MR. H MKKKKTON I:\KKU <>.\ O>MWSTK>N' 



DUIKD OXYGEN. 



a tube of fused calcium chloride, and from carbon dioxide by a wash-bottle of strong 

 potash. The purified charcoal was placed in a thick, hard glass tube (fig. 4) : with 

 this was connected an apparatus for analysing the gases by weight tiimil.-ir to that 

 used in the last experiment. Instead of the conducting tube dipping under mercury, 

 a wash-bottle, not shown in the diagram, was connected with the last set of potash 

 bulbs. This contained a solution of pyrogallic acid. A small tube of potash solution 

 was placed upright in the bottle. By tilting the flask, and so upsetting the potash 

 into the pyrogallic acid, it could be seen at any moment of the experiment whether 

 all the oxygen was being used up by the carbon. 



The carbon dioxide produced by the combustion is absorbed in bulbs A. Bulbs 11 did not increase- in 

 weight, showing that the absorption in A was complete. Bulbs C absorb the carbon dioxide formed 

 by the carbon monoxide produced in the combustion. 



The air was drawn through the whole apparatus by means of a water pump. Tin- 

 rate was kept constant, so that 30 bubbles per minute passed through the bulbs. 



Experiment I. The temperature of the carbon was about 500. It was regulated 

 so that some lead chloride placed in a similar tube by the side of the carbon tube was 

 just melted. 



Percentage of carbon dioxide produced . . . 88'2 

 ,, carbon monoxide 117 



Experiment II. Temperature of carbon rather lower. 



Carbon dioxide 



Carbon monoxide 



99-9 



82-1 



17'8 



99-9 

 Experiment III. Temperature of carbon about 400 (m.p. of lead iodide). 



Carbon dioxide . 

 Carbon monoxide 



63'24 

 3676 



100-00 



4 F. : 



