52 F. F. Runge on the Products [Jan. 



to crystallize. Fine needle crystals of oxalate of leucol first 

 appear, and after some time crystals also of oxalate of cyanol 

 make their appearance. The latter are in broad plates of 

 a brownish colour, and change with muriate of lime to a 

 violet blue, and turn wood to a yellow colour. 



Should the two salts after separation not be quite pure, 

 they should be repeatedly dissolved in alcohol and crystal- 

 lized. To separate the two bases from the salts, it is only 

 necessary to distil them with soda ley, when they pass over 

 into the receiver with the vapour of the water. 



Separation of Pyrrol. 



It is extremely difficult to obtain pyrrol in a separate 

 state, in consequence of its affinity for carbolic acid. To 

 obviate the effects of the acid, it is best to saturate the 

 empyreumatic ammonia which passes over from the distilled 

 bones with an acid. The matter which passes into the re- 

 ceiver should be mixed in the first Woulf 's bottle, after be- 

 ing filtered, and the discharged gases absorbed by caustic 

 potash, or lime-water. By distillation, the pyrrol is carried 

 into the receiver, forming a colourless solution, which pro- 

 duces a purple-red in wood. To purify the pyrrol, it should 

 be distilled with muriatic acid, when muriate of pyrrol 

 passes over. When distilled with caustic ley the pyrrol 

 comes over pure. 



' Separation of Carbolic Acid. 



Agitate together 12 parts of coal-oil ; 2 of lime, and 

 5 of water, at intervals, for six or eight hours. The filtered 

 liquid should be boiled down to a fourth part, filtered after 

 cooling, and mixed with an excess of muriatic acid. Im- 

 pure carbolic acid collects at the bottom of the vessel, in 

 the form of a brownish oil. The supernatant liquid should 

 be removed, the brown oil washed with water, and subjected 

 to distillation. A milky liquid passes over, from which 

 some colourless oily drops separate, which are pure carbolic 

 acid. As much water is now to be added to the receiver 

 as will dissolve the oil, and then the liquid precipitated with 

 acetate of lead. Carbolate of lead is formed, which after 

 being well washed, is subjected to dry distillation. The car- 

 bolic acid collects in the receiver in the form of a yellow oil, 



