153 French National Instihtte. 



from the atmosphere ; and every thing is so new on the sub- 

 ject, that it ought not to excite our astonishment that various 

 explanations are still sought after. 



We alluded last year to the remark of M. Vauqiielin, that 

 several metallic substances, very similar to atmospheric 

 stones, are evaporated from lofty furnaces. 



M. Seguin has endeavoured to collect all the analogous 

 facts known in chemistry or medicine, such as the delete- 

 rious vapour.s of lead, mercury, the phsenomena of salts 

 diifused in air. vapour, rain-water, &c. ; all the metallic or 

 other substances which hydrogen gas can dissolve ; the 

 quantity of odours, and of miasmata, not recognisable 

 by our eudiometers. From all these M. Seguin easily 

 proves that the composition of the atmosphere is very hi tie 

 known to us, and that several of its vapours being very light 

 may be accumulated in the upper regions ; but the difficulty 

 of uniting a sufficient quantity before their falling down, iii 

 order to form aerolites of the size generally observed, re- 

 mains unsolved. 



M. Theodore de Saussurc has presented a very interesting 

 analysis of alcohol and sulphuric ether. He operated by 

 combustion, both with alcohol by itself and in the state 

 of vapour: by means of decomposition by simple heat, he 

 determmed the quantity of water and of carbonic acid pro- 

 duced, as well as the respective quantities of their elements 

 in oxygen, carbon, and water; finally, he has drawn a mean 

 result from all his operations, and concluded the composii 

 tion of alcohol to be as follows : 



Carbon - - 0-4565 

 \ Oxygen - - 0"3733 



Hydrogen - - 0-1494 

 Azote - - 0-0333 



Cinder (Cendre) 0-0004 



1-0000 



And that of ether: 

 Carbon - - 0'583 

 Hydrogen - - 0-2214 

 Oxygen - - 0*1966 



1-0000 



Finally, he shows that these two analyses agree with the 

 quantity of ether furnished by a given quantity of alcohol, 

 and bv the analysis of what remains after ctherification. 



This 



