432 COMPOUND PRODUCTS. CHAP. I. 



table principles, and is of great utility both in 

 medicine and the arts. Its soft and unctuous 

 qualities render it fit for being employed as an in- 

 gredient in ointments and plasters, and in a great 

 variety of pharmaceutic preparations. It is em- 

 ployed also by the sculptor, statuary, and modeller, 

 in the exercise of their arts. But its chief utility 

 consists in its being better adapted than all other sub- 

 stances for the manufacture of candles. The candle 

 burns with a clear and brilliant flame, and the wick 

 needs no snuffing. 



SECTION XV. 



Resins. 



RESINS are substances somewhat resembling 

 gum, at least in their external appearance, and often 

 exuding spontaneously from the plant that contains 

 them. They are exemplified in the common resin 

 of the shops, and are considered as holding the 

 same relation to volatile oils as wax holds to fixed 

 oils. They are volatile oils rendered concrete by 

 means of the absorption of oxygene, or rather per- 

 haps by the abstraction of part of their hydrogene. 

 Properties. Resins are either soft and viscous, or solid and 

 brittle. They have a slight degree of transparency, 

 and their colour is generally yellowish. Their taste 

 is somewhat acrid, but they are without smell when 

 pure. Their specific gravity varies from 1*0180 to 

 1"228(.). They are non-conductors of electricity, 



