Cumming, Linnæus, b. 1843. [from old catalog] · New York, D. Van Nostrand · leaf 79
nthe under surface of which are secured four to eight lightmagnetic needles. The card swings in a compass-box on a 6o Electricity. [Book I. pivot placed at its centre, the box having a pointer whichcorresponds to the direction of the ships head. The box issupported on gimbals (Fig. 39)—an… … Fig. 40. 45. Effect of iron masses in Ships.—As soon as ironentered largely into the construction of ships, errors in thecompass, depending on the terrestrial magnetic induction,appeared. This effect is illustrated by holding a bar of softiron parallel to the dipping needle, when the lower end…
Electricity
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
