RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 169 



14. Alcohol Yapor. — Mcpt. 37. — Employing the same method detailed in the 

 ease of benzol, oxidation was found to occur : 



(1) At 160O (3) At 150O 



(2) " 240O (4) " 150O 



15. Xylols. — Very careful experiments with the vapors of meta-, para- and 

 ortho-xylol were tried, as it seemed possible that these three isomers might exhibit 

 different temperatures of oxidation dependent upon the position of the side chain. 

 ^o satisfactory results were obtained, however, on account of the want of constancy 

 of these hydrocarbons as regards oxidation tempeiature. 



16. Carboistic Oxide. — This gas was prepared by the action of sulphuric acid 

 upon oxalic acid. It was purified by caustic soda solution. 



Expt. 38. Palladium Asbestos. — 



CO 10 



Air 90 



Oxidation occurred at the following temperatures : • 



(1) At the melting point of potassium nitrate (339°). 



(2) " " " " " " " (339°). 



(3) (290°). 



(4) At the melting point of potassium nitrate. 



(5) Above the melting point of potassium nitrate. 



(6) At the melting point of potassium chlorate (359*^). 



Trials were also made in varying the rate of flow, and also with different pro- 

 portions of carbonic oxide and air. The results did not differ matei'ially from those 

 just cited. This gas seems to stand intermediate between methane and ethylene in 

 its resistance to oxidation. 



JExjpt. 39. Ruthenium Asbestos. — Using the same air mixture, oxidation occurred 

 at the following temperatures : 



(1) At 1940 (3) At 182^ 



(2) " 209^ (4) " 188'^ 



The preceding experiments serve to illustrate some important facts regarding 

 the oxidation of gaseous hydrocarbons. 



1. The temperature of oxidation is mainly dependent upon the solid bodies with 

 which the gas is in contact — a fact which is not new. 



2. Two phases are often, but not always, to be observed in the process of oxida- 

 tion. As the temperature rises, a point is reached at which a minute and scarcely 

 recognizable trace of carbon dioxide appears. After the slow oxidation has con- 

 tinued for some time and gradually increased during a rise of temperature of 20, 30, 



