1 835.] of the Distillation of Pit Coal 49 



detected by dipping a stick of 'fir moistened with muriatic 

 acid in a vessel containing pyrrol, when it is tinged purple 

 red, and which like the effect of cyanol is not removed by 

 chlorine. Paper, &c, treated in the same manner remains 

 colourless. The colouring power of the compounds of pyrrol 

 is not less strong than that of cyanol. Nitric acid produces 

 in the aqueous solution of pyrrol a red colour. 



It is difficult to detect pyrrol in coal oil, as the cyanol and 

 carbolic acid render its re-action indistinct, but it may 

 easily be discovered in water which has been employed to 

 wash common street gas, by saturating it with muriatic 

 acid, and dipping into it a stick of fir. A purple red colour 

 is occasioned. 



Pyrrol forms the principal constituent of empyreumatic 

 ammonia, and when its peculiar smell is known, it may be 

 distinguished among the odours which are disengaged by the 

 distillation of bones and horns. Pyrrol is also contained in 

 tobacco oil. 



3. Leucol. 



Leucol (white oil) has been so termed because its re-action 

 is colourless. It does not produce a blue colour in muriate 

 of lime, nor does it communicate to fir any tinge. Leucol 

 is an oily substance, and is well characterized by the salts 

 which it forms with acids. It loses its smell by its com- 

 bination with acids, and forms with oxalic acid crystallized 

 salt. 



When brought in contact with the moist skin, acetate of 

 Leucol emits a smell like phosphorus. 



Acids. 

 1 . Carbolic Acid. 

 This acid is a colourless oily substance, sinking in water. 

 Its smell is extremely empyreumatic; it is caustic and 

 burning, and has a strong action on the skin. When the 

 skin is rubbed with it a feeling of burning is felt, and a 

 white spot is produced, which on being touched with water 

 becomes red, and in some days desquamates. In this re- 

 spect it corresponds with creosote, but differs in being acid ; in 

 being precipitated by acetate of lead, and in not being altered 

 by ammonia or the atmosphere, and in being converted by 

 nitric acid even diluted into a reddish brown matter. 



VOL. I. E 



