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The Newly ‘Discovered Force . 
[April, 
different forms of electricity their polarity, and you take 
all their practical usefulness in telegraphy, in electroplating, 
in signalling, in medicine, or in surgery. 
Conceivable Sources of Error . 
The presumption against the actual demonstration of the 
existence of a new force is very great, and can only be over- 
come by evidence of an overwhelming character. The 
experiments must be repeated with substantially similar 
results, at various times, and by different expert observers. 
When, however, the phenomena are admitted, and when it 
is admitted that they cannot be explained by laws of elec- 
tricity as known to experts in that branch of science, the 
burden of proof is shifted, and the presumption is against 
the claim that these phenomena represent some known phase 
of the electrical force. 
Mr. Edison and myself, and a number of physicists, who 
have thus far studied the subject, have made earnest and 
sustained efforts to prove that some known form of elec- 
tricity would account for all these phenomena. Four theories 
of electricity have occurred to us, and by all of them these 
phenomena have been tested. 
First. Creeping Electricity , which passes over the sides of 
the cells, and completes the circuit through the earth and 
air. This is the theory that would naturally occur to any 
physicist on first examining the phenomena. Besides the 
general faCt that this force does not respond to the ordinary 
tests of induced electricity, this theory is met by two faCts, 
either of which seems to be sufficient to overthrow it. 
1. The phenomena of the force appear just as well when 
the cells of the battery and the entire apparatus are most 
thoroughly insulated. In one case the insulation was so 
complete that when the entire apparatus on the insulating 
stands were charged by statical electricity, the charge was 
retained for a long time, so that sparks could be taken from 
it ; and yet the force appeared fully as strong as when there 
was no insulation. 
2. In order to complete the circuit, it would be necessary 
for the induced electricity to traverse immense distances in 
the air, and at the same time have sufficient strength to give 
a decided spark. This is inconceivable ; and, further, it is 
shown by direCt experiment that this force, though it can 
go through the air when the surfaces at the ends of the 
conductors are sufficiently large, yet only for a few inches 
or a few feet at most, and when the ends of the conductors 
