Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . supported on a tripod stand, with leveUing screws; the ends, C and D, of the wires being connected with the screw cups, A and B. i^>. 55. 1^1- Upright Galvanometer.— In this instrument, represented inFig. 55, both the coil of wire andthe needle are placed in a verticalposition, the north pole being madea little heavier, in order to keepthe magnet perpendicular. Whena current is passed through thecoil, the deflection is towards ahorizontal position.
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . supported on a tripod stand, with leveUing screws; the ends, C and D, of the wires being connected with the screw cups, A and B. i^>. 55. 1^1- Upright Galvanometer.— In this instrument, represented inFig. 55, both the coil of wire andthe needle are placed in a verticalposition, the north pole being madea little heavier, in order to keepthe magnet perpendicular. Whena current is passed through thecoil, the deflection is towards ahorizontal position. The needle ismade of large size, for the purposeof exhibiting the deflections beforean 102 r-AVIss MANUAL. 162. Galvanometer with Astatic Needle. —This instrument is represented in Fig. 39, in connec-tion with a thermo-electric pair. It is constructed ona small scale, in order to be delicate j and the needleis nearly astatic. The slight degree of directivetendency which the needle is allowed to retainbecomes the measure of the force of the electriccurrent, as the angle of deflection from the north andsouth line shows how far this resistance is instrument may be made so extremely delicatein its indications, that, if two fine wires, one of cop-per and one of zinc, are connected with it, and theirends slightly immersed in diluted acid, or even inwater, it will be very perceptibly afiected. Beforeproceeding to experiment with any galvanometer,it should be so placed that the direction of the coilmay coincide with that of the needle, as this isthe position of greatest sensibility. 163. The galvanometer is a measurer of what iscalled the quantity of electricity
Size: 1094px × 2284px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
