262 



LIQUEFACTIOM OF HYDROGEN AND HELIUM. 



of a jet of hydrogen containing visible liquid. This is reproduced in the 

 figure. A represents one of the hydrogen cylinders; B and C, vacuum 

 vessels containing carbonic acid under exhaustion and liquid air, 

 respectively ; D is the coil, G the pin-hole nozzle, and F the valve. By 

 means of this jet, liquid air can be quickly transformed into a hard 

 solid. It was shown that such a jet could be used to cool bodies below 

 the temperature that it is possible to reach by the use of liquid air, 

 but all attempts to collect the liquid hydrogen from the jet in vacuum 

 vessels failed. No other investigator has, so far, improved on the 



(T 



^fe 



Apparatus used in the production of the liquid hydrogen jet. 



results the author described in the Proceedings of the Chemical 

 Society (No. 158), 1895, or, indeed, touched the subject since that date. 

 The type of apparatus used in these experiments worked well, so it 

 was resolved to construct a much larger liquid-air plant, and to com- 

 bine with it circuits and arrangements for the liquefaction of hydrogen, 

 which will be described in a subsequent paper. This apparatus took a 

 year to build up, and many months have been occupied in testing and 

 making preliminary trials. The many failures and defeats need not be 

 detailed. 



On May 10 of this year, starting with hydrogen cooled to —205°, 

 and under a pressure of 180 atmospheres, escaping continuously from 



