82 Dr. R. D. Thomson on the Cowdie Pine Resin. 



garden, also, there is a specimen of the Dammara orientalis, 

 from which the dammara resin previously described by che- 

 mical writers is probably derived*; and on the stem of this 

 species I have also observed unequivocal proofs of the pre- 

 sence of a resin. The cowdie resin occurs in large masses, 

 from the size of the fist to a much greater magnitude. It is 

 transparent when freshly fractured ; but as it comes from New 

 Zealand, generally it is slightly opalescent, a character which is 

 said to be produced by the action of water or moisture. The 

 colour of the resin is light amber. It is easily fused, and then 

 emits a resinous or turpentine odour. A small portion of the 

 resin dissolves in weak alcohol, but the greater part remains 

 insoluble. The solution in alcohol evolves the smell of tur- 

 pentine. The resin, when agitated with hot absolute alcohol, 

 forms a fine varnish. A similar result follows its treatment 

 with oil of turpentine, which might be found valuable in the 

 arts; sulphuric acid dissolves it; and water added to the solu- 

 tion precipitates the resin in flocks. 



Resins are usually divided into two classes, and are termed, 

 according to their characters, acid and neutral resins. The 

 cowdie resin appears to belong to both of these classes. 

 When boiled with spirit a portion of the resin dissolves, and 

 there remains u white resin, which is insoluble in weaker 

 spirit, but which forms with absolute alcohol a fine transpa- 

 rent varnish. That portion of the resin which dissolves in 

 weak alcohol possesses all the qualities of an acid, forming 

 salts with metallic oxides, and is not precipitated by ammonia, 

 while the precipitate occasioned by adding water to the alcho- 

 lic solution is quite soluble in ammonia. 



The alcoholic solution of the acid portion of the resin red- 

 dens vegetable blues. I propose to term it Dammaric acid ; 

 while the residual white resin may be called Dammaran^ to di- 

 stinguish it from the Dammarin of Lecanu and Brandes. 



Entire Resin. 

 The entire resin without the action of any chemical reagent 

 was pulverized and dried at 212°, and afforded in two analyses 

 the following results: — 

 9* 

 II. 5-69 ... ... 15-565 CO 



I. 9*435 grs. gave 25*71 C0 9 and 8*73 HO 



2 



Hence we have I. II. Mean. 



Carbon . . . 74*30 74*60 74*45 



Hydrogen . 10*28 10*28 



Oxygen. . . 15*42 15*27 



100- 100* 



* Lecanu and Brandes, Thomson's Veget. Chem., p. 538. 



