English: Cornish boiler, Bancroft Mill A hand fired Cornish boiler by John Thompson of Wolverhampton. Unusual for British practice as the furnace tube is eccentric to improve circulation. Note the two water level gauge glasses, pressure gauge, firehole door and feed check valve on the front. Two springloaded safety valves can be seen on the top. The mill ran on a large Lancashire boiler in the adjoining room. This smaller boiler was to allow the mill to function when the mill engine was not required but in practice it was not used as it it interfered with the draughting of the Lancashire boiler.