july — sept. 1857.] Wood Oil 



vial. After cooling, the solidification is yet more perfect ; but a gentle 

 warmth, assisted by slight agitation, restore its former liquidity. Mr. 

 Lowe has given the temperature of 230° F. for the solidification of the 

 oil : I suppose that the different temperatures noted by these two observers 

 may be accounted for by some difference in the liquids on which they 

 operated ; for as the sorts of copaiba furnished by different species of 

 American Copaiferce 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 present of certain- 

 ty. 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 fineness of paste was midway between stone-ware and porcelain, 

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

 tional jury who had been commissioned to report upon the bitumen and 

 petroleum forwarded to the Exhibition. M. Delesse not finding it to be 

 what he was seeking, sent me the specimen, which I judged at once must 

 be the new copaiba announced by Mr. Lowe. In fact, it approached 

 much nearer to the balsam examined by Mr. Lowe than that which has been 

 presented to me by Mr. H anbury. 



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 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 cal- 

 cined 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 transparent : placed between 

 the eye and the sun, it is seen to be of a pure deep red : viewed by reflec- 

 tion, it still appears red, but turbid, and resembles a liquid in which finely- 

 powdered Cochineal might be suspended. The complimentary colour of 



