476 Transactions. — Chemistry and Physics. 



this is for the fatty acids in phenol, the association of which 

 compounds reaches a maximum at about the twelfth member. 



"When, as in B, the data are divided into two sets the 

 point under consideration is reached early in the one series, 

 and generally much later in the other. Almost always the 

 position for the first of the changes occurs in the neighbour- 

 hood of the compound with a chain containing five carbon 

 atoms. This is in accordance with the stereo-chemical con- 

 clusion that a chain of this length returns on itself. 



In all the examples enumerated under B, except that of 

 the differences of the boiling-points of the alcohols, the data 

 for the series alternately increase and decrease as the mole- 

 cular weight increases. Further, in two out of the four 

 examples in A a probable connection is shown. From this 

 we arrive at the general result. 



" In all cases where we find a maximum or minimum in the 

 physical properties of a series, either by taking each member in 

 turn or by taking alternate members, the data for that series, 

 either for the same or a closely related property , is found to rise 

 and fall alternately." 



Again, whenever the series dealt with referred to the liquid 

 or gaseous state evidence of molecular association has been 

 forthcoming. Consequently we obtain the second conclusion : 

 " A maximum or minimum in a series is due to the molecular 

 complexity of one or more members of that series." 



Art. LVIII. — A Contribution to the Chemistry of Colophony. 

 By T. H. Easterfield and G. Bagley. 



[Read before the Wellington Philosophical Society, 18th March, 1903.] 



Colophony, or common rosin, is one of the cheapest of all 

 organic preparations. It is the residue which remains in the 

 still when crude turpentine is being worked into oil or spirit. 



Colophony has been investigated by numerous chemists ; 

 nevertheless, many points in the chemistry of the substance 

 remain to be cleared up. It is, moreover, unfortunate that 

 several investigators have published statements which have 

 not been confirmed by subsequent workers, so that a mere 

 perusal of the literature is not sufficient to separate the facts 

 from the fiction. 



The following facts are in general accepted amongst 

 chemists : — 



