William Gilbert of Colchester, Physician of London; On the Loadstone and Magnetic Bodies and on the Great Magnet the Earth. a New Physiology Demonstra (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 edition. Excerpt: ...a loadstone, attract more strongly than the loadstone attracts any iron; but once they are in contact with each other they unite more strongly, and become as it were clamped together, though with the same forces at work the substance remains the same.1 CHAPTER XVIII. AN ARMED LOADSTONE DOES NOT ENDOW WITH GREATER FORCE MAGNETIZED IRON THAN DOES AN UNARMED ONE. Take two pieces of iron, one magnetized with an armed and the other with an unarmed loadstone, and apply to one of them a weight of iron proportioned to its powers: the other loadstone will lift the same weight, and no more. Two needles also turn with the same velocity and constancy toward the poles of the earth, though one needle may have been touched by an armed magnet and the other by one unarmed. 1 Sir Kenelm Digby, "The Nature of Bodies," 1645, Chap. XXII, page 243; Jacobi Rohaulti, Physica, Londini 1718, Paf. Ill, Cap. VIII, p. 403, or the English translation by Dr. Clarke, London, 1728, Vol. II, page 181; Ath. Kircheri, Magnts; live de arte Magnetica, 1643, Lib. I, Pars II, page 63; Nicolao Cabeo, Philosophia Magneiica, 1629, Lib. IV, Cap. XLII, page 407. CHAPTER XIX. THAT UNITION IS STRONGER WITH AN ARMED LOADSTONE; HEAVIER WEIGHTS ARE THUS LIFTED; THE COITION IS NOT STRONGER, BUT COMMONLY WEAKER. That an armed loadstone lifts a greater weight is evident to all; but iron is drawn from the same distance, or rather from a greater distance, to the loadstone when the stone is without the iron helmet. This is to be tried with two pieces of iron of the same weight and form at. equal distance, or with one and the same needle, tested first with the armed then with the unarmed stone, at equal distances. CHAPTER XX. That An Armed Magnet Lifts Another, And That One A Third: ...