COIL MACHINES. 61 



attract a small piece of iron placed directly above them. This 

 iron is attached to a spring, (A,) so contrived, that the attraction 

 at once and completely cuts off contact with the battery. Two 

 effects are thus produced. The circulation of the electric current 

 through the primary coil gives rise by induction to a current of 

 electricity in the secondary coil, which is also considerably in- 

 creased by the reflex wave of electricity set in motion by the 

 demagnetising of the iron wires. The electricity thus generated 

 from these combined sources produces all the physiological effects 

 required, giving rise to strong shocks. But the moment the iron 

 is demagnetized, the spring A falls back to its place, and connec- 

 tion with the battery is again established, the wires are once 

 again rendered magnetic, and the same effects follow ; the rapi- 

 dity, indeed, with which the instrument acts is almost incredible. 

 In the foregoing figure, E, E, are the directors, applicable for 

 the mere transmission of shocks through the body generally ; 

 they are intended to be grasped in the hand of the patient. 

 When, however, it is required to transmit the shocks through any 

 affected limb, or to confine them to any organ, the sponge direc- 

 tors, represented above them in the same figure, must be resorted 

 to. They consist of metallic tubes, fitted with insulating handles 

 to protect the operator while administering the shocks. Into the 

 extremities of the metallic tubes pieces of sponge are to be placed, 

 and they are retained in their places by means of sliding rings, 

 with which the tubes themselves are furnished. Close to the 

 handles are binding screws, into which are to be fitted the con 

 ducting wires from the secondary coil of the machine. When 

 required for use, the sponges are to be well moistened with some 

 liquid, so as to increase the conducting power ; vinegar and water 

 is generally used, as being at hand. The sponge directors are 

 equally applicable for the administration of Galvanic Electricity 

 immediately from the battery. 



In the management of the Electro-magnetic coil, it is neces- 

 sary always to observe that the spring attached to the ball A 

 touches the screw C ; at the same time it must not be pressed 

 down so tight as to cause the ball to touch the iron wires in the 

 axis of the coil. According to the power required, the directors 



