414 



NEGKETTI AND ZAMBEA, HOLBORN VIADUCT, B.C., 



FIG. 2390. 



FIG. 2391. 



2390 Voss Electrical Machine is an improved form of Holtz' Machine, mounted 



on a polished Mahogany frame and base. This machine can be used in 

 almost any atmospheric condition, and under favourable circumstances 

 the length of spark obtainable from it is more than two-thirds that of 

 the diameter of the larger Glass Plate, with an exceedingly small amount 

 of manual labour. 



The excitement of the Yoss Machine is produced by holding against the G-lass 

 Plate a flat piece of Yulcanite which has been previously electrically excited 

 by rubbing it upon woollen cloth or cat's fur (fig. 2390) . price 4 10 



2391 Piche's Electro-Static Induction Machine, is a modified arrangement of 



Holtz's machine. It is composed of a circular plate of Vulcanite, in front 

 of which are placed two collecting forks in metallic connection with two 

 brass rods mounted on jointed insulated supports; these rods are so 

 contrived that they can be moved in any direction, or the terminal balls 

 brought close together. On one side and at a small distance belr'nd the 

 revolving plate is placed a flat oblong plate also of Vulcanite, termed 

 the Induction Plate, 



To put this machine in action the Induction Plate is withdrawn from its groove 

 on the base of the stand, and excited by rubbing it briskly with a cat skin or a 

 woollen cloth (Flannel), and quickly replaced in the groove, then upon rotating the 

 circular Yulcanite plate by the handle and multiplying wheels, it will be found 

 that one fork or comb will collect Positive, and the other Negative Electricity. 



Price of Piche's Machine as fig. 2391, with 18-inch Yulcanite Plate 12 12 



2391* Wimshurst's High Tension Electric Machines. An improved form of Nos. 

 2390 and 2391. These machines can be used in place of Induction Coils 

 for illuminating Yacuum Tubes, Spectroscopic Experiments, &c. They 

 are made of three sizes, including a packing case 



16-inch plate, 6; 12-inch, 5; 8-inch, 2 2s. 



