45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 



457 



Each. 

 a. 



2780* Sponge Directors for the hands (fig. c) from, per pair 

 Ditto ditto Flat, large surface (fig. F) 

 Shock Handles, plain tubes and wires . . . 

 Curved and Bent Directors (or Rheophores), for the 



internal application of Electricity (figs. A & B) . 

 Flat and Curved Surface Director (figs. D & E) . 



FIG. 2781. 



2781 . Faraday's Wire Brush Directors with wood handles 

 (fig. 2781) . . 



Each. 

 a. d. 



046 



08 

 02 



10 6 

 056 076 



056 



FIG. 2782. 



2782~Pocket Medical Induction Coil (fig. 2782). In this apparatus the electro- 

 motor used is Pile Marie Davy, a voltaic battery having bi-sulphate of 

 mercury and carbon electrodes. The cell of this battery is made of vulcanite 

 in the form of a tray about If -inch square, and by 1-inch deep ; into this 

 tray is placed a slab of graphite, and above it a piece of zinc. Metal fittings 

 are attached to the cell to connect the elements to the coil. To charge the 

 battery, a small quantity of Bi-Sulphate of Mercury is placed on the Carbon, 

 which is to be saturated with water, and then have the zinc plate placed 

 upon it, observing that the zinc does not in any way touch the carbon. 

 The battery will now be in action, and the vibrating contact break should 

 be adjusted until steady vibrations are obtained. At the side of the box 

 will be found metallic fittings, by which shock handles or directors are to be 

 connected, and the current of electricity conveyed to any part of the person 

 to be operated upon. The strength of the current is regulated by a brass 

 tube, covering the bundle of iron wire in the centre of the coil. When 

 this brass tube entirely covers the iron wire, the action of the coil is very 

 feeble, but when it is fully drawn out, and the bundle quite uncovered, the 

 maximum amount of power is obtained. 



