54 Composition of the Atmosphere 



von Jolly, Kreusler made a series of analyses of atmospheric air in Bonn. 

 These observations covered the whole year, averaging about 8 or 9 ex- 

 periments each month, March excepted. About the middle of the year, 

 certain improvements were made in the apparatus. His results are ab- 

 stracted in table 37. 



As a result of his experiments, Kreusler found that the oxygen varied 

 from 20.867 to 20.991 per cent as the extreme limits, but with certain ex- 

 ceptional cases eliminated, the variations were from 20.88 to 20.94 per 

 cent. The 99 observations in the year 1883 gave an average result of 

 20.911 per cent. The average values for each month were as follows: 



January 20.910 



February 20.911 



March 



April 20.910 



May 20.910 



June 20.917 



July 20.918 



September 20.913 



October 20.909 



November 20.905 



August 20.920 December 20.906 



The slightly higher values found during the warmer months are ex- 

 plained by Kreusler as being due to the assimilative activity of vegetation. 



In referring to earlier analyses, Kreusler considers all experiments in 

 which the variations were under 0.1 per cent as normal results, those be- 

 tween 0.1 and 0.15 abnormal, and those over 0.15 per cent as most ab- 

 normal. Of the 1025 observations that he has been able to find in the 

 literature which are comparable, but 15 can be classified under the head 

 of "abnormal" and 22 under the head of "most abnormal." The ob- 

 servations of von Jolly in Munich in 1878 play an important role in this 

 subdivision, for his results give 12 normal, 3 abnormal, and 6 most abnor- 

 mal; Kreusler points out that while in the case of the other observations 

 97.2 per cent are normal and only 1.2 and 1.6 are abnormal and most ab- 

 normal, respectively, the experiments of von Jolly give but 57 per cent 

 normal, with 14.3 and 28.6 per cent, respectively, as abnormal and most 

 abnormal. Obviously, therefore, von Jolly has found much greater vari- 

 ations than all the other observers combined, and consequently Kreus- 

 ler takes exceptions to his conclusions. Furthermore, the average oxy- 

 gen content found in von Jolly's experiments was 20.75 per cent, which is 

 very much lower than both the earlier and later observations. 



After considering the errors in von Jolly's experiments, Kreusler dis- 

 cusses the anomalous observations of Brunner, Lewy, Regnault and Lewy , 

 Liebig, Macagno, and Morley, and says in conclusion : 



Ich glaube hiermit den Nachweis geliefert zu haben, class die ja lange Zeit herrschend 

 gewesene, neuerdings aber mehrfach wieder in Zweifel gezogene Annahme einer inner- 

 halbenger Grenzen konstanten Zusammensetzung der atmospharischen Luft that- 

 sachlich noch zu Recht besteht, insofern alle entgegengesetzten Beobachtungen bis 

 jetzt nicht geniigend verbiirgt scheinen. 



In testing his extremely complicated apparatus for gas-analysis, 

 Geppert 1 made a number of air-analyses, employing the hydrogen ex- 



1 Geppert, Die Gasanalyse und ihre physiologische Anwendung nach verbesserten 

 Methoden, Berlin, 1885, p. 96. 



