Jean Eugene D'Arcet, of Paris, has invented a new process for the distillation and rectifying of tars, resins, turpentines, bitumens, and mineral oils, so that the process may be (like that of alcohol) continuous. In a vessel divided into compartments, the substances are subjected to a gradually increasing temperature, so that the most volatile constituents are first dissipated, and so on in the inverse ratio of their volatility. Each compartment is provided with a still, and each separate product is condensed as it comes over.