On the Magnet, by William Gilbert

Chap. xiiii.

The Placing of a Loadstone above or below a magnetick body suspended in æquilibrium changes neither the power nor the verticity of the magnetick body.

Q uietly to pass this over would be improper, because a recent error arising from a defective observation of Baptista Porta must be overthrown; on which he (by an unfortunate repetition) even writes three chapters, namely, the 18th, the 31st, and the 42nd. For if a loadstone or a piece of magnetick iron, hanging in æquilibrium or floating on water, is attracted and disposed toward certain definite points, when you bring above it a piece of iron or another loadstone, it will not, if you afterward put the same215 below it, turn round to the contrary parts; but the same ends of the iron or the loadstone will always be directed toward the same ends of the stone, even if the loadstone or the iron is suspended in any way in æquilibrium or is poised on a needle, so that it can turn round freely. He was deceived by the irregular shape of some stone, or because he did not arrange the experiment suitably. Wherefore he is led astray by a vain opinion, and thinks he may infer that, just as a stone has an arctic and antarctic pole, so also it has a western and an eastern, and an upper and a lower pole. So from foolish ideas conceived and admitted arise other fallacies.

215 Page 144, line 14. Page 144, line 14. ijdem.— The editions of 1628 and 1633 erroneously read iisdem.

http://ebooks.adelaide.edu.au/g/gilbert/william/on-the-magnet/book3.14.html

Last updated Friday, March 14, 2014 at 22:17