Lerrs & BLake— The Carbonic Anhydride of the Atmosphere. 177 
both Whit Monday and the August Bank Holiday of last year 
the carbonic acid only amounted to 3:3 parts.’ ? 
During Reiset’s investigations of the air near Dieppe, he 
says :—‘‘ The presence of a flock of three hundred sheep in the 
neighbourhood of the apparatus during a fine calm day was 
revealed by a notable augmentation in the proportion of the 
carbonic anhydride: 3:178 volumes were obtained in 10,000.” 
(Average for Dieppe, 2:963.) 
Another very remarkable case of the effects of purely local 
conditions has been recorded by Lewy (in 1847).? 
“The analyses,” he says, ‘of the abnormal air of New 
Granada present us with results not less interesting. From time 
to time once or twice in the year the atmosphere of New Granada 
contains an extraordinary proportion of carbonic anhydride, which 
coincides with an appreciable decrease of oxygen, and consequently 
alters the composition of the atmosphere in a very marked manner. 
The great number of volcanos which exist in the New World, and 
the clearing of forests which is effected every year in this country, 
may cause the alteration. It is, in fact, during these clearances 
that the constitution of the atmosphere experiences the extra- 
ordinary changes I have mentioned. 
“These clearings, which are effected by vast conflagrations, 
called in the country /as quemas, produce considerable quantities of 
carbonic anhydride, which, mixing with the atmosphere, alter its 
composition. ‘The amount of carbonic anhydride which I found in 
this air rose in some analyses to 49 in 10,000, diminution in 
oxygen sometimes to 0°68 (per cent.). Instead of 21:01 I found 
only 20.33.” 
In the examples noticed above the conditions may be said to be 
artificial. The question however arises whether locality itself, 
apart from such conditions, has any distinct influence, and we 
think that the answer must be given in the affirmative. At least 
it would seem that there is a fair agreement in the results of a 
number of different investigators, that the air of inland localities 
is richer in carbonic anhydride than that of districts either situated 
at the seaside itself or near it, or even in the neighbourhood of 
1 Russell: Monthly Weather Reports Met. Council, April, 1884, p. 15s 
2Lewy, “Journ. prakt. Chem.,” 54[1851], p. 253, and Phil. Mag., [4] 2 [1851], 
p- 500. 
