ATTAINMENT OF VERY LOW TEMPERATURES. 



25 



original piston c and crosshead /. A hole i was bored in the top of the 

 cylinder so that the space mm filled with water automatically from the 

 tank in which the cylin- 

 der was immersed. If 

 now the cup-fiber dd 

 fitted the cylinder badly, ^ 

 only water could be 

 drawn into the latter 

 during the compression 

 of the gas. 



The whole arrange- 

 ment for the com.pres- 

 sion and circulation of 

 the hydrogen is shown 

 in fig. 8. The hydro- 

 gen is conveyed from the 

 gasometer, which is not 

 shown in the figure, by 

 a pipe CC, which com- 

 municates through a 

 stopcock and connecting 

 pipe with the low-pres- 

 sure intake of the com- 

 pressor A. The lique- 

 fying apparatus I have 

 described was designed 

 to work with about ten 

 cubic meters of gas per 

 hour. To deliver this 

 quantity of gas the com- 

 pressor must run at 360 

 revolutions per minute, 

 and requires about seven 

 horse-power to drive it. 



Water mixed with 

 about twenty percent of 

 glycerol and one percent 

 of caustic soda is drawn 

 into the compressor 

 from the reservoir R. 

 The jet of the glass 

 stopcock on R passes 



through a rubber cock in the neck of a small funnel which is connected 

 below with the small cock on the intake pipe by means of a piece of 

 rubber tube. 



