86 Journal of Agricultural Research voi. x. no. » 



of synthetic cyanuric acid prepared by heating urea with zinc chlorid 

 by Von Walther's method (12).^ Both, when subjected to dry heat, 

 decomposed with the formation of a white sublimate and with the 

 evolution of acid vapors having an odor resembling that of glacial acetic 

 acid. Both synthetic cyanuric acid and the compound isolated from 

 soil yielded similar precipitates when treated with mercuric sulphate, 

 ammoniacal lead acetate, and alkaline barium chlorid. A hot aqueous 

 solution of either the compound from soil or synthetic cyanuric acid, 

 when rendered very slightly alkaline with ammonia and subsequently 

 treated with dilute cupric sulphate, and allowed to cool, yielded a copper 

 salt in the form of characteristic rhombic prisms of a beautiful 

 amethyst color (i, p. 1268). This copper salt, which has the formula 

 Cu(C3H2N303)2.2NH3, may be obtained from as little as 5 mgm. of cya- 

 nuric acid. When very small quantities of cyanuric acid are suspected, 

 the test is best carried out in about i c. c. of water in the presence of 

 3 to 4 drops of concentrated ammonia. Under certain conditions not 

 fully understood the test yields a copper salt which crystallizes in the 

 form of fluffy lilac needles, much paler in color than the rhombic form. 

 To further establish the identity of the substance obtained from soil, a 

 series of comparative analyses were made, using correspondingly small 

 amounts of the soil compound and synthetic cyanuric acid and their 

 respective salts. 



On analysis of the compound obtained from soil : 



0.0519 gm. of the compound crystallized from water gave 0.01105 gm. of water 



of hydration ; 

 0.0215 gm. of the anhydrous compound required 0.01252 gm. of sodium hydroxid 



for neutralization (phenolphthalein indicator) and yielded 0.00697 gm. of 



nitrogen. 

 On analysis of the synthetic cyanuric acid : 



0.04485 gm. of the acid crystallized from water yielded 0.00945 gm. of water; 

 0.0354 gm. of anhydrous acid required 0.01084 gm. of sodium hydroxid for 



neutralization ; 



0.0600 gm. of anhydrous acid yielded 0.01953 gm. of nitrogen. 



Water 

 (per cent). 



Calculated for C3H3N3O3.2H2O 21.8 



Found in compound isolated from Indiana soil 21. 3 



Found in synthetic cyanuric acid 21. 7 



Neutralization 

 equivalent 



(molecular Nitrogen 

 weight). (per cent). 



Calculated for C3H3N3O3 129. i 32.6 , 



Found in compound from Indiana soil 130. 6 32. 4 



Foimd in synthetic cyaniuric acid 130. 7 32- 55 



Hot aqueous solutions of both the synthetic cyanuric acid and the 

 compound isolated from soil, when treated with silver nitrate and sub- 

 sequently with ammonium hydroxid, yielded heavy microcrystalline 



1 Numbers in parentheses refer to "Literature cited," p. 90-91. 



