M. Lewy on the Constitution of the Atmosphere. VTl 



tubing, with a little pair of bellows, which was moved suffi- 

 ciently long to be certain that the whole of the air contained 

 in the tube was replaced by the atmospheric air of the 

 locality, taking the necessary precautions to avoid any mix- 

 ture of the air of respiration ; as soon as the air was collected 

 the tubes were sealed before the lamp. 



I have divided the analyses into three series : 1st, Ana- 

 lysis of the atmospheric air of France ; 2d, Analysis of the 

 atmospheric air of the Atlantic Ocean and Carribean Sea ; 

 3d, Analysis of the air of New Granada. 



The comparison of the results obtained in this investiga- 

 tion with previous ones shows that the constitution of the 

 atmosphere is nearly the same in the New World and the 

 Old World. Taking the mean of the analyses, executed in 

 eleven different localities of New Granada, we find that 

 10,000 vols, of normal atmospheric air contain 4*008 car- 

 bonic acid, 2101-425 oxygen, and 7894*557 azote, which are 

 nearly the same proportions as those which have been found 

 for normal atmospheric air in various parts of Europe. 

 However, on examining carefully all the experiments hitherto 

 made on the constitution of the atmosphere, it is readily seen 

 that the composition of the air is not absolutely constant. 

 Perceptible differences exist, which vary with the meteoro- 

 logical conditions ; thus after a long rain the carbonic acid and 

 oxygen are always in smaller proportion than after a long 

 drought; however, these differences are only appreciable when 

 the analysis has been carried out with very great accuracy. 



In the New World, where the seasons are more defined 

 than in Europe, these variations are more easily detected. 

 During the fine season the normal air always contains a little 

 more oxygen and a little more carbonic acid than in the 

 season of the rains. Thus taking the mean of a large num- 

 ber of analyses, I found that 10,000 vols, of normal atmo- 

 spheric air of Bogota contain : 



During the rainy season. During the fine season. 

 Carbonic acid, 3822 4*573 



Oxygen, 2099*542 2102*195 



Azote, 7896-636 7893*232 



Volumes, 10,000000 Volumes, 10,000*000 



