44 



Transaction!^. 



day, as the vessel required at least twelve hours for thorough cleaning. 

 Hence, if only one were used, an experiment could not be left to proceed 

 all night and then the same vessel used again the next day ; but with two, 

 every day could be made use of. No influence due to the first two vessels 

 was noticed, but towards the end of the series of experiments one of them 

 was broken. The new pipette showed a marked and consistent retarding 

 effect as compared with the old one. Three experiments altogether were 

 made in the new vessel, and corresponding ones in the old one, the effect 

 in each case being the same. The temperature at which each pair was 

 made was different, so that a wide range of conditions was covered. 



The first of the following pairs of experiments quoted was made in the 

 new vessel and the second in the older vessel. 



Partial pressure of nitrogen =31 mm. 

 Partial pressure of acetic acid = 35 mm. 



Partial pressure of nitrogen = 32 mm. 

 Partial pressure of acetic acid = 35 mm. 



The second pair of experiments was made at 48-2° C. The same general 

 effect is noticeable — namely, a fairly rapid falling-off of the speed of the 

 reaction in the new vessel, and a much smaller value of K' than with the 

 old vessel. 



Partial pressure of nitrogen — 27 mm. 

 Partial pressure of acetic acid =51 mm. 



