History of Air-Analysis 



25 



the lower, though the reverse might be expected from the enormous consumption of 

 oxygen by daily processes on the surface of the earth, when we know of no proportionate 

 consumption of azote. It appears, however, that the disproportion of the two elements 

 at different elevations is by no means so great as theory requires; and therefore we must 

 conclude the unceasing agitation of the atmosphere by currents and counter-currents is 

 sufficient to maintain an almost uniform mixture at the different elevations to which 

 we have access. 



His experimental evidence consists of analyses of samples from Mount 

 Helvellyn (3000 feet), Snowdon (3570 feet), two balloon journeys made 

 by Green at 9600 feet and 15,000 feet respectively, and three samples 

 from Switzerland sent by Crewdson from Mer de Glace, the Simplon 

 Pass, and the Wengern Alps. The results, together with an abstract of 

 the many analyses of Manchester air made for comparison, are given in 

 table 4. 



Referring to the results obtained from these analyses, Dalton says: 



The general conclusions, it seems to me, to be drawn from these experiments are, that 

 the proportion of oxygen to azote in the atmosphere on the surface of the earth is not 

 precisely the same at all places and times; and that in elevated regions the proportion of 

 oxygen to azote is somewhat less than at the surface of the earth, but not nearly so much 

 so as the theory of mixed gases would require; and that the reason for this last must be 

 found in the incessant agitation in the atmosphere from winds and other causes. 



Numerous computations as to the composition of the atmosphere in 

 higher strata, based upon Dalton's hypotheses, have been made from time 

 to time by Babinet, 1 Benzenberg, 2 Bauer, 3 Morley, 4 and Hinrichs. 5 The 

 values computed by Morley and Hinrichs are given in table 3. 



Table 3. Percentages of oxygen in high-strata air, as computed by 



Morley and Hinrichs. 



1 Cited by Dumas and Boussingault, Annales de Chimie et Physique, 1841, 3d ser., 

 3, p. 258. 



2 Benzenberg, Poggendorff 's Annalen der Physik und Chemie, 1834, 3 1 , p. 8. 



3 Bauer, Poggendorff's Annalen der Physik und Chemie, 1868, 135, p. 135; also 

 Zeitschrift fur analytische Chemie, 1869, 8, p. 397. 



4 Morley, The American Journal of Science, 1879, 3d ser., 18, p. 168. 



5 Hinrichs, Comptes rendus, 1900, 131, p. 442. 



