458 SCIENTIFIC RECORD FOR 1884. 



entirely unnecessary to use liquid oxygen. Studying nitrogen as above, 

 he obtained the following values of pressure and temperature : At 35 at- 

 mospheres (the critical pressure) the temperature was — 140o (the critical 

 temperature) ; at 31 atmospheres — 148.2° ; at 17 atmospheres —100.5° ; 

 at 1 atmos])here, —194.4; and in vacuo, —213°. This, then, was the tem- 

 perature actually attained in the experiments with hydrogen above de- 

 cribed. The author differs from Wroblewski, since with oxygen boiling 

 under a pressure of only one atmosphere, and even under an expansion of 

 100 atmospheres, he obtained no trace of liquefaction with hydrogen. In- 

 deed, it was only with oxygen boiling in a vacuum, and hence giving a 

 lower temperature by 17°, and under expansion of the gas compressed to 

 190 atmospheres, that the first trace of liquefaction appeared. The liquid 

 hydrogen enabled Dumas to say that it certainly was not a metal, as 

 many had been led to believe it would be. It was a colorless, transpar- 

 ent liquid. Continuing his researches, Olszewski next used air as the 

 refrigerant, having obtained 6 c.c. of it. The air was compressed in bat- 

 terer's apparatus and allowed to pass into a glass tube cooled to —142° 

 to —150° by means of ethylene. Xo meniscus was observed at 50 at- 

 mospheres, although this is superior to the critical pressure. On dimin- 

 ishing the pressure to 37.C atmospheres, the air began to boil and the 

 meniscus appeared at once. This pressure is below the critical press- 

 ure, the meniscus disappearing at 39 atmospheres. The following are 

 the observed values of pressure and temperature for air: At the press- 

 ire of 39 atmospheres the temperature was —140° (the critical point); 

 at 33 atmospheres, —142°; at 27.5 atmospheres, —146°; at 20 atmos- 

 pheres, — 152°; at 14 atmospheres, —158.5°; at 12.5 atmospheres, 

 —160.5°; at 6.8 atmospheres, —169°; at 4 atmospheres, —176; at 1 at- 

 mosphere, — 191.4° ; and in vacuo, —205°. Since the temperature under 

 which air boils in vacuo, calculated from that of oxygen, —198°, and ni- 

 trogen, — 213°, difl'ers considerably from —205°, it would seem that when 

 air is liquefied the relative proportion of its constituents is not pre- 

 served. {G. R., April, 1884, xcviii, 913 ; July, 1884, xcix, 133, 184.) 



Olszewski has liquefied carbon monoxide also, and has studied its prop- 

 erties. The gas was carefully purified from carbon dioxide, and com- 

 pressed to 70 atmospheres in l^atterer's pump, from whence it passed 

 to the apparatus used in liquefying oxygen and nitrogen. The follow- 

 ing values were observed : Under the pressure of 35.5 atmospheres the 

 temperature was — 139.5° (the critical temperature); at 25.7 atmospheres, 

 — 145.3° ; at 23.4 atmospheres, —147.7° ; at 21.5 atmospheres, —148.8°; 

 at20.4atmospheres,— 150.0°; at 18.1 atmospheres, -152°; at 16.1 at- 

 mospheres, -154.4° ; at 14.8 atmospheres, —155.7° ; at 6.3 atmospheres, 

 —168.2° ; at 4.6 atmospheres, -172.6° ; at 1 atmosphere, -190° ; and in 

 vacuo, -211°, the solidifying point. At temperatures between —139.5° 

 and —190° liquid carbon monoxide is colorless and transparent. In 

 vacuo the temperature falls to —211°, and it solidifies either in a snowy 

 mass, if the vacuum is rapidly made, or a compact, opaque mass, if the 



