42 CYANAMID — MANUl^ACTURE, CHEMISTRY AND USES 



a constant, a fact highly characteristic of absorption pro- 

 cesses. 



In this experiment also, the cyanamide finally disappears 

 entirely from the solution in the course of time, and hence, 

 chemical conversion occurs along with the absorption 

 phenomena. 



Taking all the above facts together, it is easy to under- 

 stand that in the initial period of contact between the cyanamide 

 solution and the soil there is a withdrawal of cyanamide mole- 

 cules from the solution, and a concentration of molecules in 



Gleams Cyart<xm/€/e app/ted 

 p6f Zoo grants so//. 



Fig. 4. 



the limiting stratum between the solution and the surface of 

 the solid soil particles. Along with and subsequent to this 

 absorption process there is a chemical conversion of cyanamide 

 molecules, by catalytic action of soil colloids, as we shall show 

 later, the products of the reaction being removed continually 

 and being replaced by new molecules of cyanamide in the limit- 

 ing stratum. 



