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. I do 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, was very feeble. 



29. I have shown, in the second number of my contributions, 

 that if the body be introduced into a circuit 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- 

 rent 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- 

 tor 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. 



