Nikola Tesla Books
INDUCTION COIL OUTFITS 61 The silk is tough and strong and the worker will be enabled to preserve the solidity of his bundle as he removes the binding wires and replaces them with the silk wrapping. When the entire core is covered, the final turn of ribbon may be held with shellac and a few turns of thread taken over the end to insure permanency. The whole core, with its wrapping of ribbon, is then to be suspended in a trough filled with thin shellac. A submersion of an hour will have served largely to fill the interstices between wires and to soak the ribbon thoroughly. The core is then hung up to drain and dry. The latter operation will take the best part of 24 hours. When the shellac is hard, the core will be almost as solid as if it were of one piece of iron, and it is then ready for winding. The primary is in two layers. The end of a spool of No. 14 D.C.C. magnet wire is placed under a loop of the silk ribbon on the core and the winding started by turning the core with both hands. The second turn of wire grips the ribbon loop and thus secures the starting turn. The first turn should start at a distance of one inch from the end of the core and the first layer ends at this distance from the other end. The second layer of wire is wound upon the first, with a layer of empire cloth between. The finishing end of the primary winding is secured with a loop of ribbon, the ends of the loop being pulled tight after the ribbon has been covered by the last three or four turns of the winding. The entire primary is then to be wound with silk ribbon in exactly the same manner as the core and the end where the leads come out should be wound with a number of turns of strong thread to prevent the possibility of the starting and finishing turns coming loose. The entire core and primary is now to be immersed in a compound of equal parts of beeswax and rosin, melted in a double boiler to prevent scorching. An immersion of an hour or
