>rA( i.KOi). — Hate of O.ri(]atioii of ArrldhJclnide to Acetic Acid. 45 



Partial pressure of nitrogen = 26 mm. 

 Partial pressure of acetic acid = 51 mm. 



The next pair of experiments was made at 21° C. 



Partial pressure of nitrogen = 20 mm. 



Partial pressure of nitrogen = 24 mm. 



The fact of these three sets of experiments showing a consistent differ- 

 ence in the rate of the reaction is very strong evidence that the difference 

 was due to the vessel. The conditions otherwise were exactly the same, 

 and the vessels were cleaned in exactly the same manner — namely, by 

 leaving them in a solution of potassium-permanganate and hydrochloric 

 acid for twelve hours at least, and then washing out with oxalic acid and 

 distilled water. 



4. Water-vapour. — It is extremely probable that, as water-vapour has 

 the effect of increasing the dissociation of oxygen molecules, its presence 

 would accelerate this reaction. It had been hoped that an experiment 

 might be made in which both the aldehyde and oxygen were dried abso^ 



