Intelligence a7id Miscellaneous Articles, 607 



M. Frcmy, that tartaric acid may lose water and go through modifi- 

 cations analogous to those of phosphoric acid, until it becomes an- 

 hydrous tartaric acid. Paratartaric acid undergoes the same changes. 

 M. Fremy has therefore introduced into the study of the organic 

 acids a new point of view, and which is exclusively his own. He 

 seems, at first, to have decided the question concerning their nature, 

 since by discovering anhydrous tartaric acid he appears to have re- 

 moved all doubt as to the formula of this acid in the state of hy- 

 drate. But with a little attention it will be observed that these 

 new results are easily explained when tartaric acid is considered as 

 a hydracid. 



In fact, in such proportion as tartaric acid loses water, it gives rise 

 to products whose capacity of saturation diminishes until it entirely 

 ceases. For anhydrous tartaric acid is no longer to be considered 

 as an acid, and after tartrelic acid, other substances are formed 

 which have still less saturating power. 



Tartaric acid and the new acids described by M. Frcmy may be 

 regarded as distinct hydracids. As to anhydrous tartaric acid, this 

 would be a product of decomposition, but not itself an acid. These 

 theoretic views it was considered necessary to detail in order to prove 

 that the researches of M. Fr^my do not in any way destroy the 

 results given by the analysis of emetic tartar. — L'Institut, May 3, 



183S. 



ON THE ACTION OF FERMENTATION ON A MIXTURE OF OXYGEN 

 AND HYDROGEN GASES. BY M. THEOD. DE SAUSSURE. 



It is well known that the quantity of hydrogen gas contained in 

 the atmosphere does not amount to 1-lOOOdth of its volume. 

 Nevertheless the decomposition of organic matters continually adds 

 fresh quantities of this gas to atmospheric air ; on the other hand 

 there are few substances which occasion the combination of hydrogen 

 with oxygen at common temperatures; and the circumstances which 

 the combination requires, prove that the disappearance of the hydro- 

 gen cannot be accounted for in this way. M. de Saussure states that 

 he has found that the combination is effected by the fermentation 

 of organic substances universally distributed over the surface of the 

 soil, even when on account of the smallness of their quantity and 

 the slowness of their operation no rise of temperature takes place. 



By exposing fermentable bodies in pieces of the size of a nut to 

 the mixed gases M. de Saussure has arrived at the following con- 

 clusions : — The combination of hydrogen and oxygen gases may be 

 effected without inflammation at the temperature of the air, by 

 bodies submitted to slow fermentation. 



They usually produce this combination when they are accumu- 

 lated and impregnated with a sufficient quantity of water to pre- 

 vent their complete contact with the oxygen gas. If this contact 

 be made by increasing the surface of the fermentable body, or by 

 diminishing the quantity of water, the hydrogen gas is not absorbed, 

 and the oxygen gas disappears in other combinations. 



The porosity of the fermenting body greatly contributes to the 

 destruction of the detonating mixture. 



Many observations prove that the hydrogen gas which disappears 



