﻿518 



Dr. T. Ewan on the Rate of Oxidation 



Above a certain limiting pressure (which probably varies 

 with the temperature) this ceases to be true, the reaction 

 taking place very much more slowly. 



Phosphorus and Dry Oxygen. 



Turning now to the action of dried oxygen on phosphorus 

 quite a different result is obtained. 



The experiments were made by the method and with the 

 apparatus already described. The water in the glass vessel 

 at A (fig. 1) was merely replaced by phosphorus pentoxide. 

 In the first experiment the oxygen was allowed to remain in 

 contact with the phosphorus pentoxide for a week, in the 

 second, for two days. The numbers obtained are given in 

 the following Table. 



Table III. — Phosphorus and Dry Oxygen. 





Temperature = 20°«87 to 21°'26. 





Pressure of phosphorus-vapour = 



0-12 millim. 



Time in 

 minutes 



Total 



Partial 



Partial 







from the 



beginning. 



t. 



pressure. 

 P. 



pressure of 



Nitrogen. 



(a). 



pressure of 

 Oxygen. 



K v 



K. 







433-5 



56-5 



3770 







70 



433-3 















2319 



303 



201-6 







15 



231-9 



M 



201-6 







55 



231-5 



n 



201-2 







110 



230-5 



»> 



200-2 



1-23 









1220 



10-0 



106-0 







20 



1172 



, } 



101-2 



23-4 



2-31 



120 



86-2 



)} 



70-2 



27-5 



2-95 



142 



78-9 





629 



27-7 



302 



161 



71-1 



' 



551 



28-2 



3-18 



181-5 



62-2 



}J 



46-2 



290 



3-31 



192 



571 



>! 



41-1 



29-3 



3-45 



204 



504 





34-4 



30-0 



363 



218 



36-7 



J 



20-7 



32-5 



4-29 



227 



349 





189 



31-7 



4-21 



286 



260 



100 



33-0 



4-73 



253-5 



217 



5-7 



31-9 



4-83 



