292 CHEMISTRY. 



Loomis's theory that sudden depressions of temperature are caused by 

 the vertical descent of cold air from the higher portions of the atmos- 

 phere, the author conceived that such air might well contain a smaller 

 l^roportion of oxygen than the average. In preparation for testing the 

 question, he has made a number of experiments with apparatus specially 

 constructed. In proof of its accuracy, he states that the probable error 

 of a determination of oxygen in the air, is the 7200th part ; and the prob- 

 able difference of two determinations on the same sample is the 5200th 

 part. The air analyzed was taken in the open country during Decem- 

 ber, 1878, and January and February, March and April, 1879. The mini- 

 mum of oxygen observed was found in a sample taken on the 26th of 

 February, when it was 20.45 and 20.50 in two experiments. The maxi- 

 mum occurred in air taken on the 28th of December, 20.98 and 20.96 in 

 two analyses. — {Am. J. Sci., Ill, xviii, 168, September, 1879.) 



Boussingault has investigated the production of oxygen from barium 

 dioxide under diminished pressure, and shows that in a vacuum this sub- 

 stance parts with oxygen at a low red heat. Conversely at about the 

 same temperature, but at ordinary i^ressures, oxygen is readily absorbed 

 again from the atmosphere by the lower oxide. Barium oxide may be 

 successfully employed, therefore, on the large scale for obtaining i^ure 

 oxygen from the atmosphere. The difficulty hitherto experienced was 

 the fact that at the high temperature necessary to decompose the dioxide 

 under ordinary pressures, some molecular change took i)lace which 

 diminished largely its power of absori^tion. — {Ann. Chini. Phys., V, xix, 

 461, April, 1880.) 



Hautefeuille and Chappuis have announced to the French Academy 

 the liquefaction of ozone. By the use of a very low temperature they 

 have succeeded in producing from oxygen, by the silent electric discharge, 

 a greater quantity of ozone than hitherto, this at — 23<^ C. being 21 i^er 

 cent. The ozonized oxygen was conducted into the cool tube of a Cail- 

 letet's apparatus and pressure applied. After a few strokes of the pumj) 

 the gas appeared azui'e blue in color, which increased with the pressure 

 to dark indigo blue. On suddenly expanding the gas under 95 atmos- 

 pheres pressure, a mist api)eared in the tube, indicating liquefaction. — 

 {yature, xxii, 560, October, 1880.) 



Ogier has succeeded in effecting the combination of hydrogen chlo- 

 ride and hydrogen phosi)hide gases by comj^ressing them together in a 

 Cailletet's apf>aratus. When equal volumes of these two gases were com- 

 pressed by a pressure of 14 atmospheres at 14°, combination took p'ace 

 and small yellow crystals, very brilliant, appeared in the tube. If the 

 l>rox>ortion had been accurately made and the gases were i)ure, they 

 disappeared entirely, the walls of the tube being covered with the crystals 

 with no trace of liquid. If, however, the upfter part of the tube be warmed 

 with hot water to 20^, a liquid layer ajipears. If now the tube be cooled 

 slowly, maintaining the i^ressure at 60 to 70 atmospheres, a point is 

 reached when combination takes place and crystals are formed. A 



