Chemical Science, 393 



evaporation, found to contain sebacic acid, and an extractive matter 

 becoming brown by contact with air. 



The portion insoluble in water was washed in hot water, and 

 treated with magnesia, which combined with it; boiling water 

 then separated an efflorescent white salt, containing an acid re- 

 sembling the volatile one described above. The insoluble salts, 

 treated with alcohol, yielded to it a portion of fluid fatty matter, not 

 acid. Ether completed the separation of this substance. 



The residue decomposed by muriatic acid, gave a substance com- 

 posed entirely of margaric and oleic acids. — Annates de Chimie, 

 xxix. 319. 



5. Variations in the Composition of the Atmosphere. — Mr. Dalton 

 states that he has found the oxygen in the atmosphere vary from 

 20.7 per cent, to 21.15 per cent. The latter was the case on the 

 8th of January last, the barometer being 30.9, wind N. E.. and 

 very moderate, after three days of calm and gentle frost. The 

 general state of the atmosphere yields only 20.7 or 20.8 per cent, 

 of oxygen. — Ann. Phil. N. S., x. 304. 



6. Action of Carbonic Acid on Hydrosulphurets. By M. Henry, 

 jun. — Although M. Chevreul had shewn that carbonic acid is ca- 

 pable of decomposing the hydrosulphurets ; yet, when M. Henry 

 advanced the opinion that the sulphuretted hydrogen, disengaged 

 from the mineral waters of Enghien, was owing to the action 

 of free carbonic acid on the hydrosulphurets contained in those 

 waters, it met with considerable opposition ; in consequence of 

 which he resumed the subject, and undertook a series of experi- 

 ments with a view to elucidate it, from which he has deduced the 

 following conclusions :— 



1. Carbonic acid, in contact with the alkaline or magnesian 

 hydrosulphurets, is capable of decomposing them completely, if the 



* action be continued for a sufficient length of time. 



2. The decomposition is effected either by boiling a hydrosul- 

 phuret in water impregnated with carbonic acid ; or by placing the 

 mixture, without heat, in the vacuum of an air-pump; or by 

 passing a current of carbonic acid gas through a diluted solution 

 of the hydrosulphuret. 



3. The hydrosulphurets, obtained by converting sulphates into 

 sulphurets by carbonaceous matter, are less readily acted on. 



4. The result of the decomposition of all these salts is the pro- 

 duction of carbonates, or rather bi-carbonates ; and the quantity 

 of sulphuretted hydrogen disengaged is proportionate to that of 

 the carbonate formed. — Ann. Phil. N. S., x. 381. 



7. Inspiration of Inflammable Gas. (Hydrogen 1) By Signor 

 Giacomo Cardone. — This experiment was made in consequence 

 of the difference of opinion on the effects of this gas on the 



