1COO CYANOGEN COMPOUNDS. 



gas, and the liquid yields on evaporation, colourless, anhydrous 

 octohedrons of cyanilic acid, which has the same composition 

 as cyanuric acid, and also crystallizes from water with 4HO. 

 The nitric acid after its action on mellon contains ammonia; it 

 is the only acid which causes mellon to undergo this transfor- 

 mation. 



Boiling potash ley dissolves mellon with evolution of ammonia 

 and formation of a salt in white needles, which has not been 

 sufficiently examined. 



fjydro-persulphocyanic acid, CyS 3 H (Woskresensky ;) a 

 yellow matter insoluble in water, formed when sulphocyanide of 

 potassium heated to fusion is exposed to a stream of dry hydro- 

 chloric acid. It is soluble in boiling alcohol. 



Melam, Cj 2 N n H 9 (Liebig), one of the products of the de- 

 composition by heat of sulphocyanide of ammonium. It is most 

 conveniently prepared by heating a mixture of dry sulphocya- 

 nide of potassium with twice its weight of sal ammoniac in a 

 porcelain bason, above 350 or 400, by a charcoal chauffer. 

 Ammonia, sulphuretted hydrogen and bisulphuret of carbon go 

 off, and melam remains mixed with chloride of potassium, from 

 which it may be separated by washing with pure water. Melarn 

 is a greyish white powdei, not crystalline, insoluble in water, 

 alcohol, and ether. It is decomposed by heat into mellon and 

 ammonia. 



Melamine } C 6 N 6 H 6 (Liebig) ; a salifiable base formed by dis- 

 solving melam in 1 part of hydrate of potash dissolved in 20 

 parts of water ; the mixture being kept in ebullition till the 

 turbid liquor becomes perfectly clear. One atom of melam with 

 2 atoms of water are then resolved into 1 atom of melamine 

 and 1 atom of ammeline. Melamine is deposited from the con- 

 centrated solution on cooling in anhydrous rhomboidal octohe- 

 drons, transparent, colourless or tinged slightly yellow. It is 

 very slightly soluble in cold water, dissolves to a greater extent 

 in boiling water, but its solution is very slowly effected ; it is 

 neutral to test paper, insoluble in alcohol and ether. When 

 dry melamine is strongly heated, the greater portion of it 

 sublimes without decomposition. Melamine forms crystallizable 

 salts on combining with dilute acids. 



Ammdine, C 6 N 5 H 5 O 2 (Liebig). The alkaline solution above, 

 from which melamine crystallizes, still contains ammeline dis- 



