History of Air-Analysis 



45 



of 20.98 per cent. In dry and foggy weather, when the smoke of Man- 

 chester hung over the town, the results were as follows: 



Oxygen 

 percentage. 



Near center of town j 9088 



At laboratory j i^jj 



At laboratory, afternoon 20.91 



At laboratory, forenoon 21.01 



At laboratory, afternoon 20.82 



Average 20.91 



Table 26. Determinations made by Smith of oxygen in London air. 



Place. 



Islington, Duncan Terrace 



Hoxton, Hoxton Square 



Dalston, Albion Road 



Hackney, near Hackney Station . 

 Clarendon Square, Somers Town 

 Alpha Road and Grove Road . . 



Average 



Parks and open places. 



Near Belsize Park 



Kennington Park 



Chelsea Hospital, gardens near river . . . 



Vauxhall Bridge, near river 



Houses of Parliament, terrace 



Hyde Park, Sloane Street 20.91 



Middle of Hyde Park 21.03 



Average 



Average. 



p. ct. 

 20.835 

 20.835 

 20.905 

 20.835 

 20.895 

 20.835 



20.857 



21.010 

 20.940 

 20.910 

 20.905 

 20.945 

 20.925 

 21.005 



20.95 



In a very dense fog, which Smith states was a rare experience in Man- 

 chester, and which made the eyes smart and walking difficult, he found 

 20.82 and 20.89 per cent of oxygen. In the yard back of the laboratory 

 he regularly found somewhat less oxygen than in the front, his results 

 being 20.80, 21.01, 20.94, 20.84, 21.09 per cent, respectively, with an 

 average of 20.936 per cent. He summarized his results as follows : 



Oxygen 

 percentage. 



In very wet weather, in front of the laboratory 20.98 



At all times (average of 32 experiments) 20.947 



Behind the laboratory, in medium weather 20.936 



In foggy frost 20.91 



In outhouses 20.706 



If we except the air from outhouses, we find an average variation in 

 these analyses of 0.07 per cent. 



During 1863 to 1865 Smith made an extensive examination of the air 

 at both the summit and base of a number of mountains in Scotland. 

 While the altitudes were by no means as great as those of the Alps, and 

 hence the results, which are given in table 27, can not contribute exten- 



