These two rotating cylinder drums are operated by pulleys. On each drum is a spigot and each has a rectangular pan underneath. The drum on the left is smaller than the one on the right.
At the center of the photograph is a brick structure enclosed by a metal frame on wheels. The man on the left is operating a switch and there are pipes leading from the structure into two oil drums on the right.
This illustration diagrams the destructive distillation of wastes by (Cline) Continuous-Feed Process, Agricultural By-Products Laboratory, Ames, Iowa, September 13, 1934
A researcher is looking into a large drum. There is a wheel on top of the drum which is operated by a pulley. A second researcher is pouring a liquid into another machine. A third researcher with a notebook looks on.