Robertson. — On certain Maxima and Minima. 471 



From analogy with the fatty acids it is to be expected that 

 the esters of these acids would exhibit similar relations. But 

 the data are too scanty and inconsistent among themselves to 

 draw any conclusions therefrom. 



The data for various aldehydes and. ketones are presented 

 in the next table, as they show a similarity to the results 

 already obtained. 



Table X. 



* This boiling-point is interpolated. 



The maximum in all cases occurs in the usual place — i.e., 

 the second member of the first set of differences. The 

 ketones of the type E. COCfL, show practically as much 

 association as the aldehydes, thus differing from the other 

 series of ketones, which is almost normal. The methyl 

 esters, it will be remembered, differed largely from the acids 

 whence they were derived ; but here the alkyl radical replaces 

 a hydroxyl hydrogen, while in the case of the aldehydes the 

 hydrogen is joined directly to a carbon atom. 



Seeing that when the gaseous molecule is associated at the 

 boiling-point results of this nature are obtained, the nitriles 

 and nitroparaffins ought to behave in a similar manner. 

 That this is the case is seen from the following tables : — 



Differences. 

 15-5 



22-5 



22 



18 



21-5 

 13-5 

 21 



Here, again, the maximum is observed in exactly the same 

 place as among the acids and their esters, the aldehydes and 

 ketones. Further, there is an exceedingly pronounced mini- 

 mum in the other series ; this corresponds to a similar mini- 



