﻿512 



Dr. T. Ewan on the Rate of Oxidation 



No attempt was made to measure the absolute velocity of 

 the reaction, as this would have involved the accurate mea- 

 surement of the area of the surface of the phosphorus. The 

 constants obtained are therefore different in each experiment, 

 The temperature varied irregularly between the limits given. 



Table II. — Phosphorus and Oxygen. 

 (Saturated with aqueous vapour.) 



Temperature = 9°'l to 9°*2. 



Pressure of aqueous vapour . =8*6 millim. 

 „ phosphorus-vapour = 0046 millim. 



„ nitrogen . . . = 3*4 millim. 



Time in minutes 



Total pressure in 



Partial pressure 



K. 



from beginning 



mm. of mercury. 



of Oxygen. 



Calculated from 



= t. 



P. 



P- 



equation 2 b. 







94-3 



82-3 





83 



43-7 



31-7 



16-2 



96 



38-4 



26-4 



157 



1245 



27-1 



151 



15-3 



152 



2V2 



9-2 



14-2 



169 



18-0 



60 



13-9 



195 



14-7 



2-7 



13-4 



236 



131 



11 



12-2 



Temperature = 20°'2 to 20°' 7 



Pressure of aqueous vapour . = 17*6 to 18*2 millim. 



„ phosphorus- vapour = 0*116 millim. 



t 



P. 



Press 

 Nitr 



3 



ure of 

 ogen. 



V- 



K. 







750-7 



7-5 



695-6 





22 



750-7 



>> 



695-6 



00 



50 



7496 





694-5 



006 



80 



745-8 



a 



690-7 



0-18 



171 



736-5 



>j 



681-3 



077 







736-5 



j» 



6806 





255 



671-0 



»> 



615-3 



2-39 







601-6 



33-4 



549-9 





57 



5427 



-•> 



4910 



9-79 







487-7 



30-1 



439-4 





30 



4572 



» 



408-9 



9-86 







397-8 



26-2 



353-4 





25 



372-3 



>> 



327-9 



995 



The pressure was artificially reduced from time to time by pumping out 



part of the gas. Old apparatus used in this experiment and in the next. 



