556 



Professor Sir James Dewar 



[Jan. 22, 



diffusing in or coming from the stopcock. The vohune is kept small 

 by using tubing of about 2 mm. bore. By this means the diffused 

 pressure attains in a very short time a sufficient value to allow a 

 discharge to pass. 



-B 



Plate 8. 



The apparatus being highly exhausted, as shown by the absence of 

 any discharge when the induction coil is put on, the naked flame of 

 the Meker burner is applied to the platinum tube. Within a very few 

 seconds of closing off the charcoal stopcock a lilac-coloured discharge 



