Aleppo and Smyrna. 185 



matter. Tt contains indeed much less gum than the other 

 gum resins, but enough, however, to form a milky liquid 

 with water. 



The action of the alcoholic tincture of scammony on 

 turnsole, naturally led us to ascertain whether the property 

 of reddening this blue colour was owing to an acid. Our 

 experiments not having enabled us to acquire a direct 

 proof, we tried some resins in a comparative manner, which 

 we submitted to the following experiments. 



]. Sandarach. This resin is converted into a knotty or 

 grumous mass on being boiled with water. The filtered 

 liquor remains- clear: when properly evaporated, it slightly 

 reddens turnsole tincture: the taste is bitter : it does not 

 change the infusion of violets, is not precipitated by alco- 

 hol or by the acetate of lead ; which proves that it contains 

 neither gum nor extractive principle. It is therefore a pure 

 resin. 



The resin which had bCen treated with boiling water, 

 was dissolved in alcohol. This liquor reddens turnsole 

 tincture strongly, and has no action upon syrup of violets. 



We also digested sandarach reduced into powder in al- 

 cohol, adding to the liquor, when warmed and filtered, 

 boiling water, which precipitated the resin from it. The 

 filtered liquor was turbid upon cooling. It had the strong 

 smell of sandarach resin : its taste was bitter; and its action 

 on turnsole tincture was so weak, that we could not pre- 

 sume the existence of a free acid. 



2. Mastich. This substance presents nearly the same 

 phaenomena with the above : the resin however runs into a 

 mass in boiling water like turpentine. The water has a 

 bitter taste, and has no action either upon turnsole or upon 

 violet syrup. The resin, on the contrary, reddens turnsole 

 tincture strongly. 



3. Olibanum forms in hot water a thick magma, which 

 is separated with difficulty from the liquor, even by filtra- 

 tion. This water has a blackish brown colour, is not pre- 

 cipitated by the acetate of lead, and does not change the 

 colour of turnsole, but alcohol precipitates it in abundance; 

 which proves that this substance is composed of gum and 

 resin. 



The alcoholic tincture reddens turnsole tincture strongly. 



If we carefully heat in a sand bath the resins which have 

 most action on the colour of turnsole, no acid is sublimed. 



When treated with lime according to Scheele's process, 

 no calcareous benzoates are formed. 



4. Ammoniacal gum resin, myrrh, gum elemi, gal- 



banum, 



