Abstract: A poking system for use in checking the condition of and agitating the contents of a coal gasifier utilizes a carriage (22) for transporting a poker (50) around the gasifier from one poke hole (12) to another. The carriage (22) mounts a poker assembly (24) comprising a tiltable arm (30) controlled by hydraulic ram (36) and the poker is incrementally inserted into and with withdrawn from each pokehole (12) by means of a reciprocable slide (38) provide with poker engaging clamps (60) which are operated during the advance or return stroke of the slide (38) depending on whether the poker is to be inserted or withdrawn. A pyrometer (72) is provided on the arm (30) for detecting, during withdrawal, the location of that portion of the poker (50) which has been resident within the oxidation zone of the gasifier.