Tesla Apparatus

To Mr. Bottone. — This is practically a transformer, which can be used either as a "step up" or step down," according to whether you connect the primary or secondary to the terminals of your spark coil. It is necessary, however, to insulate the winding much more carefully, and, having wound the primary on the iron core, insert it bodily in an ebonite tube, over which wind the secondary; then immerse the whole in a non-conducting vessel of boiled linseed oil. The iron core should be of soft iron wire, making a bundle of about 3/4 in. diameter and 8in. long, and wound with two layers of No. 14 guttapercha-covered wire. The secondary may consist of about thirty layers of No. 26 silk-covered wire. Full particulars and illustrations are given in S. R. Bottone's book, "Electrical Instrument Making."

Arthur E. R. Bottone.