TRANSACTIONS OF WAGNER 

 104 



CATALYSIS IN THE INORGANIC FIELD 



Other analogous instances of intermediate compounds in catalytic changes 

 might be cited, but after all there would remain quite a number of such 

 changes not readily accounted for in this way. The method of catalytic action 

 is an open question, which for its solution will require time, experience, and care- 

 ful investigation. 



The following experiments were performed in the course of the lecture: 



1. To illustrate negative catalysis, illuminating gas containing ethylene was 

 mixed with air and passed into a Hempel phosphorus pipet. No oxidizing action on 

 the phosphorus was indicated, either by phosphorescence or fumes. The gas-mix- 

 ture was then transferred to an absorption pipet containing bromin- water to remove 

 the ethylene, after which it was once more passed over the phosphorus, when fumes 

 and phosphorescence became at once marked. According to Winkler, minute 

 amovmts of ethylene act in this way as negative catalyst, preventing the oxidation of 

 the phosphorus. 



2. A thin platinum dish was held over a bunsen flame until red hot, the flame 

 was then extinguished, but the gas allowed to flow. The dish continued to glow, be- 

 cause the gas burned, without flame, in contact with the platinum. 



3. Hydrogen peroxid solution (3%) was poured onto manganese dioxid; gas 

 was rapidly evolved by the catalytic action of the dioxid, and being tested with 

 glowing splinter of wood was shown to be oxygen. 



4. A dilute solution of potassium iodid was acidified with acetic acid, treated 

 with hydrogen peroxid solution and starch paste, and the mixture divided into two 

 portions. To one of these, ferrous sulfate was added. The characteristic starch- 

 iodin reaction appeared at once in this portion, because the ferrous salt acted as a 

 catalyst. The other portion very slowly developed the blue. 



5. A dilute, cold mixture of solutions of oxalic acid and potassium permangan- 

 ate was divided into two portions. To one a small amount of manganous sul- 

 fate was added; the color of the Hquid was promptly discharged by reason of the 

 decomposition of the permanganate, while it persisted for a long while in the por- 

 tion to which no manganous salt had been added. 



The following lantern slides were shown in the course of the lecture: 



1. Diagram of a complete plant for Deacon's process. 



2. Diagram of details of construction of "decomposers" in Deacon's process. 



3. Diagram of a complete lead chamber plant for manufacture of sulfuric acid. 



4. Diagram of details of the lead chamber and its immediate attachments. 



5. Diagram of a complete contact plant for sulfuric acid. 



6. Diagram of the details of the contact apparatus. 



7. Diagram of the Haber apparatus for the catalytic process of making ammo- 

 nia from hydrogen and nitrogen. (See page 12.) 



