302 Intelligence and Miscellaneous Articles. 



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several days, and the acid was then reduced to427. At the beginning 

 of February the frost recommenced, and in the middle of the month 

 the ground was frozen to the depth of eight inches ; the carbonic acid 

 rose to 452, it then thawed and the acid was reduced to 3*66. 



The mean result of numerous experiments showed that the quantity 

 of carbonic acid in 10,000 of air was less when taken over the lake of 

 Geneva than at Chambeisy in the proportion of 4*39 to 4*60. 



It was also found that the variations in the quantity of carbonic 

 acid dependent upon season and night and day, occurred also in the 

 air taken over the lake. 



On comparing the quantity of carbonic acid found in the air of Ge- 

 neva with that of Chambeisy, the former was found to be greater in 

 the proportion of 4*68 to 4*37 ; these were the mean results of many 

 experiments. It was also found that the quantity of carbonic acid is 

 greater during day in the city than in the country, that the variations 

 occasioned by the seasons are analogous, and that the quantity of 

 carbonic acid increases more by the influence of night in the country 

 than in the town. 



On comparing the quantities of carbonic acid found in the air of the 

 plains with that of the mountains, it was observed that the latter con- 

 tained the most ; this difference is explained by the consideration that 

 the decomposition of the acid occurs principally where vegetation is 

 most abundant, as it is in the plains, and that the gas is absorbed by 

 the earth there, because it contains more rain-water. It appears also 

 that the night has but little influence in increasing the carbonic acid 

 of the mountain air. 



ARSEN1URETS OF HYDROGEN. 

 M. Soubeiran concludes from his experiments on these compounds, 

 that in the present state of science only two arseniurets of hydrogen 

 are known ; one is solid, and is composed of 



Arsenic 97 416 



Hydrogen 2-584 



100- 

 These proportions are considered by M. Soubeiran as equivalent to 

 1 atom arsenic + 2 atoms hydrogen ; but if the atom of arsenic be 

 38 and that of hydrogen 1, then it will be constituted of one atom of 

 each ; this is the hydruret of arsenic. The other compound is gaseous, 

 and is composed, according to M. Soubeiran, of 1 atom of arsenic-f 3 

 atoms hydrogen j or 



Arsenic 96*18 



Hydrogen 3*82 



100- 



If however the atom of arsenic be reckoned 38, then arseniuretted 



hydrogen gas consists of 2 atoms arsenic 76, and 3 atoms hydrogen 3. 



This gas is always the same by whatever process it may have been 



procured, except an admixture of hydrogen. It is best prepared and 



with the greatest certainty by acting with acids upon arscniuret 



of 



