TROWBRIDGE. — HIGH ELECTROMOTIVE PORGBi 20 
of the house, and several of those who turned most <|iiickly saw slow moving hall 
discharges just outside the window. Oik* of those with whom I talked, a trained 
scientist, was sitting with his back partly turned, and saw only one ball of fire, k like 
a glowing coal'; but others said that it had been preceded l>y one rather larger* 
perhaps as large as a baseball. When he first saw the second ball, it was three or 
four feet from the ground, and was falling obliquely, as though it had rolled off the 
roof of a low ell near by, and its velocity was only r lew feet per ootid, — certainly 
not enough to leave a streak on his retina, as he noticed at the time. We * arched 
that night, and again carefully the next day, for traces of these discharges in the 
ground, but could find none. Whether they were independent discharges from th< 
main cloud, or were secondary effect, due to the electrification of the wet roof, I do 
not know. At any rate, they were not immediately connected with either of the 
three main discharges, for two oi' these went to obvious grounds, .-is lias been indi- 
cated; and the telephone wires, which carried off the third, were nowhere near the 
part of the house where these balls were seen." 
In long discharges of lightning these explosions directed at varied angles, could 
give rise to sound waves, which, starting practically at the same instant, nevertheless, 
by different angles and degrees of reflection, could arrive at the ear of the listener at 
considerable intervals, and produce the rolling of thunder. 
What, then, are the conclusions that can be drawn from the for< >ing manifesta 
tions of electric discharges which can be produced by a large number of storage cells ? 
The first fact which impresses one is the importance of the consideration of amperage 
as well as electromotive force. Throughout scientific literature, and in popular con- 
ception, electromotive force has received the chief consideration in discussing the 
phenomena of lightning. Experiments in laboratories have been conducted with 
ectrical machines which are generally incapable of affording much current. 
i's experiment with the aid of a kite illustrates an underestimate of the c 
lio-htnin^ discharge. Even to day no one would think of repealing Frank! 
I"' rank 
brated experiment, largely from a dread of voltage, but with littl conception of the 
possibility of danger from small voltage and large current. We are beginning to 
that 500 volts, accompanied by a current of from 10 

fficient to destroy human life. One compartment of the storage battery which I 
described 
affording something over S00 
uited through the body of the janitor of the laboratory, was sufficient 
knock him senselesf- 
The most powerful electric discharge which we can produce by modern appliances 
