TROWBRIDGE. — HIGH ELECTROMOTIVE FOR( I . 197 
the novel of "Frankenstein" had been written in this century, the million s would 
undoubtedly have equipped her automaton with a storage battery. 
If a milliamperemeter is interposed between one terminal of the battery and one 
coating of the Leyden jar, the current rises to a definite value and remains stationary 
until the jar discharges. At the moment of discharge the reading of the smpere- 
suddenly, and then falls to its steady 
1. 
the resistance interposed in the circuit. The rise in nailing is evidently due to tb 
lished air resistance at the spark gap. The resistance of the spark is less than 
dimi 
ohm, or at least does not exceed two or three ohms. We can therefore form 
idea of the magnitude of the resistance of the air in the case <>f the silent dis- 
•-! 
charge, and indeed of the brush discha 
The resistance of the silent discharge estimated in this way, — that i^. by 
in resistance when the spark passes between pointed terminals 2 cm. apart 
f. 
difference of potential of 20,000 
of the interposed layer of air. It depend 
is a 
A-hat is usually taken as the electric strength 
5 upon the electric density which, in turn, 
direct function of the voltage and amperage of the battery. The apparent 
resistance of the silent 'discharge thus depends upon the energy of ionization, and the 
latter is so much the greater, the greater the coated surface of the battery and the 
voltage and charge. 
Tli 
OSCILLATION OR PTJLSATIOK OF THE CELL-. 
discharge from a large number of stora e cells, like that from a high 
5^ """- ■ n 
transformer giving a large amperage, is characterized by a sibilant flame < 
a difference of potential of 40,000 volts can be drawn out to more than tl 
When a photograph of such a discharge is examined, it is seen to have a br 
snark as a nucleus. On account of the flaming nature of the envelope of 
'y 
discharge it is difficult 
by means of 
I >>y 
.ploy 
two spark gape, and maintaining fixed the terminals in the 
gap, one can photo 
i the pulsations aero this ^ •. Photographs obtained 
of the phenomena at this gap observed in a revolving mirror showed verv 
pulsations or oscillations. 
I have described elsev 
for charging condensers in multiple and 
then discharging them in series. 1 Since writing this paper I have constructed 
o*"o 
pparat 
sure. 
of giving sparks seven feet in length in air at atmospheric pres- 
ffp to one million and a half volts the length of the discharge is clone.. 
XXXIII, No. 21, Juno, 1898. 
