Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . re ; the direction of the rotationdepending upon that of the current. 167. Magnet revolving on its Axis. — The in-strument represented in Fig. 57 is designed to showj?:^^ 57, that the action be- tween the currentand the magnettakes place equal-ly well when themagnet itself formsthe conductor electricity. Thelower end, N, of themagnet, being point-ed, is supported onan agate at the bot-tom of a brass cup,connected under thebase-board vv^ith the
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . re ; the direction of the rotationdepending upon that of the current. 167. Magnet revolving on its Axis. — The in-strument represented in Fig. 57 is designed to showj?:^^ 57, that the action be- tween the currentand the magnettakes place equal-ly well when themagnet itself formsthe conductor electricity. Thelower end, N, of themagnet, being point-ed, is supported onan agate at the bot-tom of a brass cup,connected under thebase-board vv^ith the screvv--ciip C. The upper end,S, is hollowed out to receive the end of the wirefixed to the cup A; the brass arm supporting thiscup is insulated from the brass pillar by some non-conductor of electricity. To the middle of themagnet is fixed a small ivory cistern, for containingmercury, into v/hich dips the end of a wire, the cup B. Thus the magnet is supported withits north pole downwards, and is free to rotate roundits vertical axis. A little mercury should be put intoIhe cavity at S, and into the brass cup at N, and the. 106 DAVIS S MANUAL. ivoryCistern be filled sufficiently to establish a con-nection between the magnet and the wire attachedto B. When the cups A and B are connected withthe battery, the current will flow through the upperhalf of the magnet, causing it to rotate rapidly. Ifthe cups B and C form the connection, the currentwill traverse the lower half, equally producing revo-lution of the magnet. Now, connect A and C withthe battery, and no motion will result, because theelectricity passes through the whole length of the mag-net in such a manner that the tendency of one poleto rotate is counteracted by that of the other to movein the opposite direction. Connect B with one poleof the battery, and A and C both with the other magnet will now revolve; since the current as-cends in one half of its length and descends in the other. 168. Revol
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
