556 



The compomid CON,H, . (COOH), . H,0 ^}, of which the prepara- 

 tion is rather peculiar, was not found at this temperature. 



Urea-Acetic acid-Water, 



At 16°,5, 30° and 32° was found in addition to urea the compound 

 CON.H, .(CH3.COOH),. 



This compound, which melts at about 35°, is very soluble in 

 water, and is not dissociated by water. 



Urea-Hydrochloric acid-Water. 



At 20° were found, in addition to urea the two salts 



(CON3HJ, . HCl. n and CON.H, . HCl. ') 



Both salts are soluble in water without dissociation. 



Urea-Nitric acid-Water. 



At 20° the solid phases urea and the salt 



CON.H, . HNO,. 



were found. 



The solubility of this nitrate is very small and decreases as the 

 amount of HNO3 in the solution increases, until at about 707o nitric 

 acid a minimum is reached. In nitric acid solutions of about 747o 

 the nitrate is completely decomposed. 



Urea-Sulphuric acid- Water. 



At 20° the solid phases urea and the two salts 



(CON.HJ, . H,SO, and CON.H, . H,SO,. 



were found. 



The compound which Hantzsch") has obtained in all probability, 

 viz. CON2H4 . (H.SOJ,, was not found at this temperature. 



These researches are continued at other tempeiatures as well as 

 with other acids. 



Leiden, Inorganic chemical laboratory. 



1) LiuBAWiN A. Spl. 8, 83. 



2) Dessatgnes. J. 1854, 677. 



3) Erdmann. J. pr. Gb. 25, 50G (1842). 



•I) Hantzsch. Z. fur ph. Cli. Ü1, 280, i299 (1C08). 



