Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . g as the tube, and their ends are madeto extend a little beyond one of its extremities. DOUBLE HELIX, &C. 301 When the helix is connected with the battery, po-larity is induced in the wires in the same directionas in the iron tube, and they are repelled until abouthalf of their length has passed out of the tube. Ifthe circuit is broken at this instant, the momentumwhich they have acquired causes them to be pro-jected to some distance. In this case, th
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . g as the tube, and their ends are madeto extend a little beyond one of its extremities. DOUBLE HELIX, &C. 301 When the helix is connected with the battery, po-larity is induced in the wires in the same directionas in the iron tube, and they are repelled until abouthalf of their length has passed out of the tube. Ifthe circuit is broken at this instant, the momentumwhich they have acquired causes them to be pro-jected to some distance. In this case, the repulsionoverpowers the axial force, which tends to draw thewires within the coil. The action is strongest whenthe helix surrounds that end of the tube from whichthey are projected. 496. Double Helix and Vibrating Electro-tome. — The instrument represented in Fig. 182 isone of the most convenient for the medical applica-tion of electricity. It is provided with a self-actinginterruptor, by which shocks can be given with ex-treme rapidity. The double helix is secured to thebase board, in a horizontal position, by two brass Fig. bands. The helices are insulated from each other,but are not separable. A bundle of iron wires isshown in the cut, within the inner helix. This can26 302 DAVISS MANUAL. be removed at pleasure. The vibrating electrotome,which is fixed on the stand, is of the same construc-tion as that represented in Fig. 176, except that thecoil surrounding the electro-magnet, M, is the electrotome are two screw-cups for batteryconnections. When the battery is applied, as shownin the cut, the current traverses in succession thecoarse wire helix and the coil of the electro-magnet is instantly charged, and attractsits armature, causing the circuit to be broken in themanner described in 456. At the other extremityof the base board are the screw-cups belonging tothe fine wire helix. With these the handles forshocks are connected. With all
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
