Page:On the Magnet - Gilbert (1900 translation of 1600 work).djvu/176

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154
WILLIAM GILBERT

thence along the coasts of Spain, France, England, Belgium, Germany, Denmark, and Norway, there lie on the right hand and toward the east a continent and extensive connected regions, and on the left extensive seas and a vast ocean lie open far and wide, it is consonant with the theory (as has been carefully observed by many) that magnetical bodies should turn slightly to the East from the true pole toward the stronger and more remarkable elevations of the earth. But it is far otherwise on the eastern shores of northern America; for from Florida by Virginia and Norumbega to Cape Race and away to the north the versorium is turned toward the west. But in the middle spaces, so to speak, as in the more westerly Azores, it looks toward the true pole. That any magnetick body turns itself similarly to the same regions of the earth is not, however, because of that meridian or because of the concordancy of the meridian with any magnetick pole, as the crowd of philosophizers reckon, for it is not so throughout the whole of that meridian. For on the same meridian * near Brazil something very different occurs, as we will show further on. The variation (cæteris paribus) is always less near the æquator, greater in higher latitudes, with the limitation that it be not very near the pole itself. Hence the variation is greater on the coast of * Norway and Belgium than on the coast of Morocco or Guinea: greater also near Cape Race than in the harbours of Norumbega or of Virginia. On the coast of Guinea magnetick implements deviate by a third part of one rumbe to the East: in Cape Verde Islands by a half: on the coast of Morocco by two thirds: in England at the mouth of the Thames by a whole rumbe: and at London by nearly eleven degrees and one third. For indeed the moving magnetick virtue is stronger in a higher latitude; and the larger regions extending toward the poles dominate the more, as is easily apparent anywhere on a terrella. For as in the case of true Direction magnetick bodies tend toward the pole (namely, toward the stronger end, the whole earth causing the motion), so also do they incline a little toward the stronger and higher parts by the action of the whole along with the conjoint action of iron bodies.

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