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 remarked 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 decompo- 

 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 sulphuric 

 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. Kiinckel, 

 produces no injurious effects upon animals, neither does it occasion 

 the production of Prussian blue. The cyanide of potassium, which 



* Annales de Chim. Dec. 1831. 



