Chemistry and Physics, 225 



lines and bands of terrestrial origin which it contains, especially 

 those dne to oxygen, are absent from sunlight before its entrance 

 into our atmosphere. Experiments showed that at this height the 

 bands of oxygen in the red, yellow and blue disappeared com- 

 pletely, the lines B and a became very much weakened and the 

 line A was scarcely visible. — C. P., cvii, 672, October, 1888. 



G. F. B. 



7. On the Compressibility of Oxygen, Nitrogen and Hydrogen. 

 — Amagat has subjected oxygen, nitrogen and hydrogen gases to 

 pressures up to 3000 atmospheres. He finds that at 1000 at- 

 mospheres the compressibility of gases is no greater than that of 

 liquids and increases similarly with the temperature. Calling the 

 density of water unity, the density of oxygen under a pressure of 

 3000 atmospheres is 1.1054, that of air is 0-8817 that of nitrogen 

 is 0-8293 and that of hydrogen is 0-0887.— C. P., cvii, 522, Sep- 

 tember, 1888. G. F. B. 



8. On the Meat of Vaporization of Volatile Liquids. — Since 

 very little is known of the heat of vaporization of liquids which 

 boil at temperatures below 0°, Chappuis has undertaken the 

 determination of this constant in the case of methyl chloride 

 boiling at — 23*75°, of sulphurous oxide boiling at —10-08°, of 

 carbon dioxide boiling at — 78 - 5°, and of cyanogen boiling at 

 — 28*4°. The apparatus consisted of a glass cylindrical reservoir 

 having at top a glass spiral or worm, united above to a larger 

 tube cemented into a steel cylinder the opening in which could 

 be closed by a screw cone. A lateral tube permitted this cylinder 

 to be put in communication with a steel reservoir. The whole 

 weighed about 100 grams. This apparatus is exhausted, the res- 

 ervoir is attached, and the cylinder is two-thirds filled with the 

 liquid to be examined. It is then placed in an ice-calorimeter of 

 Buusen and the cylinder and worm surrounded with mercury. 

 On opening the compression tap, the liquid evaporates slowly, the 

 heat of vaporization being taken from the calorimeter. After the 

 experiment is ended the apparatus is again weighed. Knowing 

 the mass of the liquid evaporated, the volume of mercury issuing 

 from the calorimeter and the constants of this instrument, the 

 heat of vaporization may be calculated. The results obtained 

 were as follows : For methyl chloride at 0°, the heat of vaporiz- 

 ation is 96'9 calories; for sulphurous oxide 91-7 calories; for 

 carbon dioxide 56-25 calories ; and for cyanogen 103-0 calories. If 

 these values are referred to the gaseous volume corresponding to 

 the molecular mass in grams, i. e., 22-32 liters, we obtain 4-86, 

 5-90, 2-48 and 5-36. — Ann. Chim. Phys., VI, xv, 498, December, 

 1888. G. F. B. 



9. On the Combination of Oxygen and Nitrogen in Gaseous 

 Explosions. — It is well known that when hydrogen, in presence of 

 nitrogen, is exploded with excess of oxygen, the nitrogen is itself 

 to a certain extent oxidized. If the eudiometer contains a seven 

 per cent solution of sodium hydrate, the nitrogen oxide produced 

 is absorbed and the liquid contains nitrite and nitrate. Veith 



