CHEMISTRY. 513 



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

 2,962 vols, ill 10,000 as tbe mean of 220 experiments made near Dieppe. 

 The ratios obtained in Paris are somewhat higher, being 3,108 vols, of 

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

 et seq.) 



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

 portions of carbonic anhydride in the atmosphere at Paris and near 

 Yincennes, 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 the atmosphere. These chemists 

 also examined the air of elevated regions, conducting experiments at 

 the altitude of 2,577 meters (9,422 feet) in the Pyrenees. Although the 

 direction of the wind and state of the atmosphere 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 the 

 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 

 2.69 in 10,000, the latter determination being made in the midst of lux- 

 urious vegetation. Muntz and Aubin conclude that carbonic anhydride 

 is very uniformly distributed throughout the atmosphere, and regard 

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

 concerning the circulation of carbonic anhydride upon the surface of 

 the earth. {Comptes Reiuhis, xciii, 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 obtaiued 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. Sci., 1881 ; abstract in Cheni. Ifeics, XL, pp. 245, 284 et 

 seq.) 



II. Mis. 20 33 



