65 
The main conclusions to be drawn from this paper may be 
briefly stated as follows : — 
1. That the sea does not act in increasing the amount of 
atmospheric carbonic acid. 
2. But that, on the contrary, the air over the sea contains 
a much smaller proportion of carbonic acid than the 
air of the land, although the influence of the sea in 
abstracting this gas from the atmosphere is not so 
great as the observations of Vogel and Kruger would 
indicate. 
3. That the mean quantity of carbonic acid contained in 
the normal atmosphere of the ocean is 3'00 in 10,000 
volumes of air. 
4 . That the proportion is constant, or nearly so, in different 
latitudes. 
5. That this proportion is not sensibly influenced by the 
different seasons of the year. 
6. That this proportion does not experience any percep- 
tible diurnal variation. 
II. “ On the Amount of Carbonic Acid contained in the 
Atmosphere of Tropical Brazils during the rainy season,” by 
T. E. Thorpe. 
The determinations contained in this communication of 
the amount of carbonic acid in the land air of the tropics 
were made at Para, the principal port of entrance of the river 
Amazon, situate about eighty miles from the sea, on the 
river Gram-Para, in lat. 1° 27' S., and long. 48° 28' W. This 
town is built on the verge of a vast primeval forest, extend- 
ing to the sea coast, and over which the trade winds of the 
Atlantic regularly blow during the greater part of the year. 
The determinations were made by Pettenkofers method, in 
the manner previously described. Hydrochloric acid was, 
however, substituted for oxalic acid in the titration of the 
baryta- water, since solutions of the latter acid decompose 
