CATALYSIS IN THE INORGANIC FIELD 



DAVID WILBUR HORN 

 Delivered April 24, 19 17 



CONTACT underlies chemistry. While bodies influence each other at 

 almost incredible distances, as is shown in the mutual influence of the 

 earth and the sun through a distance of about 92,000,000 miles, this 

 action is physical, not chemical. Briefly, no contact, no chemical action. 



An attempt to refine the idea of contact leads to the conclusion that con- 

 tact may be as intimate as the fineness and structure of matter will permit. 

 Undoubtedly better contact is possible between bird-shot than between can- 

 non-balls. And if contraction and interpenetration occur, better contact 

 would be realized than would be possible between incompressible and impene- 

 trable bodies. 



Such speculations are, however, scarcely warranted. These are the days 

 when the structure of the atom is in doubt, as it has, of course, always been, 

 and when the doubt is generally admitted; and it is wiser not to venture far 

 beyond experiment in speculations on energy and matter. Further, the object 

 of the present lecture is narrative and descriptive. 



Contact may conceivably be a process involving only two substances, but 

 this conception is seldom realized in practice. Even when two pure substances 

 are obtainable (if ever) we are likely to confront the problem of excluding the 

 all-pervading atmosphere with its several constituents and different foreign 

 bodies. When minimizing this source of compHcations by working in the 

 erroneously named "vacuum," our two pure substances would still be affected 

 by the presence of matter in quantities demonstrably capable of profound 

 effects, as the work in radio-active phenomena and in physiologic chemistry 

 shows. In any enclosed system the walls of the containing vessel are always a 

 part of the system and, as will be seen later, may influence chemical changes 

 radically. 



The foreign bodies present at contact of two substances may, of course, 

 be inert or active. In by far the larger number of cases studied in the develop- 

 ment of chemical knowledge the foreign body was inert or its action escaped 

 attention, therefore, the time-honored generalizations of chemistry, its "funda- 

 mental laws," refer to the action of pure substances upon each other without 



reference to the effects of adjacent bodies. 



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