to Electricity and Magnetism. 559 



venient expression of Dr. Hare) that fifteen persons joining 

 hands and standing on the ground, received the shock at 

 once, when the first person of the series touched the wire. 

 A Leyden jar being grasped in the hand by the outer coating, 

 and the knob presented to the wire, a severe shock was re- 

 ceived, as if by a perforation of the glass, but which was found 

 to be the result of the sudden and intense induction. 



125. These effects were evidently not due to the accumu- 

 lated intensity at the extremities of the wire, on the prin- 

 ciples of ordinary electrical distribution, since the knuckle 

 required to be brought within about a quarter of an inch be- 

 fore the spark could be received. It was not alone the quan- 

 tity, since the experiments of Wilson prove that the same 

 effect is not produced with an equal amount of electricity on 

 the surface of a large conductor. It appears evidently there- 

 fore a case of the induction of an electrical current on itself. 

 The wire is charged with a considerable quantity of feeble 

 electricity, which passes off in the form of a current along its 

 whole length, and thus the induction takes place at the end of 

 the discharge, as in the case of a long wire transmitting a 

 current of galvanism. 



126. It is well known that the discharge from an electrical 

 battery possesses great divellent powers ; that it entirely se- 

 parates, in many instances, the particles of the body through 

 which it passes. This force acts, in part, at least, in the di- 

 rection of the line of the discharge, and appears to be ana- 

 logous to the repulsive action discovered by Ampere, in the 

 consecutive parts of the same galvanic current. To illustrate 

 this, paste on a piece of glass a narrow slip of tinfoil, 

 cut it through at several points, and loosen the ends from 

 the glass at the places so cut. Pass a discharge through 

 the tinfoil from about nine half-gallon jars ; the ends, at each 

 separation, will be thrown up, and sometimes bent entirely 

 back, as if by the action of a strong repulsive force, between 

 them. This will be under- 

 stood by a reference to fig. 14 ; 

 the ends are shown bent back 

 at a, a, a, a. In the popular 

 experiment of the pierced 

 card, the bur on each side 

 appears to be due to an ac- b glass plate; a, a, a, a, openings 

 tion of the same kind. ^" tinfoil. 



127. It now appears probable, from the facts given in pa- 

 ragraphs 119 and 120, that the table in paragraph 92 is only 

 an approximation to the truth, and that each current from 



