484 Transactions. — Chemistry and Physics. 



answer to these questions that the present investigation has- 

 been commenced. 



The riniu {Dacridium C2ipresstnum) is one of the best 

 known and most widely used of the New Zealand forest- 

 trees ; its timber is highly resinous, and the heart-shakes, 

 which are frequently large, contain an opaque pinkish resin 

 which may conjpletely fill the cracks or only occur in warty 

 globules having a concentric structure. 



Eimu-resin dissolves for the most part in alcohol, but 

 leaves a small residue of a red amorphous substance, which 

 has a bitter and astringent taste. If water be added to the 

 alcoholic solution until a faint turbidity results, and the solu- 

 tion be allowed to stand for some hours, the greater part of 

 the resin separates in the form of almost colourless hexagonal 

 plates, which can be completely decolourised by recrystallisa- 

 tion from dilute alcohol. The crystalline compound thus 

 obtained is strongly acid, and the name " rimuic acid " is 

 proposed for it. 



Eimuic acid is very sparingly soluble in water, benzene, 

 and light petroleum ; easily soluble in alcohol, ether, and hot 

 acetic acid. It melts at 192°-193° C, and has the specific 

 rotation [a] d = — 150°. 



Two preparations of the acid were analysed. The analyses 

 and molecular-weight determinations agree with the formula 



Calculated for Pound. 



C16H.0O3. I. II. 



C = 738 ... 73-8 73-7 



H= 7-7 ... 7-9 7-95 



= 18-5 



1000 

 M.W. = 260 ... 266 and 288 by cryoscopic methods, 



264 by titration. 



The following salts have been analysed : — 



Acid Ammonium Salt — (CieHaoOs).^, NH3, H.2O. — This salt is 

 sparingly soluble in water ; it is readily obtained by saturating 

 a solution of ammonia with the acid, filtering at once, and 

 gently warming the filtrate. 



Calculated. Pound. 



NH,, + H,0 = 6-7 ... ... 6-3 



NH, = 314 ... ... 30 



Barium Salt — (CieHi.jO,,)^, Ba, 14 HjO. — This most charac- 

 teristic crystalline salt separates in well-developed square 

 plates when a solution of barium-chloride is added to a solu- 

 tion of the acid m excess of ammonia. Three preparations 

 gave — 



