186 



Scientific Proceedings, Royal Dublin Society. 



The connexions of the oscillating circuit shown in the figure were slightly 

 modified in practice, a potential balancing device, similar to that described 

 in my previous paper,^ being employed so as to permit a sensitive galvano- 

 meter to be substituted for the milammefcer A, An ordinary B.T.H. 

 receiving valve was employed, and a negative potential of a few volts was- 

 found necessary in the grid circuit to obtain good oscillatory conditions. 

 In the preliminary experiments a coil of about 10'' cms. inductance was used. 



L. 



M. 



Z 



C. 



the portion L being usually about one-quarter of the whole. An air con- 

 denser, having a range of 100 to 1,200 micro-microfarads was used in the 

 course of these preliminary tests. I may mention that the currents in the 

 plate circuit varied from one-half to several milliamperes, and that it was con- 

 venient to employ an Ayrton-Mather universal shunt with the galvaiion;eter 

 to facilitate preliminary adjustments. 



One consideration is of importance in the working of the apparatus. 

 With a given adjustment of the inductances, it is found that there is a 



' loc. cit. 



