576 MR. H. BRERETON BAKER ON COMBUSTION IN UR[ED OXYGEN. 



the stopper of the third flask ; the other end was sealed. A small quantity of boiled 

 sulphuric acid was poured into the bottle through the stoppered funnel, so that the 

 pressure of the gas during its drying might be greater than the atmospheric pressure. 

 The gas was thus dried, partly by phosphorus pentoxide, and partly by sulphuric acid. 

 Since the connecting tubes were narrow, only a slow diffusion of slightly moist gas from 

 the bottle containing strong sulphuric acid could take place into the flasks. The gas 

 was thus thoroughly dried in the second and third flasks. The oxygen used in the 

 experiment was taken from this third flask, though the pressure used to drive it out 

 was derived from the sulphuric acid poured into the large bottle. The appai-atus was 

 left to dry for four days. 



Experiment I. The sealed end of the tube having been broken off under dried 

 mercury, the carbon was heated to dull redness in a stream of the dried gas. At 

 first it glowed a little. The current was stopped. A blue flame was seen to run 

 along the tube from the heated point to the end. This could only be due to carbon 

 monoxide. 



Experiment II. As it was evident that either the charcoal or the glass was not 

 quite dry, the tube, still connected with the oxygen flask, was sealed at its open end, 

 and allowed to dry for another week, gentle heat being occasionally applied. At the 

 end of this time the sealed end of the tube was broken under mercury, previously 

 dried. The part containing the charcoal was heated as before with a Bunsen burner. 

 This time no glowing was seen, although 200 c.c. of oxygen was rapidly passed over 

 the red-hot charcoal. After this a sample of 27'5 c.c. of the gas was collected. It 

 was analysed and found to contain 



c.c. Per cent. 



Carbon dioxide 1 '4 5'0 



Carbon monoxide ll'O 40 '0 



Oxygen 15'1 54'9 



27-5 99-9 



Experiment III. The apparatus was allowed to stand for another week, and then 

 the charcoal was raised to bright redness with a gas blow-pipe. No visible combustion 

 occurred ; 29 '6 c.c. of gas was collected. The analysis gave 



c.c. Per cent. 



Carbon dioxide '6 2'2 



Carbon monoxide 11 '8 39 "5 



Oxygen 17'2 58'1 



29-6 99-8 



These analyses are very striking, showing that a large quantity of carbon monoxide 

 is produced when carbon is heated in a current of oxygen, even when the oxygen is 

 in excess. They seem to point to the conclusion that carbon burns first to carbon 



