National Geographic : 1944 Nov
Charting a World at War How Far Does the Compass Needle Veer from True North? These Instruments Tell John Hershberger, left, in charge of the Magnetic Station at Cheltenham, Maryland, makes an observa tion with a sensitive Cooke magnetometer (page 634). His assistants use an earth inductor (center) and another magnetometer (right). Recordings like these, made all over the world, enable mariners to allow for the variation of their compass needle wherever they may be. Lt. Comdr. John Bowie, Jr. Survey Field Workers Follow Army Engineers up the Alaska Highway The open-air kitchen, built in 1942 by the 83d Army Engineers along the Donjek River bed in the Yukon, was a welcome find for this Coast and Geodetic Survey triangulation party the following summer.