454 



NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 



FIG. 2767. 



FIG. 2762, 



2763 Glass Tube for similar experiments, fitted -with a 



Stop-Cock, various lengths (see page 438) . from 



2764 Ditto ditto of Uranium glass . . from 



2765 Eudiometer, for use with Inductorium . 



2766 Uranium Glass Vessel, for showing Fluorescence from 



2767 Whirling Apparatus for Gassiot's Star, for large sized 



Vacuum tubes (fig. 2767) 



2767* Revolving Colour Disc, for use with No. 2767, exhibiting 

 white light, and proving that the induction spark is 

 not continuous .... 



Each. 

 s. d. 



220 

 440 

 076 

 10 6 



4 12 



10 6 



FIG. 27 6 J. 



2768 Wheatstone's Rheostat, for adjusting and regulating 



an electric current so as to obtain any constant 

 degree of force ........ 



2769 Wheatstone's Rheostat, for ascertaining the amount of 



resistance offered by various lengths of wire to a 

 given current of electricity (fig. 2769) 



2770 Wheatstone's Apparatus, for determining the 



Differential Resistance of various metal wires, &c. &c. 



440 



550 

 2 10 



