On Electro-Dynamic Induction. 127 
it appears to me that this result might have been predicted with- 
out reference to any theory. There was no reason to suppose 
the induction at the beginning would be different in its nature 
from that at the ending, and therefore the series which would be 
produced from the former might be immediately inferred from 
that belonging to the latter, by recollecting that the direction 
of the induction at the beginning should be opposite to that at 
the ending. Ido not wish it to be supposed, however, from this 
remark, that I had, myself, drawn any inference from my exper- 
iments as to the alternations of currents which might be produ-" 
ced by the beginning induction; the truth is, that this action 
was so feeble with the arrangement of apparatus I employed, that 
I supposed it could not produce a series of currents of the diffe- 
rent orders. 
28. In the course of the experiments given in this section, I 
have found that a shock can be produced without using a coil, by 
arranging about ten elements of the battery in the form of a cir- 
cle, and placing the helix within this. ‘The shock was felt in the 
hands at the moment of closing the circuit, but the effect at open-— 
ing the same was scarcely perceptible through the tongue. An 
attempt was also made to get indications of induction by placing © 
the helix within a circle of dilute acid, connected with a battery 
instead of a coil, but the effect, if any, Ha very feeble. i 
29. I have shown, in the second number of my contributions 
that if the body be introduced into a cireuit with a battery of one 
hundred and twenty elements, without a coil, a thrilling sensa- 
» tion will be felt during the continuance of the current, and a 
Shock will be experienced at the moment of interrupting the cur- 
tent by breaking the circuit at any point. ‘This result is evidently 
due to the induction of a secondary current in the battery itself, 
and on this principle the remarkable physiological effects produ- 
ced by Dr. Ure, on the body of a malefactor, may be explained. 
The body, in these experiments, was made to form a part of the 
circuit, with a compound galvanic apparatus, in which a series of 
Interruptions was rapidly made by drawing the end of a conduc- 
lor over the edges of the plates of the battery. By this opera- 
tion a series of induced currents must have been produced in the 
battery itself, the intensity of which was greater than that of the 
Primary current. = 
