History of Air-Analysis 



59 



for Dresden, 20.90 per cent; and for Para, 20.89 per cent, respectively. 

 In the same month, therefore, the oxygen content in the neighborhood of 

 the poles was somewhat higher than in the neighborhood of the equator. 



In the oxygen values found in Bonn, only a single observation for each 

 day was given, or possibly these figures represent the average for each day. 

 They varied from 20.94 to 20.90 per cent. 



The values for the Cleveland samples, which also represent the oxygen 

 content alone, showed usually an exact agreement between duplicates on 

 the same day, and in only a few instances was there a discrepancy of 0.01 

 per cent. The averages ranged from 20.95 to 20.90 per cent. 



The total averages for these two places are: For Bonn, 20.922 per cent; 

 for Cleveland, 20.933 per cent. 



The total average value obtained by the analysis of 203 different air 

 samples, collected in five different places, and analyzed by three different 

 methods, is 20.91 per cent of oxygen. 



On an expedition to Cape Horn to observe the transit of Venus, 

 Muntz and Aubin 1 made analyses of air taken at Orange Bay, using the 

 eudiometer of Regnault and Reiset as modified by Schloesing. Their 

 results are given in table 43. The authors conclude that the average oxy- 

 gen percentage in the air taken near Cape Horn is less than the value 

 found by Regnault in Paris, but essentially that found in different parts 

 of the world; they believe, however, that the proportions of oxygen and 

 nitrogen are subject to variations which are within the narrow limits es- 

 tablished by Regnault. 



Table 43. Determinations of oxygen in atmospheric air, made by Muntz and Aubin. 



Phosphorus as an absorbent of oxygen again made its appearance in 

 air-analysis in the hands of Ebermayer, 2 who analyzed air from forests in 

 1885. He found in free atmospheric air 20.82 per cent of oxygen. 



Breslauer 3 analyzed air in Brandenburg at least once a moDth, some- 

 times as frequently as two or three times each month from January to 

 December. As an average of 20 analyses he gives 20.934 per cent, with 

 a minimum of 20.895 and a maximum of 20.955 per cent. 4 



1 Muntz and Aubin, Comptes rendus, 1886, 102, p. 421. 



2 Ebermayer, Fortschritte a. dem Gebiete der Agrikultur-Phys., 9, p. 229; abstracted 

 in Chemisches Centralblatt, 1886, 17, p. 770. 



3 Breslauer, Die chemische Beschaffenheit der Luft in Brandenburg a. H., Berlin, 

 1886. 



4 Breslauer, Deutschen Medizinal-Zeitung, 1885, 6, p. 1. 



