CATALYSIS: THE GUIDE OF LIFE 95 



forces of molecules exert powerful attractions or repulsions on particles 

 which come within the range of attraction. 



"If we consider a single molecule, or a very small molecular group, 

 A, it is obvious that the residual electrostatic or electromagnetic sur- 

 face forces present to the milieu a mosaic which is highly specific 

 in various directions. In Fig. 9 the specific nature of the surface of A 

 is shown diagrammatically by the convention of specific jaggedness in 

 the outline. In consequence of its mosaic pattern, a particle may 

 exhibit several different kinds of specific actions separately or simul- 

 taneously, on different portions of its periphery. 



"Let us now imagine a simple molecule, B, approaching A, and the 

 process of fixing itself at the surface. This will occur only if the 

 surface charges presented by the approaching molecule bear a lock- 



A h At& AS G. 



Ctjj © 



Figure 9 



and-key relation to those of the particle, and if the velocity of approach 

 lies within critical limits. 



"As soon as the oppositely charged areas come within their critical 

 distance, fixation occurs, as is diagramed A+B. Instantaneously 

 thereafter occurs a mutual neutralization of forces and a complete 

 reshuffling of all the internal and surface fields. The compound 

 molecule, after the fixation, will present to the milieu a different 

 configuration from what it presented before fixation. This is dia- 

 gramed as AB. The former B portion might now be able to make 

 other attachments previously not possible to it. The attachment of 

 a second molecule, C, would once more cause a reshuffling of all the 

 fields involved, as is diagramed ABC. Now, if the resulting bond 

 between the two added molecules were stronger than the bond be- 

 tween the former A and B portions, then there might be released 

 to the milieu a new type of duplex molecule, BC, while the fixation 

 surface of A would be freed for renewed action. 



"Suppose now that we have a catalyst particle composed of several 

 simple molecular subunits which we can diagram roughly as A in Fig. 

 10. Suppose that at some one of its faces the catalyst fixes or absorbs 



