1896.] on New Researches on Liquid Air. 137 



thermometer, or — 216° C. On allowing the air to enter, the solid 

 instantly melts and more liquid air is formed. The same experi- 

 ment may be repeated many times by simply opening and shutting 

 the stopcocks. When the liquid air loses too much nitrogen, then it 

 no longer solidifies. This apparatus may be used to show that when 

 liquid air is running freely into B, liquefaction is instantly arrested 

 l)y allowing hydrogen to enter instead of air. 



Samples of Air Liquefied in Sealed FlasJcs. — In a paper " On the 

 relative behaviour of chemically prepared and of atmospheric nitro- 

 gen," communicated to the Chemical Society in December 1894, the 

 plan of manipulating such samples was described. The arrangement 

 shown in Fig. 4 illustrates how oxygen in A under 0*21 of an atmos. 

 pressure, and nitrogen in B under • 79 of an atmos., can be compared 

 as to the first appearance of liquefaction in each, and finally as to their 

 respective tensions when the temperature is as low as that of solid 

 nitrogen. The flasks A and B have a capacity of more than a litre. 

 Each has a manometer sealed on, and in each phosphoric anhydride 

 is inserted to secure dryness. A large vacuum vessel C holds the 

 liquid air, which is gradually lowered in temperature by boiling 

 under exhaustion. The moment liquefaction takes place, the tubes 

 D', D" begin to show liquid. These tubes must be drawn fine at the 

 end when accurate observations are being made. In the same manner 

 two oxygen flasks were compared. One filled with gas made from 

 fused chlorate of potash, contained in a side tube sealed on to the 

 flask. The other was treated in the same way, only the chlorate had 

 a little peroxide of manganese added. The former gave perfectly 

 clear blue liquid oxygen, the latter was turbid from solid chlorine. 

 Two flasks of dry air that had stood over phosphoric anhydride were 

 liquefied side by side, the only difierence between the samples being 

 that one was free from carbonic acid. The one gave a liquid that 

 was perfectly clear, the other was turbid from the • 04 per cent, of 

 carbon dioxide. 



The temperature was lowered by exhaustion until samples of 

 liquid air from two flasks placed side by side as in Fig. 4 became 

 solid. The flasks were then sealed off" for the purpose of examining 

 the composition of the air that had not been condensed. The one 

 sample contained oxygen, 21*19 per cent., and the other 20*7 per 

 cent. This is an additional proof to the one previously given that, 

 substantially, the oxygen and nitrogen in air liquefy simultaneously, 

 even under gradually diminishing pressure, and that in these ex- 

 periments all the known constituents of air are condensed together. 

 These results finally disprove the view expressed in ' A System of 

 Inorganic Chemistry,' * by Professor Ramsay, where he says : " Air 

 has been liquefied by cooling to —192°, but as oxygen and nitrogen 

 have not the same boiling points, the less volatile oxygen doubtless 

 liquefies first." My old experiments! showed that the substance 

 now known as argon became solid before nitrogen, but chemical 



* 1891, p. 70. t See Proc. Chem. Soc. Dec. 1894. 



