45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 



417 



FIG. 2409. 



FIG. 2408. 



2405 Metal Roller, with. Glass Handle and a roll of Tin Foil, mounted upon an 



Insulating Stand, to show the effect of an expansion of surface in reducing 

 the intensity of electrictity whilst the absolute quantity remains the same 

 (tig. 2405) 1 12 6 



2406 Electrometer, Coulomb's Torsion. This instrument measures very minute 



quantities of electricity, and with careful manipulation will give accurate 

 values of the attractive and repulsive force of free electricity communicated 

 to any body of known area . . . , . . . .330 



2407 Henly's Universal Discharger, with press and table, for deflagrating the 



metals by electricity, or exposing various substances to electrical action. 



1 12 6 



2408 Ditto, with Carbon Forceps, &c., adapted for Frictional or Voltaic electricity 



(fig. 2408) 220 



FIG. 2412. 



FIG. 2425. 



FIG. 2413. FIG. 2414. 



FIG. 2411, 



2409 Cuthbertson's Self-acting Balance or Steelyard Discharger (fig. 2409), for 

 indicating the force or strength of the discharge from an electric battery 

 by the position of the shifting weight on the graduated balance arm 2 15 6 



2 E 



