190 Notice of some Recent [March 



by chlorine, and which is mixed with chloride of potassium, 

 be well washed and boiled with nitric acid, it dissolves 

 gradually, and the liquid on cooling deposits colourless 

 and transparent octahedrons with a square base, which 

 consist of pure cyanilic acid. To accelerate the decomposi- 

 tion of the salt of potash, it is advantageous to add twice 

 its weight of common salt. At first chloride of sulphur 

 distils over, and latterly long needles of chloride of cya- 

 nogen are deposited in the neck of the retort. The yellow 

 residue is carefully washed and dissolved in nitric acid. 

 The new acid is more easily soluble in cold water than 

 cyanuric acid. The crystals contain water which they lose 

 by heating, to the amount of 21 per cent. Its composition 

 is, Carbon .... 28-185 



Azote .... 32-640 

 Oxygen. . . . 36-874 

 Hydrogen . . . 2*300 



100-000 

 which Liebig considers equivalent to 6 atoms of each. To 

 determine the atomic weight of the acid, a portion was 

 neutralized by ammonia, and precipitated by nitrate of 

 silver. 93*3 cyanilate of silver afforded 54*5 chloride of 

 silver. 58*2 after being exposed to a red heat, left 26-4 silver. 

 Hence, the atomic weight of the acid is 16-25 or double 

 that of cyanuric acid, which it very much resembles in its 

 properties. Cyanilic acid is converted into cyanuric acid 

 by dissolving it in sulphuric acid, adding water and crystal- 

 lizing. All the cyanurates and cyanilites are decomposed 

 when they are crystallized in an acid liquor; the bases 

 remain in solution, and the crystals which are formed are 

 cyanuric acid or cyanilic acid. In precipitating the nitrate 

 of silver by cyanilate of potash, Liebig obtained a substance 

 which had precisely the same composition as cyanurate of 

 silver, from which it would appear that the alkalies can 

 change cyanilic into cyanuric acid. 



7. Chloride of Cyanogen. — During the decomposition of 

 sulpho-cyanodide of potassium by chlorine, besides chloride 

 of sulphur, chloride of cyanogen distils over, which may 

 be separated from the former by sublimation in a vessel 

 through which a current of dry chlorine is passed . Chloride 



