88 Journal of Agricultural Research voI.x.no.s 



The close similarity in the behavior of tetracarbonimid and cyanuric 

 acid may make the identification of either a difficult matter; and, if the 

 amounts of substance isolated from soil are too small for analysis, it may 

 be impossible to distinguish between the two. In a previous paper (lo) 

 from this laboratory the isolation of tetracarbonimid from a number of 

 soils was reported. The compound isolated from one of these soils (a 

 loam soil from the grounds of the Department of Agriculture) was ob- 

 tained in a quantity too small for analysis. Since, then it has been pos- 

 sible to obtain more of this compound, from the soil then examined, and 

 the supposed tetracarbonimid has been shown to be cyanuric acid. The 

 analytical data relating to this compound are given below: 



0.0564 gm. of the compound required 0.01728 gm. of sodium hydroxid for neu- 

 tralization and yielded 0.01811 gm. of nitrogen. 



Neutralization 

 equivalent 



(molecular Nitrogen 

 weight). (per cent). 



Calculated for C3H3N3O3 129. i 32. 6 



Found 130-6 32.1 



The compound from this lawn soil also yielded a rhombic amethyst- 

 colored copper compound similar in all respects to the compound obtained 

 from synthetic cyanuric acid. On analysis: 



0.02970 gm. of the copper compound prepared from the substance obtained from 



this soil gave 0.00660 gm. of cupric oxid. 



0.015995 ^ gm. of the copper compound obtained from synthetic cyanuric acid 



gave 0.003535 gm. of cupric oxid. 



Copper 

 (per cent). 



Calculated for Cu(C3H2N303)2.2NH3 17. 96 



Found in the copper salt prepared from the compound obtained 



from the lawn soil 17* 75 



Found in the copper salt prepared from synthetic cyanuric acid. 1 7. 65 



The amount of cyanuric acid isolated from 23 kgm. of lawn soil was 

 approximately 1 10 mgm. This amount corresponds to about 19.5 pounds 

 per acre-foot. 



Cyanuric acid was also isolated from three other soils. A Maine soil 

 yielded about 0.165 gm. of cyanuric acid (sample a) from 46 kgm., a 

 Florida soil yielded approximately 0.040 gm. of cyanuric acid (sample b) 

 from 23 kgm., and a Texas soil yielded about 0.040 gm. of cyanuric acid 

 (sample c) from 46 kgm. 



The following analytical data were obtained : 



0.059 gm. of crystallized sample (a) gave 0.0124 gm. of water; 



0.04785 gm. of anhydrous sample (a) required 0.01458 gm. of sodium hydroxid 



for neutralization and yielded 0.01575 gm. of nitrogen; 

 0.0328 gm. of anhydrous sample (b) required o.oio gm. of sodium hydroxid for 



neutralization and yielded 0.01060 gm. of nitrogen; 

 0.0382 gm. of crystallized sample (c) gave 0.0087 gm. of water; 



• These -weighings were performed on an ordinary chemical balance by the method of interpolation as 

 described in text books on physical measurements. 



