A history of electricity : the intellectual rise in electricity from antiquity to the days of Benjamin Franklin (1898)
Benjamin, Park, 1849-1922 · New York : J. Wiley & Sons · leaf 185
eshadows of the pins coincide with the longitudinal axisof the bar; and simply notes the angle between the finaldirection of the bar and the north and south line markedon the edge of his bowl. To do this he has to hold thebowl steady with one hand, as he describes, and movethe bar around its center… … PEREGRINUS FI.OATING COMPASS.* wind, by turning his bar until it is in line with the direc-tion in which the wind blows. Or, he can find theazimuth of the moon, or a star, by placing his bar in thedirection of the heavenly body. Of course it is only astep beyond this, and one that was probably…
Electricity · Magnetism
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