I'roi's. S. I). I.iv<-in_ f and .1. I>ewar. 



rondcii-cd. communication with the outer air \\.i- < lo--d >ty a stop- 

 i -ock. Sulequently, communication was ojKMied, Through another 

 stop-cork, with a second vessel coole<l by immersion in liquid hydrogen, 

 and a part of the liquid from the first vessel, maintained at - -'10', 

 was allowed to distil into thr -croud still colder \ es>cl. When about 

 10 c.c. had condensed in the solid form in the -fund \e--cl. communi- 

 cation with the first vessel was cut off, and a manometer showed a 



;re of gas of about 10 to 15 mm. of mercury. 



This mixture of gases was passed into tubes previously exhausted by 

 a mercury pump, but before reaching the tubes it had to pass through 

 a U-tul>e immersed in liquid hydrogen so as to condense less volatile 

 gases, such as argon, nitrogen, oxygen, or carbonic oxide, which might 

 be carried along by those more volatile. Previous trials with tubes filled 

 in the same way, except that the U-tule in liquid hydrogen was omitted, 

 showed that these tubes contained traces of nitrogen, argon, ami com- 

 pounds of carbon. The tubes filled with gas which had ]>assed through 

 the T-tube showed on sparking no spectrum of any of these la-t- 

 mentioned gases, but showed the spectra of hydrogen, helium, and 

 neon brilliantly, as well as a great many less brilliant rays of unknown 

 origin. In addition, they showed at first the brightest rays of mercury, 

 derived, no doubt, from the mercury pump by which they had been 

 exhausted before the admission of the gases from the liquefied air. 

 After some sparking the mercury rays disappeared, probably in . onse- 

 quence of absorption of the mercury by the electrodes, which were of 

 aluminium. 



In one experiment the mixture of gases in the second vessel, into 

 which a fraction of the liquefied air was distilled as above described, 

 was pumped out without being pa.-sed through the I'-tube in liquid 

 hydrogen and examined. This mixture was found to contain 43 JKT 

 cent, of hydrogen, 6 per cent, of oxygen, and 51 per cent, of other 

 -<$ nitrogen, argon, neon, helium, &c. and it was explosive when 

 mixed with more oxygen. This shows conclusively that hydrogen 

 in sensible proportion exists in the earth's atmosphere, and if the earth 

 cannot retain hydrogen or originate it, then there must l>e a continued 

 accession of hydrogen to the atmosphere (from interplanetary space), 

 and we can hardly resist the conclusion that a similar transfer of 

 other gases also must take place. The tul>es containing the residue of 

 atmospheric gases uncondensed at the temperature of liquid hydrogen 

 we have examined spectroscopically. 



On passing electric discharges through them, without any condenser 

 in the circuit, they glow with a bright orange light, not only in the 

 capillary part, but also at the poles, and at the negative pole in 

 particular. The spectroscope shows that this light consists in the 

 visible part of the spectrum chiefly of a succession of strong rays in 

 the red, orange, and yellow, attributed to hydrogen, helium, and neon. 



