One of the best starting points for the preparation is the "creosote" obtained from blast furnaces, which is rich in cresols and contains comparatively little phenols. The proportions used are: Creosote, 30 parts; soft soap, 10 parts; and solution of soda (10 per cent), 30 parts. Boil the ingredients together for an hour, then place aside to settle. The dark fluid is afterwards drained from any oily portion floating upon the top.