Page:On the Magnet - Gilbert (1900 translation of 1600 work).djvu/92

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WILLIAM GILBERT

approach as soon as they have entered within the orbe of the magnetick forces, because they were possessed by it before, connected and united with it in a perfect union; & they have immediately an absolute continuity within that orbe, & have been joined on account of their harmony, though their bodies may have been disjoined. For the iron is not taken possession of and allured by material effluvia, after the manner of electricks, but only by the immaterial action of its form or an incorporeal progression, which in a piece of iron as its subject acts and is conceived, as it were, in a continuous homogeneous body, and does not need more open ways. Therefore (though the most solid substances be interposed) the iron is still moved and attracted, and by the presence of loadstone the iron moves and attracts the loadstone itself, and by mutual forces a concurrency is made towards unity, which is commonly called attraction of the iron. But those formal forces pass out and are united to one another by meeting together; a force also, when conceived in the iron, begins to flow out without delay. But Julius Scaliger, who by other examples contends that this theory is absurd, makes in his 344th Exercise a great mistake. For the virtues of primary bodies are not to be compared with bodies formed from and mixed with them. He would now have been able (had he been still alive) to discern the nature of effused forms in the chapter on forms effused by spherical magneticks. But if iron is injured somewhat by rust, it is affected either only slightly or not at all by the stone. For the metal is spoiled when eaten away and deformed by external injuries or by lapse of time (just as has been said about the loadstone), and it loses its prime qualities which are conjoined to its form; or, being worn out by age, retains them in a languid and weak condition; indeed it cannot be properly re-formed, when it has been corrupted. But a powerful and fresh loadstone attracts sound and clean pieces of iron, and those pieces of iron (when they have conceived strength) have a powerful attraction for other iron wires and iron nails, not only one at a time, but even successively one behind another, three, four or five, end to end, sticking and hanging in order like a chain. The loadstone, however, would not attract the last one following in such a row, if there were no nails between. Drawing of nails by loadstone. A loadstone placed as at A draws a nail or a bar B; similarly behind B it draws C; and after C, D. But the nails B and C being removed, the loadstone A, if it remain at the same distance, does not raise the nail D into the air. This occurs for this reason: because in the case of a continuous row of nails the presence of the loadstone A, besides its own powers, raises the magnetick natures of the iron works B and C, and makes them, as it were, forces auxiliary to itself. But B and C, like a continuous magnetical body, extend as far asD