Eobertson. — Fatty Acids and their Esters, dc. 577 



The reason why the melting-point curve of the product 

 from the second, coil falls more slowly is because stearone 

 tends to collect in the first coil, as it is less volatile than the 

 stearic and oleic acids. 



Towards the end of the operation the amount of oleic acid 

 appears to be constant, but it is probable that some decom- 

 position products, unsaturated in nature, are formed. This 

 decomposition appears to be intimately connected with the 

 unbearable smell which always becomes noticeable when the 

 stearone is formed. 



Art. LXL— The Association of the Fatty Acids and their 

 Esters, and the Arrangement of Atoms in Space. 



By P. W. Eobertson. 



[Read before the Wellington Philosophical Society, 7th October, 1903.~] 



In a previous communication* were given the results of cer- 

 tain investigations on the association of the fatty acids in phenol 

 solution. The work has been continued, and the normal 

 fatty acids have been studied in greater detail. The results 

 obtained for these compounds are given in Table I. The 

 number of carbon atoms in the molecule is denoted by N, and: 

 A represents the rate of association of the acid. 



The rate of association of the acids with an even number 

 of carbon atoms falls to a minimum at the sixth member, and 

 then gradually rises with increase of molecular weight. The 

 association of the earlier members has been shown to be due 

 to the influence of the carboxylic group in the molecule. 

 Some other explanation, however, must be given for the 

 association of the higher fatty acids. An investigation of 

 some closely related substances shows that the rapid rate of 

 association is caused by a long chain of carbon atoms. The 

 main grounds for this conclusion are as follows : — 



* Trans. N.Z. Inst., 1902, p. 452. 

 37— Trans. 



