Abstract: Apparatus for the thermal conversion of solids containing hydrocarbons. In one embodiment for solids which can be converted entirely to vapour, pieces of the solids are continually fed into a molten lead bath in an oxygen free atmosphere in an elongated conversion chamber. An auger partially immersed in the lead bath carries the floating pieces along in the molten lead bath until they are gradually converted to hydrocarbon vapour which rises upwardly to a condenser. In another embodiment for solids which can be converted to a vapour, particulate matter and residual solids, the lead bath extends further into a separation chamber with an inclined retaining skirt extending between the conversion chamber and the separation chamber, The auger forces the particulate matter and residual solids remaining after vaporization down under the inclined skirt, but the hydrocarbon vapour is prevented from escaping into the separation chamber.