Relates to retorts for distilling shale or other purposes. Each retort has a mouthpiece, which projects into a water trough, having a curved bottom, and sides rising up to ridges, from which extend shoots. Attached to links is the reciprocating discharge bar, actuated from a steam engine, etc., which, through worm-wheel gearing and a shaft, imparts an intermittent motion to a pawl which propels a ratchet-wheel, which is prevented from turning backward by a catch, and drives a rotary shaft, the motion being transmitted to a bar through a crank and rod. The bar, in rising, pushes the residue from the retort out of the trough, over the ridges, and down the shoots into the truck, etc. The vertical retort is made in two lengths, at the joint between which is held the flange of the shell, joined to, or cast with, the part of the retort and forming a jacket into which steam or other vapor or gas is introduced by a pipe. The steam, etc., circulates through an external spiral rib of the shell and issues from the bottom of the shale among the shale, etc., being distilled.