422 



Sir W. Bamsay. Estimate of the Relative [Mar. 9 7 



During these runs the pressure was kept at 190 atmospheres; and 

 the delivery of air through the escape valve of the liquefier remained 

 fairly uniform. Separate readings, taken at different times, of the- 

 amount of air passing the meter gave 0-244, 0*230, 0*258, 0*261, 0*248,, 

 and 0*239 kilos, per minute; these figures testify to fairly uniform 

 working. 



It was of interest to see whether argon concentrated itself in the- 

 liquefied portion of the air, or whether most of it escaped as gas. 

 The boiling points of the principal atmospheric gases are, on the- 

 absolute scale: — nitrogen, 77°*54; argon, 86°*90; oxygen, 90°*5 ; the 

 differences are 9°*36 and 3°*6 respectively ; it was therefore to be 

 expected that the argon would concentrate in the liquid. 



An experiment was therefore made in which 12*73 grammes of 

 freshly collected liquid air was allowed to boil in a double-walled 

 vacuum-tube, and the gases were led directly over metallic copper and 

 magnesium lime; the resulting argon measured 165 c.c. at 0° and 

 760 mm. pressure. The weight of this argon was 0*2943 gramme, or 

 from 1 gramme of liquid air, 0*02312 gramme. Now 1 gramme of 

 atmospheric air contains 0*0129 gramme of argon; hence the process 

 of liquefaction nearly doubles the content of argon in the air. It is, 

 therefore, very advantageous to prepare argon from air which has 

 been liquefied. 



Acting on this suggestion, it appeared a fortiori probable that if the 

 percentage of argon in air were doubled by liquefaction, the krypton 

 and the xenon would be practically wholly removed and liquefied. 

 And by submitting liquefied air to a second liquefaction, by boiling- 

 it off through the compressor, it appeared to hold that a concentration 

 of the krypton and xenon would result, and that they would be found 

 wholly in the liquefied portion. An experiment was therefore begun 

 in which about 100 kilos, of gaseous air were passed through the 

 liquefier ; the liquefied portion, amounting to about 6 kilos., was again 

 passed through the liquefier, somewhat added to by gaseous air, drawn 

 in by the compressor. By an unfortunate accident, however, nine- 

 tenths of the air collected during the second liquefaction was lost 

 and the amount of xenon and krypton in the remaining tenth, repre- 

 senting about 10 kilos, of gaseous air, did not appear to justify repetition 

 of the troublesome experiment. I have no doubt, however, that had 

 these experiments not had for their object the determination of 

 quantity, but only the preparation of krypton and xenon, they would 

 have effected the separation well. 



The liquid air, resulting from the liquefaction of 6 per cent, of 

 191*1 kilos, of gaseous air, was sucked, several litres at a time, into a 

 large glass balloon of about 5 litres capacity, fitted with an india- 

 rubber cork, through which a wide tube passed, connected with a 

 double-acting Fleuss pump, driven by an electric motor. Through 



