144 Remarks on Formic Acid. 
acid alone, which would simplify the process very materially, but 
such a result can hardly be looked upon as quite accurate, notwith- 
standing M. Gobel’s strong recommendation, because the formic acid 
is very volatile, and a portion must, therefore, always escape decom- 
position. 
‘From what has been sciadeteod upon the decomposition of for- 
mates by strong sulphuric acid, it will appear obvious that chemists 
possess an easy, direct, and certain method for obtaining oxide of 
carbon, uncontaminated by carbonic acid. 
In many operations of pharmaceutical chemistry, great advantage 
might be taken of the remarkable properties of formic acid ; for, by 
its power of removing oxygen, it is capable indirectly of deepaipids 
sing chlorides, which of course contain not a particle of this element. 
The fact is shown by the promptness with which, by simple ebulli- 
tion, it changes corrosive sublimate into calomel, the process being 
at once so easy and satisfactory as to have induced Dobereiner 
strongly to recommend its adoption ; and the rationale will be intel- 
ligible by referring the result to the combined agency of the chlorine 
for hydrogen, and the oxide of carbon for oxygen, both of the ele- 
ments of water being derived from a portion of this fluid, present at 
the time, and either existing free, or being a constituent of the for- 
mic acid itself. 
An agent which can thus promptly act upon metallic solutions, so 
as to effect reduction, is at once so peculiar and useful to persons 
engaged in chemical operations, that it only requires to be cheap in 
order to become extensively employed. ‘This, I am satisfied, may 
be made the case. 
The conversion of the formiate of ammonia into prussic acid, by 
simple exposure to heat, and the facility with which the latter yields 
formic acid when under the influence of strong muriatic or sulphuri¢ 
acid, are peculiarities well worthy of attention, and have been dis- 
tinctly brought to notice by M. J. Pelouze.* Formate of ammonia 
has, in fact, the composition, exactly, of an atom of prussic acid, 
combined with three atoms of water, and, when exposed to heat so 
as to separate the water, actually furnishes hydrocyanic acid of great 
strength ; but it is not the less remarkable that the same formate of 
ammonia, even in very large doses, as was shown by M. 
produces no injurious effects upon animals, neither does it occasion 
the en of Prussian blue. The cyanide of potassium, which 
¥. Annales. de Chim. Dec. 1831. 
