Chap. 5,] Refim. 53 



glafs veflfels. Chaptal fays, that the Dutch mix an 

 ounce of .quick-lime wkh every pound of camphor 

 previous to diftillation. 



VJI. RESINS are dried juices of plants, of the na- 

 ture of efiential oils. Almoft all the concrete juices, 

 diftinguifhed by the name .of r-efms, are foluble in ar- 

 dent fpirit, and not in water, whereas gums are 

 foluble in water, and not in fpirit. They ufually flow 

 from wounds made in the trunks of trees purpofely to 

 obtain them. They are inflammable, and burn with 

 much fmoke. In clofed veflels they do not rife 

 wholly by heat, but are decompofed. -ReCns differ 

 from balfams in .their fmell, which is lefs agreeable, 

 and efpecially in their containing no concrete acid fait. 

 The common refin of the pine, the refm of the fir, 

 pitch, tar, and turpentine, re perfect refms, and are 

 foluble in fpirit of wine* Copal, and the elaftic fub- 

 ftance called caoutcbouc 3 which is the infplffated juice 

 of an African tree, are ufually but improperly reckon- 

 ed among refinous fubftances j though neither fpirit 

 of wine nor water diffolves them. They arc foluble, 

 -however, in oils, by the affiftance of heat, and have 

 been thought to be of the nature of -fat oils, though 

 they differ in many remarkable properties. 



The juices called gum-refins, or the mixtures of 

 gum and refin, are not completely foluble either in 

 water or fpirit of wine. Both thefe menftrua, how- 

 ever, by duTolving one of the component parts, 

 fufpend a portion of the other, from their intimate 

 union. 



yill. PURE FECULA OF VEGETABLES. If the fub- 

 ftaoce of a vegetable is reduced to a pulp by pound- 

 ing, this pulp by ftrong preflure affords a turbid 

 E 3 white 



