Tesla Coil - Secondary Winding Tips

[89.] — TESLA COIL. — You will get better results by using a greater number of turns on an increased length of core. Of course, if you insulate every layer carefully, you may wind on several layers, both of primary and secondary;" and, in order to prevent the insulation giving way, it would be better to stand the transformer bodily in an earthen vessel containing resinous paraffin oil of such a consistency that it will flow in between the layers of wire.
Arthur E. R. Bottone.