Nikola Tesla Books
218 HIGH FREQUENCY APPARATUS first one. The tape and line may then be brought up to the lug and finished off. The same process is repeated with the second bundle of wires to form a cable similar to the first. The only other adjuncts necessary for the simpler experiments with the transformer are two pairs of tongs or clamps to which the cables are fastened. In Fig 12 the reader will note a suggestion for a pair of tongs of suitable design, and if the worker is a fairly skilful patternmaker he can make a pattern from which a copper or bronze casting may be made. Failing in this, he may use a dismantled pair of iron tongs or gas pliers for the patterns, making such changes as may be necessary with the aid of a bit of hard wax. The illustration is just one-half the size of the finished tongs used in the author's outfit, and it will not be safe to use a lighter weight of copper as the tongs heat up pretty well after the current has been on a few minutes. The lug of the cable is fitted to the handle of the tong as shown in the illustration. Assuming that the transformer has been set up, the worker will be anxious to try it out. The tongs may be grasped with the bare hands as the voltage of the secondary is so low that practically no shock will be perceptible; however, if the performer's hands are tender or susceptible to perspiration, the handles of the tongs may be dipped in white lacquer which will be quite invisible when dry but which, at the same time, acts as an effective insulator. The tongs having been connected to the transformer secondary by means of the cables and the 60-cycle alternating current circuit through a 30-ampere fused switch, the performer may grasp a piece of 1/4-inch steel rod about two feet long in the jaws of the tongs and have an assistant turn on the primary current. The steel will quickly discolor and become gradually red and then white hot. At
