UREA. 



105 



TABLE 85. ACETAMIDE. 



UREA. 



The observed molecular depression produced by urea does not change 

 appreciably with the concentration, as is seen in table 86. When these values 

 are corrected for specific gravities, the true molecular lowerings decrease 

 quite markedly with increase in the concentration of the solutions. This is 

 seen in column L' under "Hydrates," table 86. Here, again, we have consider- 

 able polymerization, and the amount of the polymerization increases with the 

 concentration of the solutions. The curve for urea is given in fig. 59. 



TABLE 86. UREA. 



CHLORAL HYDRATE. 



The freezing-point curve for chloral hydrate (fig. 59) is somewhat remark- 

 able. It shows one or two well-defined breaks, the meaning of which is 

 not apparent. While the observed molecular lowering increases quite 

 markedly with the concentration (" Freezing-point measurements," table 87), 

 the corrected molecular lowering, L' (hydrates table 87), shows only slight 

 increase as the concentration of the solution increases. The true molecular 



