MAGNETO-ELECTRIC INSTRUMENTS. 49 



are represented connected, the one with a handle for the 

 hand, and the other an insulated conductor for applying to 

 any part of the body, by taking hold of the smaller part. 

 This instrument is packed, and has the same apparatus as 

 the preceding ones. Price, $15.00. 



Fig. 471. 



31C, 



New Portable Magneto- Electrical Machine for Medical 

 Purposes. (Fig. 471, as above.) The machine consists of 

 a double coil or helix of coarse copper wire, insulated, over 

 which is wound about 1000 feet of fine insulated copper 

 wire, in the interior of which is placed a bundle of soft iron 

 wires ; and which, when the machine is in operation, become 

 powerful magnets, and regulate the strength of the power 

 according to the extent they are placed in. At one end of 

 the machine (placed sometimes at the side), is an electro- 

 magnet, formed of soft iron, and bent in the form of an U, 

 and wound with two coils of covered copper wire, one end 

 of which is soldered to the magnet, and the other commu- 

 nicated with the coarse helix. To one end, or pole, of the 

 electro-magnet is fastened a spring with a small hammer at 

 one end, and just over the pole of the electro-magnet, and 

 through which spring the power of the battery flows ; from 

 the point of a screw supported on two brass pillars over the 

 middle of the spring (which screw can be moved to the 

 proper distance, to cause the vibrations to continue with the 

 best effect), the current from the battery is carried through 

 the helix, spring, and electro-magnet, by connecting wires 

 fastened in the brass cups, with binding screws at the side 

 of the machine. The fine wires are connected with cups at 

 the end of the machine, and in which are secured wires con- 

 necting with handles, or other conductors, for communicating 

 the effect. 



