452 



MESSRS. R. S. BUTTON AND J. E. PETAVEL ON ELECTRIC 



TABLE II. Oxidation of Metals in Air under High Pressures. 



Experiment No. 



A 1, 3, and 4 



A5 



A6 



A7 



A 13 



A 12 



Crucible filled with copper, iron, or aluminium, heated for half-an-hour in furnace of 

 type fig. 11, C, under carbon arc. Pressures, about 30 atmospheres. Power, 5 

 to 10 kilowatts. Metals fused, but the oxidation as shown by the gas analysis 

 was practically limited to the carbon. 



Arc between iron electrodes. Pressures, 27 to 75 atmospheres. Metal at end of 

 electrode apparently violently boiling, but after more than an hour still over 

 20 per cent, oxygen. Subsequently iron bar maintained at bright red heat by 

 current of 1000 amperes for about 2 hours without entering into combustion. 

 Oxygen at end of run over 20 per cent. 



Iron electrodes, 1 T V inches diameter, in oxygen at 15 atmospheres. Points of 

 electrodes heated by 300-ampere arc. Vivid combustion started. Current at 

 once cut off. Positive electrode continued burning until pressure was reduced to 

 5 atmospheres. Total iron burnt, 550 grammes. 



Rod of iron, inch diameter, 1J inches long, between iron electrodes in air at 

 100 atmospheres, maintained at bright red heat by powerful current and then 

 fused without starting combustion, Over 20 per cent, oxygen after run. 



High-tension arc (1000 volts) between thin iron rods. 

 Combustion not started. 



Arc between copper electrodes at 92 atmospheres, 

 oxygen. 



Pressure, 110 atmospheres. 



After run, 20-5 per cent. 



