RICHARDS AND STULL. BROMINE AND OXALIC ACID. 337 



1. Bromine water reacts slowly upon oxalic acid at ordinary room 

 temperatures, and rapidly at higher temperatures. 



2. The concentration of the oxalic acid may be varied through wide 

 limits without seriously changing the speed of the reaction. 



3. Neutralization or the addition of salts of weaker acids immensely 

 accelerates the reaction. 



4. The addition of strong acids retards the reaction. 



5. Hydrobromic acid has a retarding effect more than ten times as 

 great as hydrochloric acid. 



6. The bromine-vapor pressure of bromine water is likewise greatly 

 diminished by the addition of hydrobromic acid or a bromide. 



7. Taking all these facts into consideration, it is shown with the help 

 of the " Law of Mass Action," and the hypothesis of electrolytic dis- 

 sociation, that the main reaction under consideration is probably the 

 following: C 2 4 " + Br 2 ±+ 2Br' + 2C0 2 ; but that this reaction is 

 greatly retarded, as the change progresses, by the conversion of some of 

 the otherwise available bromine into the complex ion Br 3 ' by union with 

 the bromine ion formed in the main reaction. 



Cambridge, Mass, U. S. A. 

 June 6, 1902. 



vol. xxxvni. — 22 



