APRIL — sept. 1858.] Properties of Wood Oil. 



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species of American Copaipek.^: and the turpentines by various 

 pines and firs, are not identical, so we may reasonably conclude 

 that the wood-oils yielded by various species of Dipterocarpus are 

 not absolutely similar ; the greater or less degree of heat to which 

 the oil has been subjected in the process of extraction, may also 

 cause a variation in the properties of the product. 



What I assert here is not a matter of supposition, but at pre- 

 sent of certainty. At the Universal Exhibition of 1855, there 

 were two samples of wood-oil, the one sent from Canara, the 

 other from Tenasserim. One of these samples (I do not know 

 which) enclosed in a small white earthen pot, which in fine- 

 ness of paste was midway between stone ware and porcelain, had 

 been given by Dr. Royle to M. Delesse, the member of the In- 

 ternational Jury who had been commissioned to report upon the 

 bitumen and petroleum forwarded to the Exhibition. M. De- 

 lesse, not finding it to be what he was seeking, sent me the 

 specimen, which I judged at once must be the new copaiba an- 

 nounced by Mr. Lowe. In fact, it approached much nearer to the 

 balsam examined by Mr. Lowe than that which has been pre- 

 sented to me by Mr. Hanbury. 



The wood-oil of Mr. Hanbury has almost the liquidity of olive 

 oil ; held up to the light of the sun, it is seen to be perfectly 

 transparent, and of the colour of dark malaga wine ; seen by 

 reflected light, it appears opaque, and of an olive green. With 

 ammonia and magnesia, it behaves in a very different manner from 

 copaiba. Mixed with liquid ammonia of 22° B., in the proportion, 

 by weight, of 5 parts of wood-oil to 2 parts of alkali, it immediately 

 forms an opaque and very thick mixture, which does not alter by 

 keeping. 



It does not solidify upon the addition of a sixteenth of its weight 

 of calcined magnesia, and the two bodies separate upon repose. 



The wood-oil of M. Delesse has the appearance of a thick and 

 slightly gelatinous liquid. After having deposited a small quantity 

 of green resin which was suspended in it, it became almost trans- 

 parent : placed between the eye and the sun, it is seen to be of a 

 pure deep red : viewed by reflexion, it still appears red, but tur- 



