Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 145
ce 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… … 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…
