4 8 4 



Further Experiments 



[Oclober, 



letters are the same in each illustration. A Bis a ma- 

 hogany board, 36 inches long by gj inches wide, and 1 inch 

 thick. It is suspended at the end, b, by a spring balance, c, 



Fig. 2. 



furnished with an automatic register, D. The balance is 

 suspended from a very firm tripod support, E. 



The following piece of apparatus is not shown in the 

 figures. To the moving index, o, of the spring balance, a 



Fig. 3. 



fine steel point is soldered, projecting horizontally outwards. 

 In front of the balance, and firmly fastened to it, is a 



