That nothing analogous to bitumen exists in coals is proved by the fact that the ordinary solvents for bituminous substances, such as bisulphide of carbon and benzol, have no effect upon them, as would be the case if they contained bitumen soluble in these re-agents.
Though his writings abound in universal solvents and other devices of the alchemists, he made some real contributions to chemical knowledge.
They behave similarly to solvents; and in their liquid condition leave a grease spot on paper.
The process of extraction with volatile solvents is similar to that used in the extraction of oils and fats, but as only the most highly purified solvents can be used, this process has not yet gained commercial importance.
It crystallizes in colourless plates melting at 20°C. and boiling at 202°C.; it is insoluble in water, but readily dissolves in the ordinary organic solvents.