Porta, Giambattista della, 1535?-1615 · London : Printed for Thomas Young, and Samuel Speed, and are to be sold at the three Pigeons, and at the Angel in St. Paul's Church-yard · leaf 208
7 'hat the ferce of North and South is vigorous in the points, BUt what is more wonderful ? Though the force retreats to the middle of the ftone, yet it doth not fend it felf forth by the middle, but by the extream parts of the ft one, and lies Dill in the middle, as if it were afleep ; but ic is… … mu ft fay. Chap. VII. That by the touching of other ft ones , thofe points will not change their forces,, ANd becaufe I faid that the Load-ftone doth not always hold its forces equal, but that one ftone is more powerful in operation then another, for feme are faint and weak;I fhall put the firft…
Science -- Early works to 1800 · Magic · Alchemy · Industrial arts -- Early works to 1800
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