Translatwns and abstracts from the French. 239 



It dissolves in both nitric and sulphuric acid, by heat, but 

 undergoes no change of properties even if those acids are 

 boiled down upon it. Neither nitrous nor sulphurous acid 

 gases are disengaged, and the cyanic acid remains without 

 the least alteration, perfectly crystallized, in plates of the 

 purest whiteness. These are remarkable evidences of its 

 stability. 



With potassium it combines, forming potash and a cyanu- 

 ret of potassium, which produces a blue color with the sul- 

 phate of iron and an acid. 



It unites with bases, producing salts, some of which are 

 perfectly characterized by their crystalline forms, and by in- 

 teresting chemical properties. 



It appears to have no decided effect on the animal econ- 



Cyanic acid is obtained, by submitting to slight ebuUition, 

 perchloride of cyanogen in much water. As a portion goes 

 off with the vapor of the water, before it is converted into 

 hydro-chloric and cyanic acids, it is best to use at first a bal- 

 loon with a long neck, in order to condense and throw back 

 what may be volatihzed, until the entire disappearance of 

 the solid substance and the odor pecuhar to it. The fluid, 

 being then a mixture of hydro-chloric and cyanic acids, is 

 to be gently evaporated in a porcelain capsule, almost to 

 dryness, in order to expel the greater part of the hydro- 

 chloric acid. The cyanic acid begins to crystallize at the 

 commencement of the evaporation, in the midst of the hydro- 

 chloric. It is to be washed on a filter, with a little cold 

 water to remove the last portions of the hydro-chloric acid, 

 till the washings give only a slight precipitate with nitrate of 

 silver, soluble in nitric acid, and insoluble in ammonia, not 

 in excess, which, on the contrary increases the precipitate. 

 It must be redissolved in hot water, filtered and evaporated 

 to a certain point, and on cooling the cyanic acid separates 

 in small rhomboidal crystals, transparent and very pure. 



The analysis of this substance has rigorously confirmed 

 the composition presumed from that of the perchloride of 

 cyanogen, which gives rise to it. 



It is formed of 



Cyanogen, - - - - 0.6189=1 atom, 

 Oxigen, ... - 0.381 1=2 atoms. 



1. 



