1876.] The Newly-Discovered Force . 193 
afterwards found out, by a combination of accident with 
closer observation and a better knowledge of the conduCti- 
bility of the air and the body, that the force in this experi- 
ment was all the while passing not through the glass rod at 
all, but through the body of the person adjusting the wires, 
or through the air from between the surface of his hand and 
the terminal ; with one hand on one terminal and the other 
brought within a foot or more from the other terminal, the 
spark appeared. 
Mr. Edison suspeCts, and he may be right, that in certain 
barometric and hydroscopic states of the atmosphere the 
force may pass through long rods of glass ; but in the 
many experiments that I have made since the discovery of 
this error here noted, I have never been able to see the 
spark when any considerable length of glass or rubber or 
shellac was interposed between the terminals, excepting 
when there was at one or both of the terminals a large con- 
ducting surface. 
Phenomena of this kind suggest magnetism more than 
indudtive or dynamical electricity, but this force does not 
respond to the test of magnetism, the power to attract iron, 
and moreover exhibits phenomena that do not belong to 
magnetism. This force is attracted by iron and other metal 
as conductors, but it does not appear to attract iron. 
The points which favour the theory that this force, whether 
electrical or radiant, is yet something new to science, may 
be thus recapitulated 
1. It does not respond to any of the physical tests of elec- 
tricity, except the spark. 
2. It produces no perceptible or demonstrable physiolo- 
gical effects like electricity, save on the frog. 
3. It gives no evidence, in any of its phenomena, of po- 
larity. 
4. It passes through the air and other resistances by 
large surface at the terminals, even when the appa- 
ratus is not insulated. 
5. When connected with the earth or walls of the room 
it can yet be drawn off from the conductor. 
Any known form of electricity giving a spark like the spark 
of this force would respond to some of the physical tests of 
electricity ; would produce readily perceptible physiological 
effects ; and would in its phenomena suggest polarity, even if 
rapidly reversed. 
Again, the four faCts regarded by me as favouring the 
theory that this force is allied to electricity are, when severely 
analysed, not so convincing as they might at first appear. 
VOL. VI. (N.S.) 2 
