Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . nd not a consequence of the flow ofthe current below the position of the handle. Thedifference in the intensity of the shock in the twoarms, described in 480, may be observed wiih thisinstrument. 501. Compound Magnet and Electrotome.—InFig. 183 a double helix is seen attached to the baseboard by two brass bands. It is placed in a horizon-tal position, and within it a bundle of soft iron wiresis permanently fixed. There are two screw-cups forthe batter
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . nd not a consequence of the flow ofthe current below the position of the handle. Thedifference in the intensity of the shock in the twoarms, described in 480, may be observed wiih thisinstrument. 501. Compound Magnet and Electrotome.—InFig. 183 a double helix is seen attached to the baseboard by two brass bands. It is placed in a horizon-tal position, and within it a bundle of soft iron wiresis permanently fixed. There are two screw-cups forthe battery connections at one end of the stand; oneof these is connected with the band which sustainsthe glass mercury cup, C. To the second screv/-cup is soldered one end of the coarse wire coil, theother extremity of which is connected with the bandupon which the brass cup, B, also intended to holdmercury, is fixed. A bent wire, W, moving on ahorizontal axis, dips its ends into the two mercury COMPOUND MAGNET, &,C. 305 cups. On the opposite side of the axis is attached acurved iron rod, R, the lower extremity of which Jiff. approaches nearly the end of the enclosed bundle ofiron wires. 502. When the connections are made with thebattery, the current traverses the w^ire, W, and theinner helix, causing the iron wires to become-mag-netic. They now attract the end of the iron rod,R; the motion of the rod raises the bent wireout of the mercury in the cup C, and breaks thecircuit. This destroys the magnetism of the ironwires, and R is no longer attracted. The wire, W,then falls back by its own weight, and the circuitis renewed. A thin slip of brass is brazed to theend of R, to prevent it from being retained by theelectro-magnet after the rupture of the circuit. 503. In this manner a rapid vibration of the wireis produced, and brilliant sparks and deflagration ofthe mercury take place in the cup C. The proper 26* 306 DAVISS MANUAL. balance of the vibrating apparatus is insured bythe b
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
