CHEMISTRY. 5 1 3 



values usually given (4 to G volumes in 10,000) much too high. He gives 

 2,9G2 vols, in 10,000 as the mean of 220 experiments made near Dieppe. 

 The ratios obtained in Paris are somewhat higher, being 3,1G8 vols, of 

 carbonic anhydride in 10,000 of air. {A7in. Chim. et Phys. (5) xxvi, pp. 245 

 et seq.) 



A. Mnntz and E. Aubin have also made determinations of the pro- 

 portions of carbonic anhydride in the atmosphere- at Paris and near 

 Vinceuues, and the results (which confirm Reiset's figures) show that 

 the variations in the amount of carbonic anhydride are due to local in- 

 fluences, and that in general the heavier gas is quite uniformly distrib- 

 uted throughout the lower strata of tbe atmosphere. These chemists 

 also examined the air of elevated regions, conducting experiments at 

 the altitude of 2,S77 meters (9,422 feet) in the Pyrenees. Although the 

 direction of the wind and state of the atmosi)here varied greatly during 

 their experiments, the proportion of carbonic anhydride was found to 

 be constant, being about 2.86 vols, in 10,000 of air. For the sake of 

 comparison the air was examined in two valleys at the foot of tbe 

 Pyrenees, one near Pierrefitte (507 meters above the sea-level) and the 

 other near Luz (730 meters) ; at the first station the air was found to 

 contain 2.79 vols, of carbonic anhydride in 10,000, and at the second 

 2.G9 in 10,000, the latter determination being made in the midst of lux- 

 urious V( getation. Muntz and Aubin conclude that carbonic anhydride 

 is very uniformly distributed throughout the atmosphere, and regard 

 their results as confirming Eeiset's statements and Schloesing's theories 

 concerning the circulation of carbonic anhydride upon the surface of 

 the earth. {Comptes Keiidus, xoiii, p. 797.) 



Dr. Edward W. Morley has devised a method for accurate and rapid 

 analyses of air, and has made a series of daily analyses in duplicate of 

 air collected at Hudson, Ohio, for six months, beginning with January 

 1, 1880, and one for six months and twenty days, beginning October 1, 

 1880. For details of the apparatus and process we refer to the original 

 paper. Each pair of analyses occupied about 70 minutes of time, and 

 the mean error of a single analysis for half a month was less than the 

 thousandth part of one per cent. By comparing the results of this long 

 series of daily determinations with the data obtained from the thrice- 

 daily maps of the state of the weather furnished by the United States 

 Signal Service Bureau, Dr. Morley finds that most of the variations in 

 the amount of oxygen are caused by the vertical descent of air from 

 high elevations. This descent of cold air seems to be the effect of 

 sudden and severe depressions of temperature rather than the cause ; 

 the descent follows the cold by a day or two, and the decrease in amount 

 of oxygen begins simultaneously with the descent from above. {Proo. 

 Am. Assoc. Adv. ScL, 1881 ; abstract in Chem. iVe?rs, XL, pp. 245, 284 et 

 scq ) 



II. Mis. 2G So 



