Products of the Distillation of Pit Coal. 
251 
at least under the circumstances in which other organic co- 
lours disappear. Thus, a piece of Turkey red cotton speedi- 
ly loses its colour, when after being moistened with oxalic 
or tartaric acid it is immersed in a solution of muriate of 
lime. Paper, cotton, linen, wool, and silk are not coloured 
yellow. The effect of the salts of cyanol in colouring pine 
wood is so strong, that a drop containing only of cyanol 
produces a distinct yellow colour in the wood. The yellow 
colouring is not imparted to the fibrous part of the wood, but 
to a peculiar matter in the wood which also exists in other 
species of trees. The resin has no connexion with this co- 
louring power. 
The oil of pit coal contains a great quantity of cyanol, 
whose presence is easily detected by mixing one part of oil 
with a solution of twenty water and one part muriate of 
lime. The oil becomes dark red and the solution assumes a 
blue colour, similar in intensity and appearance to the moist 
ammonia sulphate of copper. It is changed by the muriate 
of lime into an acid which forms compounds possessing a 
blue colour. 
Cyanol is very readily detected by muriatic acid, when 
coal oil is mixed with the latter in the proportion of three 
volumes to one. The acid becomes brown; and a splinter of 
fir wood introduced into the solution, has the yellow colour 
already described communicated to it, thereby indicating the 
presence of cyanol. 
2. Pyrrol. 
Pyrrol (red oil) in a pure state is a gaseous body possess- 
ing the odour of turnips, (markochen ruben) and may be de- 
tected 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 chlo- 
rine. Paper, &c, treated in the same manner remains co- 
lourless. 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 reaction indistinct, but it may easily 
