APPENDIX II
DISCOVERIES MADE BY WILLIAM GILBERT—DESIGNATED IN
“DE MAGNETE” BY THE LARGER ASTERISKS
(Alluded to in the Gilbert A.D. 1600 Article, p. 83)
Book I. chap. iii. The loadstone ever has and ever shows its poles, which look toward the poles of the earth and move toward them and are subject to them.
Book I. chap. vi. The loadstone attracts iron ore, as well as the smelted metal, the best iron, acies, being the most readily attracted.
Book I. chap. ix. Iron ore attracts iron ore.
Book I. chap. x. Iron ore has and acquires poles, and arranges itself with reference to the earth’s poles.
Book I. chap. xi. Wrought-iron, not magnetized by the loadstone, attracts iron.
Book I. chap. xii. A long piece of iron, even not magnetized, assumes a north and south direction.
Book I. chap. xiii. Smelted iron has in itself fixed north and south parts, magnetic activity, verticity, and fixed vertices or poles.
Book II. chap. ii. Not only do amber and jet attract light substances: the same is done by the diamond....
Book II. chap. ii. When the atmosphere is very cold and clear, the electrical effluvia of the earth offer less impediment.
Book II. chap. xxv. A strong, large, loadstone increases the power of another loadstone, and also the power of iron.
Book II. chap, xxxiv. Why a loadstone is of different power in its poles as well in the north as in the south regions (two experiments).
Book III. chap. xii. Iron becomes magnetized when red-hot and hammered in the magnetic meridian; also when the iron bars have, for a long time, lain fixed likewise in the north and south position (two experiments).
Book III. chap. xv. Two more experiments to show that the poles, equator, centre, are permanent and stable in the unbroken loadstone; when it is reduced in size and a part taken away, they vary and occupy their positions.
Book IV. chap. ii. Variation is due to inequality among the earth’s elevations.
Book V. chap. ii. Illustration of the direction and dip of a terrella representing the earth relative to the standard representation of the globe of the earth, at north latitude 50°.
Book V. chap. iii. Instrument for showing by the action of a loadstone, the degree of dip below the horizon in any latitude.
Book V. chap. vi. Of the ratio of dip to latitude and the cause thereof.
Book V. chap. xi. Of the formal magnetical act spherically effused.