. Practical electricity in medicine and surgery. sbefore the magnet was ruptured. N Q ? /?;?? , ?</ -I 1 t- ? -/- 1 i nm? n ; ; n si 1G. • N S 12. N S It might seem that this was contrary to the law of the con-servation of energy, inasmuch as it might appear that energy iscreated by the process. A little reflection, however, shows usthat this is only apparently true, since the fragments of thebroken magnet are not themselves magnets until they are sepa-rated, and in the act of separating them we do an amount ofwork equal to that which they could do by attracting othermagnets. Lines of Magne
. Practical electricity in medicine and surgery. sbefore the magnet was ruptured. N Q ? /?;?? , ?</ -I 1 t- ? -/- 1 i nm? n ; ; n si 1G. • N S 12. N S It might seem that this was contrary to the law of the con-servation of energy, inasmuch as it might appear that energy iscreated by the process. A little reflection, however, shows usthat this is only apparently true, since the fragments of thebroken magnet are not themselves magnets until they are sepa-rated, and in the act of separating them we do an amount ofwork equal to that which they could do by attracting othermagnets. Lines of Magnetic Force.—In the explanation of electricalattractions and repulsions we made use of Faradays idea oflines of force. In the study of magnetism we shall find theconception of very much greater value, and shall at once realizehow materially it will aid us in the understanding of many mag-netic and electro-magnetic phenomena of the utmost importance. According to Faradays view every magnet is supposed to LINES OF MAGNETIC FORCE. 55. Fig. 43. send outward from itself lines of force into the surroundingregion. Starting from one pole, they go outward a certaindistance, and then, curving backward in a more or less regularmanner, they finally reach the opposite pole. The generaldirections of these lines of force for an ordinary bar magnetarc exhibited with sufficient accuracy in Fig. 43. Fig. 44shows the lines of force around the poles of a horse-shoemagnet. They can be easily obtained by dropping iron tilingson a piece of card-board held over the poles of the these circumstances thelittle particles of iron becomethemselves magnets, and direct themselves according to thedirection of the magnetic forceat the points they occupy. Byslightly tapping the card the par-ticles are shifted about and areenabled to group themselvesmore readily, which they do ina very regular manner. Thelines of force are, therefore, thedirections which a magnet wouldtake up, if freely suspended s
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectelectri, bookyear1890
