Nipher—Gravitation and Electrical Action. 165 
have no attraction for each other, although both would 
be attracted by the earth, even if it had the same poten- 
tial. The attraction of the earth for a gram of lead 
would then be by (1) 
A = 981 — 0.000,000,000,006. 
The acceleration of a falling body would be practically 
unchanged, and would not depend upon the density of the 
matter of which it is composed, as it would apparently 
be under the conditions assumed in Eq. (1). 
Raindrops falling through an overcharged® thunder- 
cloud would repel each other. After the diverging 
branches of a flash of lightning have penetrated the cloud 
a new condition has arisen. Overcharged drops of water 
along the lines of the intricate system of branches of the 
discharge, have delivered their overcharge to the cloud 
at the other end of the long flash. These drops are inti- 
mately commingled with drops which are outside of the 
drainage lines. The value of V for these two groups of 
drops now have opposite signs. The final term in equa- 
tion (1) then becomes positive, as applied to these 
groups, and it is much greater than the gravitation term. 
These drops coalesce as they fall to earth and a brief 
. dash of unusually large drops of rain follows.* 
In former papers above referred to, an experimental 
study of explosive effects due to a discharge from a large 
condenser through a small lead wire was discussed. The 
wire was sealed within a glass tube filled with coal oil. 
This work has been continued in a modified form. Four 
quarter ampére fuse-wires of lead were placed in multi- 
ple across a gap, five centimeters in length in a line lead- 
ing from either terminal of an influence machine to a 
Te eee Sas 
* The word overcharged, or super-charged, was in common use more 
‘han a century ago, when the one-fluid theory was in general favor. 
*See Nipher. A Flash of Lightning. Popular Science Monthly. 
: 76 
— Experimental Studies in Electricity and Magnetism. Pp. 
