Scientific Intelligence. 175 



traces of morbific symptoms remained. The experiment has been 

 tried on various other animals, with similar results. — Idem. 



14. Copal Varnish, by J. J. BerzeUus. — Copal reduced to 

 coi.rse powder, and watered with caustic liquid Ammonia, swells, 

 and is converted into a gelatinous mass, which is entirely soluble in 

 alcohol. To effect this solution, which makes a very beautiful var- 

 nish, liquid ammonia is to be added by degrees, to pulverized copal 

 till the swelling ceases, and it becomes a clear and consistent mass. 

 It is then heated to 35° cent., and introduced in small portions at a 

 time, to alcohol of 8, having a temperature of about 5° cent., shaking 

 it well after each addition. A solution is thus obtained, which, after 

 depositing an insignificant portion of sediment, is absolutely color- 

 less, and as clear as water. — Jour, de Con. Usuelles, Oct. 1828. 



15. On the Oily and Resinous products of the distillation of 

 Wood, by M. BerzeUus. (An. de Pog. 1828, p. 76.) — It is well 

 known that tlie distillation of wood furnishes four distinct products ; 

 1st. An empyreuraatic oil; 2d. An aqueous liquid; 3d. Various 

 gases ; and 4th. Charcoal. 



By repeatedly distilling the empyreumatic oil with water, a por- 

 tion of limpid oil is separated from it, which I call pyreldide, and a 

 resin, which I shall designate by the name of pyretine. 



The pyrelaide varies with the vegetable substance from which it is 

 obtained ; it is colorless, or slightly yellow, of a very strong and 

 disagreeable odor, and a sharp and nauseous taste ; it burns with a 

 clear flame and smoke ; it dissolves more or less easily in alcohol, 

 and very readily in ether, as well as in the fixed and volatile oils ; it 

 fo;.!T!s with concentrated sulphuric acid, a compound analogous to 

 sulphovinic acid ; it dissolves resins and caoutchouc ; nitric acid con- 

 verts it into resin ; it sometimes preserves its fluidity in the air, and 

 sometimes is transformed into a dark resin. 



The pyretine is of a very variable composition. Some varieties 

 contain free acetic acid, and others none.' A substance analagous 

 to idmine, may be extracted from it. 



The aqueous liquid contains, 1, water, 2. acetic acid, rarely ace- 

 tate of ammonia, 3, empyreumatic oil, and some pyretine acid, 4^ 

 an azotized substance, similar to extract, 5, a liquid volatile sub- 

 stance, analogous to alcohol, and known under the name of pyrolig- 

 neous acid. When the aqueous liquid i=: s"' J-^cted to a redistillatioH 



