Mr. Spitspury on a Single Galvanic Combination. 83 
needle ¢,«,«. E is an ivory gradulated table supported by the 
pedestal G. F is one of the connecting cups containing mercury. 
The intention of the screw C is to regulate the height of the needle 
«, ¢, ¢, which otherwise might be difficult to accomplish. The mode 
of using this instrument is of course similar to that described by 
Professor Cumming. 
L2 
