THE RESim. 251 



on account of the water or crystals of abietinic acid 

 contained in them. They find extensive use in the manu- 

 facture of the oil of turpentine and resin, of varnish, 

 sealing-wax, soap, etc. The finer kinds are used in 

 medicine. The common turpentine contains 8-33 per 

 cent, of volatile-oil, much being lost by evaporation in 

 collecting. The thicker it is, the more crystals of abietinic 

 acid ; and, therefore, the less turpentine it contains. The 

 Venetian Turpentine, obtained from the European 

 Larch {Larix Europcea), is dark-colored, but contains no 

 abietinic acid crystals. It has a turpentine odor, but 

 suggestive of nutmeg and lemon. The finest of all tur- 

 pentines is the Canada Balsam, obtained from the 

 Balsam-Fir. It is at first colorless, but becomes yellowish 

 with age, though remaining clear. It has a pleasant odor, 

 and an aromatic and bitter taste. It is nearly as heavy as 

 water, the specific gravity being a little over .99. Starch 

 grains from the potato mounted in it are visible under the 

 microscope, but invisible in other balsams. It is exten- 

 sively used in the preparation of microscopic objects. 



217. The Common Resin, called also Bodn and Colo- 

 phony, is the mass remaining after the natural escape, or 

 the removal by distillation, of the volatile-oil from the 

 turpentines. It consists of resinous acids, together with a 

 very small quantity of the oil of turpentine. Since it is 

 soluble in alkalies it is used in the manufacture of the 

 common kinds of soap. It is also used in the preparation 

 of ointments and plasters, in the manufacture of varnishes, 

 cements, etc., in sizing paper, and in lubricating machinery. 

 Resinous wood, after yielding resin, is then often used in the 

 manufacture of tar, illuminating gas, creosote, parafEne, 

 and aniline. Tar is obtained by distillation from roots. 



