutenant Benjamin H. Rigg carried with him to Etah an automatic tide gauge which recorded every move of the sea. Because of an unusual tidal range, the piping taken to the Arctic was not long enough and an extension had to be made of boards from airplane crates. AK-KOM-A-DING-WAWATCHES LIEUTENANT RIGG AT HIS SCIENTIFIC WORK IN ETAH Over the tent flies the flag ofthe United States Coast and Geodetic Survey, under which Rigghas worked on our South Atlantic coast, off Alaska, and in the Sulu Sea. The magnetic force atEtah isonly one tenth as strong as at New York, so compass readings require great care.