DESCRIPTION OF A ROTATORY MULTIPLIER. 345 



pins proceeding from F come in contact with the globules situated at 

 G, and when E returns to its original starting point. It follows that 

 by a repetition of the process the galvanic action is sustained. The 

 phenomenon is as well illustrated by employing the single needle, N, 

 N, as by two, but the most pleasing and energetic effect is produced 

 by the crossed needles. In this simple form the spindle on which the 

 needle rests and revolves is represented at S ; the pins at P, P. Each 

 coil, consisting of copper bell wire, is about thirty feet in length, and 

 is contained in the groove C. The frame of the multiplier is con- 

 structed of mahogany and is levelled by the milled headed screws, 

 on the ends of which it is supported. 



