History of Air-Analysis 



29 



THE FOUNDATIONS OF MODERN AIR-ANALYSIS. 



About 1840, Bunsen in Marburg, working with that marvelous tech- 

 nique that characterized all of his chemical observations, developed to the 

 highest degree the explosion method with hydrogen for determining oxy- 

 gen. A preliminary description of much of his technique was published 

 in an article by Kolbe. 1 Bunsen's apparatus is there described and to 

 demonstrate the accuracy of the apparatus several analyses of atmos- 

 pheric air were made in 1846. These analyses with slightly corrected 

 figures are given again in detail in Bunsen's book, 2 and are reproduced 

 in table 7. 



Bunsen expressed the belief that the composition of the air could be 

 determined much more accurately if the eudiometer readings were re- 

 peated from hour to hour. One such analysis made on May 31, 1847, 

 gave 20.964 per cent. 



Table 7. Results obtained by Bunsen with the hydrogen-explosion method. 



Date. 



Oxygen. 



1846 



Jan. 9 



Jan. 11 



Jan. 13 



Jan. 14 



Jan. 18 



Jan. 20 



p. ct. 



\ 20.970 



\ 20.963 



20.927 



20.914 



20.950 



With another 



eudiometer 



\ 20.906 



} 20.928 



\ 20.927 



) 20.927 



Date. 



Oxygen. 



p. ct. 



\ 20.919 

 1 20.880 



20.921 

 I 20.943 

 j 20.927 

 I 20.934 

 \ 20.928 

 } 20.911 



20.889 

 / 20.892 



Date. 



1846 



Feb. 1 



Feb. 



Feb. 

 Feb. 



5 



8 



Oxygen. 



p. ct. 

 20.840 

 20.859 

 20.925 

 20.940 

 20.937 

 20.952 

 20.953 



These figures of Bunsen marked a great advance in accuracy, and it is 

 important to note that Bunsen's method subsequently received exten- 

 sive use by different investigators. An extract from a letter written by 

 Bunsen to J. J. Berzelius on November 3, 1846, is of especial interest in 

 connection with the main problem of this memoir. 3 



Ich habe zunachst meine Aufmerksamkeit auf einige Fragen tiber die Zusammen- 

 setzung der atmospharischen Luft gerichtet und befinde mich im Besitz von mehr als 

 300 gleichzeitig in Marburg, Copenhagen, Reykjavik, in der Nahe des Polarkreises und 

 auf dem atlantischen Ocean aufgefanger, und in zugeschmolzenen Glasgefassen be- 

 wahrter Luft proben, die zu Analysen nach einer Methode ausreichen, deren Scharfe 

 und Sicherheit kaum etwas zu wunschen ubrig lasst, wie die nachstehenden zur Priifung 

 dieser methode in verflossenen Winter angestellten Versuche beweisen. 



1 Kolbe, "Eudiometer, Eudiometrie" in the Handworterbuch der Chemie, Liebig, 

 Poggendorff and Wohler, 1842, 2, p. 1050. 



2 Bunsen, Gasometrische Methoden, Braunschweig, 1857, p. 77. 



Gesammelte Abhandlungen von R. Bunsen, Leipzig, 1904, 2, p. 4. 



