. The Earth beneath the sea : History . iOO* IJC laO* 160* leO' 160* 140" IJO* 100* 80* 60* 40* 20' 20* 40* 60* 80* Fig. 2. Tracks of Project Magnet. (After Vestine, 1960, fig. 4.) taking a reading. The published accounts are curiously reticent about this important point; even the period of the Carnegie's gimbals is not stated. Azimuth was then, as now, determined by astronomical observation; this in- volves not only the observation of the direction of the sun or of a star, but also the determination of the vertical. It is not necessary to describe here the compasses, dip circles, earth i
. The Earth beneath the sea : History . iOO* IJC laO* 160* leO' 160* 140" IJO* 100* 80* 60* 40* 20' 20* 40* 60* 80* Fig. 2. Tracks of Project Magnet. (After Vestine, 1960, fig. 4.) taking a reading. The published accounts are curiously reticent about this important point; even the period of the Carnegie's gimbals is not stated. Azimuth was then, as now, determined by astronomical observation; this in- volves not only the observation of the direction of the sun or of a star, but also the determination of the vertical. It is not necessary to describe here the compasses, dip circles, earth inductors, deflectors and other instruments used, since they are now only of historical interest. A very detailed description of their final forms has been given by Bauer et al. (1917). In recent years two basic improvements have been made. First, gyro- stabilized platforms have become available and, secondly, electronic techniques
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
