Dewars Method of producing High Vacua. 



511 



attained is ten times as great as that reached in the experi- 

 ments in which the apparatus was first of all exhausted by 













Fig. 



4. 











300 













































X 





















200 























) 

























x 



















100 



90 

 80 



70 





> 











































x 































































3 

















60 











































fc SQ 



^ 40 































































§ 











* 













3 30 



































c 











20 













X 























t 























X 



c 







10 



. 













—*— 







4 5 6 



T/ME JN M/A/UTES. 



Hate of Absorption of Air by Charcoal (April 21st). 



means o£ the Fleuss pump. The latter result has an im- 

 portant practical application, for it shows that it* we desire 

 to obtain the best possible vacuum in any vessel, the vessel 



