NEW RESEARCHES ON LIQUID AIR. 139 



The same experiment 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 by allowing hydrogen to enter instead of air. 



Samples of air liquefied in sealed flasks. — In a paper " On the 

 relative behavior 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 Plate IV, illustrates how oxygen in A under 0.21 of an atmos- 

 phere pressure, and nitrogen in B under 0.79 of an atmosphere, 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 the capacity of more than 

 a liter. 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. The tubes must be drawn fine at 

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

 manner two oxygen flasks were compared. One was filled with gas 

 made from fused chlorate of potash contained in a side tube sealed onto 

 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 difference 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 0.04 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 Plate IV, 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, substan- 

 tially, the oxygen and nitrogen in air liquefy simultaneously, even 

 under gradually diminishing pressure, and that in these experiments 

 all the known constituents of air are condensed together. These 

 results finally disprove the view expressed in " A system of inorganic 

 chemistry," 1 by Professor Bamsay, 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 2 showed that the substance now known as argon 

 became solid before nitrogen, but chemical nitrogen and air nitrogen, 



1 1891, p. 70. 2 See Proc. Chem. Soc, Dec, 1894. 



