Page:Elementary Text-book of Physics (Anthony, 1897).djvu/314

300 charge on one plate is made to develop an indefinite quantity of electricity of high potential, is shown in Fig. 82. $$A_{1}$$ and $$A_{2}$$ are conducting plates, called inductors. In front of them two disks $$B_{1}$$ and $$B_{2},$$ called carriers, are mounted on an arm so as to turn about the axis $$E.$$ Projecting springs $$b_{1}$$ and $$b_{2}$$ attached to these disks are so fixed as to touch successively the pins $$D_{1}$$ and $$D_{2},$$ connected with the plates $$A_{1}$$ and $$A_{2},$$ and the pins $$C_{1}$$ and $$C_{2},$$ insulated from the plates, but joined to the prime conductors $$F_{1}$$ and $$F_{2}.$$

Suppose the prime conductors to be in contact and the carriers so placed that $$B_{1}$$ is between $$D_{1}$$ and $$C_{1},$$ and suppose the plate $$A_{1}$$ to be at a slightly higher potential than the rest of the machine. The carrier $$B_{1}$$ is then charged by induction. When the carriers are turned in the direction of the arrows, and the carrier $$B_{1}$$ makes contact with the pin $$C_{1}$$ it loses a part of its positive charge and the prime conductors become positively charged. At the same time the carrier $$B_{2}$$ becomes positively charged. As the carrier $$B_{2}$$ passes over the upper part of the plate $$A_{2},$$ the lower part of the plate $$A_{2}$$ is charged positively by induction. This positive charge is neutralized by the negative charge of the carrier $$B_{1},$$ when contact is made at $$D_{2}.$$ The plate $$A_{2}$$ is then negatively charged. The carrier $$B_{2}$$ at its contact at $$D_{1}$$ shares its positive charge with the plate $$A_{1}.$$ The carriers then return to the positions from which they started, and the difference of potential between the plates $$A_{1}$$ and $$A_{2}$$ is greater than it was at first. When, after sufficient repetition of this process, the difference of potential has become sufficiently great, the prime conductors may be separated, and the transfer of electricity between the points $$F_{1}$$ and $$F_{2}$$ then takes place through the air. Obviously the number of carriers may be increased, with a corresponding increase in the rapidity of