the Separation of the Isotopes of Mercury. 35 



(a) The experimental method. 

 In separating the mercury isotopes the following arrange- 

 ment was used :- — In the space H between the outer and 



Est. 1. 



inner flask of the Dewar vessel (fig. 1) about 300 c. cm. 

 mercury were placed, H thoroughly evacuated by means of 

 a Vollmer pump which was connected at B, and the inner 



D2 



