ERNST G. irUF 



219 



applying Langmuir's simple isotherm to each of a series of sites in the adsorbing 

 surface in which each type of site is characterized by a different energy of ad- 

 sorjMion. Total adsorption is then calculated by the process of summation. One 



15 20 



[k'J , ;ueq./gm 



Fig. 9. Potassium isotherms (Freundlich) in frog skin (29). 



difficulty is that of establishing the kind of energy distribution over the surface 

 that would explain the experimental isotherm. This subject has been recently 

 reviewed by Laidler (42) and Ries (61). 



