588 MR. H. BRERETON BAKER ON COMBUSTION IN DRIED OXYGEN. 



When the tip of the oxygen tube was broken under mercury the liquid rushed in 

 and filled the tube, showing that combustion was complete. The nitrogen tube was 

 taken into a dark room, and the points of both ends broken. A current of air was 

 drawn through it with the mouth. No taste or smell was perceptible, and after this 

 treatment no luminosity appeared in the tube. A trace of ordinary phosphorus can 

 be detected in this way. We must conclude, therefore, that at this temperature of 

 260 no change takes place when amorphous phosphorus is heated in a sealed tube 

 containing nitrogen. 



LEMOINE ('Deutsch. Chem. Gesell. Berichte,' 1867) has shown that the conversion 

 of amorphous phosphorus into the ordinary modification is prevented if there is a 

 considerable tension of phosphorus vapour in the tube. Though it was scarcely 

 probable that this would exist in the tubes above described, where no taste of 

 phosphorus was found in the gas, it was thought advisable to perform two experi- 

 ments without sealing the tubes in which the phosphorus was heated. Nitrogen was 



Fig. 7. 



prepared in quantity by exposing the air in large bell-jars to the slow action of sticks 

 of phosphorus. When the sticks were no longer luminous, the nitrogen was considered 

 ready for use. In order that no vapour of phosphorus should accompany the nitrogen, 

 the gas was passed through a tube containing red-hot copper oxide. It then bubbled 

 through a solution of alkaline pyrogallate to take out the last traces of oxygen, and 

 was then passed over pure amorphous phosphorus contained in a long tube. To 

 prevent access of air a wash bottle of water was connected with the end of this tube. 

 The tube itself passed through an air bath which was fitted with a PAGE'S regulator. 



In the first experiment the air bath was kept constantly heated to 265 for three 

 hours, a slow current of nitrogen being passed through the tube. No deposit of 

 ordinary phosphorus was found on the cold part of the tube. In the second experi- 

 ment the phosphorus was kept for five hours at a temperature of 278, but not only 

 was no deposit of phosphorus produced, but, after cooling, no smell or taste of ordinary 

 phosphorus could be detected by drawing air through the tube. It is proved, then, 



