History of Air-Analysis 33 



During August 1841, on a journey from Paris to Copenhagen, he 

 collected samples on the North Sea, the results being 20.46, 20.42, 20.45, 

 and 20.43 per cent, with an average of 20.44 per cent. His low values 

 may possibly be ascribed to an error in weighing the glass balloon used. 

 Analyses were also made of air taken at Elsinore on the coast. Three 

 samples taken on February 18, 1842, gave 20.84, 20.83, and 20.84 per 

 cent respectively. The average was 20.837 per cent. On the return 

 journey from Copenhagen to France, 5 samples of air taken on the sea 

 were collected, the percentages of oxygen being 20.88, 20.91, 20.89, 21.01, 

 and 20.84, with an average of 20.907. 



Lewy also reports analyses of samples taken at Guadeloupe and ana- 

 lyzed in Paris. The results show abnormally high carbon-dioxide values 

 and low oxygen contents. When computed on the basis of carbon- 

 dioxide-free air, the oxygen content in 9 samples varies from 20.51 to 

 20.93 per cent. The author is inclined to attribute the exceptionally 

 high carbon-dioxide content to the nearby volcanoes. 



In Geneva, Marignac 1 found on three different days, in January and 

 February 1842, 20.81, 20.80, and 20.77 per cent of oxygen, with an average 

 of 20.799 per cent. Meanwhile, Stas 2 in Brussels found in 12 different 

 experiments during 1842 a minimum of 20.84 per cent and a maximum 

 of 20.87 per cent, but the author points out two analyses with no error 

 that could be accounted for in which the results showed 20.90 and 20.93 

 per cent. In general, however, Marignac, Lewy, and Stas, all using the 

 method of Dumas and Boussingault, obtained results that agreed with 

 those obtained by the latter investigators. 



In studying respiration, Marchand 3 reported air-analyses made in 

 Halle at 10 different times. The method was similar to that of Du- 

 mas and Boussingault. The percentages of oxygen obtained were as 

 follows: 



per cent. 



1 20.99 



2 20.97 



3 20.98 



4 20.90 



5 20.96 



per cent. 



6 20.89 



7 20.98 



8 20.99 



9 21.02 



10 21.03 



The average of these values, 20.97 per cent, was employed by him as 

 indicating the composition of normal air. 



Two years later, Marchand 4 published two analyses of outdoor air 

 in Halle which were made by the hydrogen-explosion method with results 

 as follows: 8 a.m., 20.920 per cent; 8 p.m., 20.912 per cent. 



In the attempt to establish some relationship between the com- 

 position of the air and the invasion of cholera, at least two investi- 

 gations on the oxygen content of the atmospheric air during a cholera 



1 Marignac, reported by Dumas in Comptes rendus, 1842, 14, p. 380. 



2 Stas, Comptes rendus, 1842, 14, p. 570. 



s Marchand, Journal fur praktische Chemie, 1848, 44, p. 1. 

 4 Marchand, Journal fur praktische Chemie, 1850, 49, p. 449. 



