The wires, C and D, coming from the secondary coil ([§ 138]) are in connection with Y and Z, to which are connected the wires leading from the handles ([App. 101]) held by the person receiving the shock.
142. To use the coil, arrange as explained. Let your friend hold the handles ([App. 101]) while you scrape the end of P back and forth along the row of nails. For those who cannot stand much of a shock, use a regulator ([App. 103]).
143. Induction Coil. Fig. 76. In case you wish to make the interrupter as a separate piece of apparatus, as [App. 104], this arrangement will be found good. The base is 5 × 4 × ⅞ in. The coil is explained in [App. 96], and the methods of holding it to the base are given in [App. 97]. The binding-posts are like [App. 46].
Fig. 76.
The Connections. We shall suppose that you have the interrupter of [App. 104], Fig. 81. The ends of the primary coil ([§ 137]) are fastened under the screws of X and W, and those of the secondary coil to Y and Z. Connect one battery wire with X and the other battery wire to the interrupter at S, Fig. 81. Fasten the end of a stout wire to W, and leave the other end free to scrape along on the nails, Q, of the interrupter. This will then open and close the primary circuit. The handles ([App. 101]) are connected with Y and Z, as explained in [App. 97]. Use the battery of [App. 3] or [4].
144. Induction Coil. Fig. 77. If you wish to fasten your coil in an upright position the apparatus will look like Fig. 77. The base may be 5 × 4 × ⅞ in. The binding-posts are like [App. 46]. The coil is made as explained in [App. 96]; but to have all the ends of the coils come out at the bottom, as shown, an even number of layers of wire will be necessary. It will be just as well to have an odd number of layers as before, and to bring the wire ends down the side of the coil. The coil is fastened to the base with screws, S, passing through a tin strip, T, which has a hole punched for the bolt. T is squeezed between the regular nut on the bolt and an extra one on the underside of it. See Fig. 61 for suggestion of another method of holding bolts upright. The connections should be made with an outside interrupter, battery, and handles, as explained in [App. 98].