676 Scientific Proceedings, Royal Dublin Society. 



the battery-voltage or by increasing the dimensions of the machine, or, again, 

 by adopting Einstein's plan of combining the same principle more than once 

 in the same machine. However, as my own purpose was served by a voltage 

 of about 4000, I have not sought to extend the range further. 



I may add that I have had the machine in use for several months, and I 

 have found it most constant a,nd reliable in its action, provided only that the 

 ordinary precautions against dampness are taken, which precautions are 

 inseparable from most electrostatic apparatus. Under these conditions I have 

 been able to maintain a voltage of 4000 or 5000 constant to within 1 or 2 per 

 cent, for several hours, the charged system consisting principally of a leyden jar 

 of about 1000 cms. capacity, to which my other apparatus, of much smaller 

 capacity, could be connected as desired. 



