New Form of Influence-Machine* 265 



at the circumference than at the centre of the disk. Upon 

 each slip is a brush, A, and also an inductor, the brush and 





A, A. Brushes connected metallically to the inductors. 



B, B. Collecting-brushes connected with terminals. 



C, C. Brushes connected with the neutralizing circuit, 



the inductor being metallically connected ; the brushes are 

 made of fine wire, and touch very lightly on the inner sur- 

 faces of the disks. The glass slips slide into place by means 

 of suitable grooves at their top and bottom ends ; they may 

 be removed and replaced readily at pleasure. 



The essential parts are fitted together within a glass case, 

 and in all respects the machine is so constructed as to be 

 useful for experimental work. The limited size of the case 

 causes the insulating distances between part and part to be 

 small, hence the length of the sparks is reduced. All the 

 surfaces are coated with shellac, and when the brushes are 

 new and in proper condition the machine is self- exciting. 



The charges are not subject to reversal when the terminals 

 are opened beyond the striking distance, for then the whole 

 of the induced charges pass by way of the neutralizing 

 brushes C, 0. Another feature is that the neutralizing cur- 

 rent may also be broken without reducing the excitement, 



Phil. Mag. S. 5. Vol. 36. No. 220. Sept. 1893. T 



