BALSAMUM DIPTEROCARPI. 91 



may regard it as a hydrate of abietinic acid, the chemical behaviour of 

 which is perfectly analogous. Gurjunic acid is soluble in alcohol 0838, 

 but not in weak alcohol ; it is dissolved also by ether, benzol, or sulphide 

 of carbon (Werner). 



In copaiba from Maracaibo, Strauss (1865) discovered Metacopaivic 

 Acid which is probably identical with gurjunic; the former, however, 

 fuses at 206° C. 



The amorphous resin forming the chief bulk of the residue of the 

 distillation of the balsam, has not yet been submitted to exact analysis. 

 We find that after complete desiccation it is not soluble in absolute 

 alcohol. A crystallized constituent of Gurjun, which we obtained from 

 a balsam of unknown origin, has been shown^ to answer to the formula 

 Q2SJJ4602 Its crystals, belonging to the asymmetric system, melt at 

 126" — 130°C.; they are entirely devoid of acid character. A comparative 

 examination of the product of each of the above named species of 

 Dipterocarpus would be highly desirable. 



Commerce — Gurjun balsam is exported from Singapore, Moulmein, 

 Akyab and the Malayan Peninsula, and is a common article of trade 

 in Siam. It is likewise produced in Canara in Southern India. It is 

 occasionally shipped to Europe. More than 2000 lb. were offered for sale 

 in London under the name of Fast India Balsam Capivi, 4th October 

 1855; and in October 1858, a no less quantity than 45 casks appeared 

 in the catalogue of a London drug-broker. It is now not unfrequent 

 in the London drug sales. 



Uses — In medicine it has hitherto been employed only as a substi- 

 tute for copaiba, and chiefly in the hospitals of India. 



In the East its great use is as a natural varnish, either alone or 

 combined with pigments ; and also as a substitute for tar as an applica- 

 tion to the seams of boats, and for preserving timber from the attacks 

 of the white ant. To the first application it is often made better 

 appropriated ^ by boiling it, so that the essential oil is evaporated. 



Wood Oil of China — The oleo-resin of Dipterocarpus must not be 

 confounded with the so-called Wood Oil of China, which is of a totally 

 different nature. The latter is a fatty oil expressed from the seeds of Aleu- 

 rites cordata Miill. Arg. (Dryandra cordata Thunb. Elaeococca Veimicia 

 Sprgl. Prodromus xv. part 2, p. 724), the well-known Tung tree of 

 the Chinese. It is a large tree of the order Euphorbiacece, found in 

 China and Japan. The oil is an article of enormous consumption 

 among the Chinese, who use it in the caulking and painting of junks 

 and boats, for preserving woodwork, varnishing furniture, and also in 

 medicine. In the commercial reports of H.M. Consuls in China (No. 5, 

 1875, p. 3, 26) we find that this oil is largely exported from Hankow : 

 199'654 peculs in 1874, and forms an article of import at Ningpo : 15123 

 peculs in 1874 (pecul=133"33 lb. avoirdupois). It is, however, not 

 shipped to foreign countries. The oil of the 'Tung tree is also ex- 

 tremely remarkable on account of its chemical properties as shown 

 by Cloez (1875—1877). 



1 Fluckiger, PAarw. Journ. (1878) 725, with ' Catalogue of the French Colonies, Paris 

 fig. Exhibition, 1878, 101, quoted above. 



