Chemical Science. 233 
acetic acid, but which more careful investigation proves to be 
formic acid. 
This acid, mixed with concentrated sulphuric acid, is con- 
verted at common temperatures into water and carbonic oxide ; 
nitrate of silver, or of mercury, convert it, when gently heated, 
into carbonic acid, the oxides being at the same time reduced 
to the metallic state. With baryta, oxide of lead, and oxide of 
copper, it produces compounds, having all the properties of the 
genuine formates of those metals. 
The residue of the mutual action of the tartaric acid and 
oxide of manganese, is a mixture of formiate and tartrate of 
manganese ; they may be separated by water, which only dis- 
solves the formiate. 
If a portion of sulphuric acid be employed in the above pro- 
cess, the tartaric acid is entirely resolved into carbonic acid, 
water, and formic acid, the product of the latter being much 
increased. The best proportions are, 
2 parts of crystallized tartaric acid, 
peroxide of manganese, 
5 concentrated sulphuric acid, diluted with 
about twice its weight of water. 
M. Doebereiner remarks that in several processes in which 
the formation of acetic acid has been suspected, it is not im- 
possible that formic acid has been produced. ‘The relations 
which he has pointed out between the formic acid and sulphuric 
acid and the soluble salts of silver and mercury, whether it be 
dissolved in water or combined with a base, are sufficient to 
distinguish it from the acetic acid. Annalen der Physik, LXX). 
107. 
[The Editor of the Annales de Chimie, whence we have ex- 
tracted the above, informs us, that he has repeated the experi- 
ments and verified the conclusions of M. Doebereiner. The 
possible identity of lampic and formic acids has occurred to us, 
whilst transcribing the preceding details. ] 
11. Action of Water on Metallic Arsenic.—If water be boiled. 
on metallic arsenic, which has been previously freed from any 
adhering oxide, still the water will be.found to contain, upon 
examination, abundance of oxide of arsenic. If water be dis- 
tilled from off the metal, oxide of arsenic will pass over in solu- 
tion. These experiments indicate a decomposition of the water 
by the metal; but the hydrogen which might be expected to re- 
sult from such decomposition, has not yet been obtained. — It 
probably unites with the arsenic to form an hydruret.—T. G. 
12. Considerations on the existence and state of Sulphur in 
