COMPOSITION OF THE ATMOSPHERE. 



25 



higher hills are not the most deficient — it may be, because 

 in Scotland really high mountains do not exist, and also 

 because, unlike the great ranges of the Alps and the Hima- 

 layas, the Scotch hills have much sea and little land from 

 which to draw their supplies. 



It may be remarked that the averages of the hills above 

 and below, viz. ao'gS and 20*94, give exactly the number, 

 20'96, which was taken as a fair sample of air. 



Marshy or confined Places, Switzerland, &c. 



Oxygen. 



Means. 



Aug. 1864. Sion,UpperValleyoftheEhone,Switzer- "j 

 land (morning), over water, marshy I 

 grass J 



( 



Sion (morning) over water and brush- 

 wood 



Sept. 1864. 



Aug. 1864. 



Mean 



Eeddish, near Manchester, among I 

 brushwood j 



Mean 



Lauterbrunnen 



Mean 



Chamounix, Montanvert 



Mean 



Verdin, in the Sologne. . . 



Vouzerou 



Mean 



20-86 



2I"01 



2o'94 



2I"05 

 2 1 '02 



20*96 

 2o*94 

 20-95 

 2o'83 



21"00 



20-90 



20*92 

 20-98 



20-95 



20-90 



20-94 



20-97 



20-95 



21-03 

 20-99 



20'97 

 20-90 

 21-01 

 20-90 



20-95 



20-937 



20'953 



■95 



As there is so much cretinism at Sion, and as goitre is 

 found in the whole valley, I thought it important to obtain 

 some specimens of the atmosphere from the marshes them- 

 selves. The air was taken from the surface of the water 



