Fig. 41—Showing how the Ball, Comb, etc., are mounted on the Glass Rod.
Make two forks as shown in Figure 42 out of brass rod, three-sixteenths of an inch in diameter and solder brass balls at the ends. The forks are eleven inches long.
A number of small holes must be bored in the "prongs" and pins made by cutting ordinary dressmakers’ pins in half and soldering them in place. These pins, mounted on the forks, form the combs or collectors.
Bore a horizontal hole through each of the brass rods on the top of the glass rods and pass the shanks of the forks through and solder them in place.
One of the shanks may be provided with a discharge ball at the end as shown by D B in Figure 44. The other is provided with a hard rubber handle made from a piece of rod. Bore a three-eighths hole directly in the top of each brass ball to receive the quadrant rods forming the spark-gap.
Fig. 42.—A Comb or Collector.
The quadrant rods extend over the top of the plates and are three-eighths of an inch in diameter. They are loose in the tops of the balls so that they may be moved about or removed entirely.
A small brass ball three-quarters of an inch in diameter should be soldered to the top of one of the quadrant rods and a similar ball two inches in diameter to the other.