650 SCIENTIFIC RECORD FOR 1885. 



his apparatus a second tube of very thin glass, and thus isolates the 

 liquefied gases by a double gaseous stratum. The pressure and the 

 temperature being greatly lowered he has been able to solidify nitro- 

 gen, carbon monoxide, formene, and nitrogen dioxide, and to determine 

 at the same time the temperatures of solidification. Nitrogen solidifies 

 at — 2140 under a pressure of 60 atmospheres ; carbon monoxide at — 

 2070 under 100°^™ pressure; formene at — 1850-8 under 80™™ pressure; 

 and nitrogen dioxide at — 167° under 138™™ pressure. The latter forms 

 a colorless liquid. By reducing the pressure of solid nitrogen down to 

 4mm Qf mercury he has succeeded in obtaining the lowest temperature 

 known, —225° C. (—373° F.). Comptes rendus,G: 350 and 940. 



Separation of Liquefied Air into Two Distinct Liquids (by S. Wrob- 

 lewski). — The laws of the liquefaction of air are not those of the liquefac- 

 tion of a simple gas. If at first sight air presents itself in such a man- 

 ner that it is permissible to speak of the critical point of air, this de- 

 pends merelj' on the slight difference which exists between the curves 

 of tension of watery vapor, of oxygen and of nitrogen. The author 

 obtained air as two distinct liquids sei)arated by a perfectly visible me- 

 niscus, as follows: After having liquefied at —142° a quantity of air in 

 the tube of his apparatus, he allows such a quantity of gaseous air to 

 enter the tube that the pressure of the gas is equal to 40 atmospheres and 

 its optical density equal to that of the liquid. The meniscus of the liquid 

 disappears entirely. He then slowly diminishes the pressure, and at 

 the moment when the gauge shows a pressure of 37-6 atmospheres a new 

 meniscus appears at a point of the tube much higher than that occupied 

 by the meniscus that has disappeared. A few moments afterward the 

 old meniscus returns to the point where it disappeared, and at this mo- 

 ment two liquids are distinctly recognized and remain separate for some 

 seconds. The lower liquid contains 21.28 vols, per cent, of oxygen, and 

 the upper 17*3 to 18-7 per cent. {Comptes rendus, ci, No. 13.) 



Solutions of Ozone and the Chemical Action of Liquid Oxygen. — At the 

 Aberdeen meeting of the British Association for the Advancement of 

 Science, Professor Dewar gave a description of the apparatus and 

 method employed by him in the liquefaction of such gases as oxygen, 

 &c., and after discussing the conditions required for the successful con- 

 version into the liquid of the gases formerly called i^ermanent, he gave 

 an account of some experiments with liquid oxygen. At —130° liquid 

 oxygen loses the active characters possessed by this element in the 

 gaseous state; it is without action on phosphorus, sodium, potassium, 

 solid sulphuretted hydrogen, and solid hydriodic acid. At very low 

 temperatures other substances are similarly without action on each 

 other; thus liquid ethylene and solid bromine may be brought in contact 

 without any action taking j)lace, whereas gaseous ethylene and liquid 

 bromine unite directly at the ordinary temperatures. 



