Tesla Coil for 2-Inch Spark Coil

(974) R. Conover, New York, N. Y., inquires of "The Oracle":

Q. 1. For data on a Tesla coil suitable for use on a 2-inch spark coil as an exciter.

A. 1. The ordinary Tesla coil, especially designed to work with a spark up to 2 inches on the primary side will do, and is briefly described as follows. The primary should consist of 14 turns No. 10 solid, rubber-covered copper wire in one layer on a spool 4 1/2 inches in diameter, while the secondary consists of a coil 2 3/4 inches in diameter and 12 inches long, wound its full length with a layer No. 28 enamel wire. This size of Tesla coil can be furnished by the leading companies who advertise in our magazine. It is best to use two one- pint Leyden jars connected in parallel or a one-quart Leyden jar. The construction for a glass plate condenser for the above Tesla coil is as follows: Procure five glass plates 6x7x1/16" and four pieces of tin-foil 5x6 inches. The tin-foil should be placed between the five plates so that two ends of the tin-foil protrude from the sides of the glass. The size of the spark obtained from the above Tesla coil will be about 3/4 to 1 inch and can be taken thru the body without any harm.