Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . in front of themagnet, and to remain at restwhen the lamp is on the otherside. A stand to support the lampslides on the brass pillar, and isfixed at any required height bymeans of a binding screw. Thelamp should be placed in the po-sition represented in the cut, infront of the magnet, its north polebeing on the left. 203. When either of the junc-tions is in the flame, a current flowsfrom the German silver to thesilver, ascending by the heatedside of t
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . in front of themagnet, and to remain at restwhen the lamp is on the otherside. A stand to support the lampslides on the brass pillar, and isfixed at any required height bymeans of a binding screw. Thelamp should be placed in the po-sition represented in the cut, infront of the magnet, its north polebeing on the left. 203. When either of the junc-tions is in the flame, a current flowsfrom the German silver to thesilver, ascending by the heatedside of the arch, and descending by the other. Thatface which is presented towards the north pole ac-quires north polarity, and the other face south polar-ity. The influence of the magnet now causes thearch to turn half way round, so as to present itssouthern face to the north pole. This movementbrings the other junction into the flame; the po-larity of the arch is reversed, and it moves on asbefore. 204. If the lamp be placed in the correspondingposition on the other side of the magnet, the direc-tion of the current will be such that the southern. DOUBLE REVOLVING ARCH. 129 face of the arch will be presented towards the northpole. In this position the arch tends to remain,returning to it when moved to either side; andconsequently no revolution can be obtained. Careshould be taken not to allow the junction to remainso long in the flame as to melt the solder. 205. Double Thermo-Electric Revolving Arch.— In this instrument, two arches, a and b (Fig. 7S), are so mounted as torevolve between thepoles of a U-magnetfixed in a horizontalposition. The hori-zontal portion of thearch a is of Germansilver, and the upperpart of silver; while in 6, the lower portion is ofsilver, and the upper part of German silver, Asingle lamp is so placed as to heat both arches j thecurrent excited in each ascends on its right sideand descends on its left side, because the heat isapplied to the right junction of
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
