ad 
Artificial Formation of Formic Acid. 197 
merce in water until no more carbonic acid is disengaged. 
3d, mix this solution while hot and concentrated, by a hitle 
at a time, with the former; continually stirring it until ef- 
fervescence ceases. Care must be taken not to add the 
arsenite of potash in excess. An abundant precipitate is 
formed of a dirty yellow colour. 4th, add acetic acid, (about 
three parts) or such a quantity that there may be a slight 
excess of it sensible, by its odour after the mixture ; by de- 
grees the precipitate diminishes in volume, and at the end 
small quantity of this green, it favored the production of the 
superior color, somewhat in the same manner as a cry 
attracts its kindred molecules ina saline solution. : 
The colors which we obtained by the precee method 
were judged by several persons to be more lively than that 
of Schweinfurt. 
29. Artificial formation of Formic Acid.—Dobereiner 
has discovered that when tartaric acid, or cream of tartar, 
Peroxide of manganese and water, are heated together, a 
ntity of carbonic acid 
quid acid distils, which, on superficial 
examination, might be taken for acetic, but which, on a 
nic acid, water, : t 
quently be obtained a larger quantity of the la 
best proportions of the mixture are— 
