384 



and could not be obtained in a crvstalline condition, bnt was, however, prepared 

 in a pure form by repeated precipitation of the soda salt in cold aqueous solution. 



The method of separation of these resin acids with dilute alkaline solvents 

 was not found to be satisfactory with either the resin of Agathis robusta or with that 

 oi Araitmria Citjutinghamii , and the method was abandoned, because on purifying 

 and analysing the portion of resin insoluble the second time in ether, this was 

 found to consist almost entirely of an acid, the potassium salt of which was insoluble 

 in excess of alcoholic potash, and that it melted at about 233° C. We did not 

 succeed in isolating an acid with alkaline solvents, having a higher melting point 

 than 200° C, so that this was evidently not quite free from admixture with the 

 acid of lower melting point. It was also found that the remainder of the acid 

 whose potassium salt was insoluble in excess of alcoholic potash, could be isolated 

 from the resin soluble in ether the second time, after the neutral bodies and oily 

 constituents had been removed by ether. On analysing this acid, results were 

 obtained which agreed with those given by the acid at first insoluble in ether' 

 and it was undoubtedly the same resin acid. The small amount of oil present, 

 together with the neutral bodies, had evidently assisted largely towards the solution 

 in ether of the second portion of this acid. 



Both these resin acids were dextro-rotatory, the one of higher melting 

 point having the higher rotation. The neutral portion was also dextro-rotatory. 

 The acid of higher melting point was not very readily soluble in alcohol, if at all 

 dilute, and was practically insoluble in chloroform and in ether. The acid of low 

 melting point was completely and readily soluble in 70 per cent, alcohol in the 

 cold, and in organic solvents generally. The acid of higher melting point appears 

 to be the next higher homologue but one, from the acid of lower melting point. 



The Queensland kauri, Agathis robiista, is botanically allied to the 

 New Zealand kauri, Agathis (Dammara) australis, and the other species of 

 Agathis of the South Sea Islands; the constituents of their resins might, therefore, 

 be expected to show some similarity of composition. Tschirch and Niederstadt 

 ("Arch. d. Ph." 239, 1902, p. 145) have investigated the resin acids occurring in a 

 specimen of recent fossil kauri resin from New Zealand. (See also Tschirch, " Die 

 Harze und die Harzbehalter,"' p. 725. They isolated from this resin an acid(kauric 

 acid) melting at 192° C, which was dextro-rotatory, the formula being C,<,H,60,. 

 The resin, however, consisted principally of acids of low-melting point, and to 

 which they give the formulae Cy,U,„0.,. The principal resin acid isolated by us 

 from the resinous portion of the oleo-resin of Agathis robusta had also a low-melting 

 point, similar to that of the main eicids isolated by Tschirch and Niederstadt 

 from the New Zealand kauri resin, but all our rcsulls with this acid of low- 

 melting point, obtained from Agathis robusta, indicated the formula to be CjuH.,iP._^, 

 and that its molecular weight was 304. The acid of high-melting jioint from 

 Agathis robusta melted at 234-235° C, was dextro-rotatory, and had a molecular 



