186 Notice of some Recent [March 



sulpho-cyanodide of potassium. The composition of the 

 hydro-sulpho-cyanate of ammonia is analogous with that of 

 urea, sulphur being substituted for the oxygen of the 

 latter. When heated, the first effect is to disengage a con- 

 siderable quantity of ammonia, then sulphuret of carbon, 

 and soon sulphuret of ammonia appears in the neck of the 

 retort. After the distillation is over a new substance is 

 observed in the retort, mixed with chloride of potassium 

 and sal-ammoniac. By washing, the salts are taken up, 

 and the grey matter called melam, which remains, is inso- 

 luble in water, ether, and alcohol. It is frequently mixed 

 with a little sulphur, which may be removed by levigation. 

 It is decomposed by a strong heat into ammonia, cyanogen, 

 and azote. If it is boiled in potash it readily dissolves, and 

 the filtered liquor deposits a white granular matter, which 

 is melam in a state of purity. Analyzed by means of oxide 

 of copper, melam yielded, 



Carbon . . . 30*550 

 Hydrogen . . 3-860 

 Azote .... 65-589 



100-000 



When boiled with nitric acid it dissolves, and crystals of 

 cyanuric acid are deposited on cooling. Fused with potash, 

 cyanic acid is formed. Boiled with a solution of the same, 

 and concentrated, it deposits crystals. The supernatant 

 liquor retains a trace of this substance, which is precipitated 

 by sal-ammoniac or carbonate of ammonia, affording a white 

 gelatinous product, identical with the substance procured 

 by treating melam with muriatic acid. 



3. Melamine. — By this name Liebig distinguishes the 

 substance which has just been described. To obtain it in a 

 state of purity, he recomends taking the residue after the 

 distillation of 2 lbs. sal-ammoniac, and 1 lb. sulpho-cyanodide 

 of potassium, and adding to it a solution of 2 ounces of 

 potash in 3 or 4 of water, and boiling them until the liquid 

 be quite clear ; after which it is to be filtered and evapo- 

 rated gradually, when crystals of pure melamine are 

 deposited. These crystals are octohedrons, with a rhombic 

 base, in which the angles are about 75° and 115°. They 

 are white, contain no water, and are not altered by the air. 



