Firth Cleveland M and F Series Pumps. Manual
Firth Cleveland M and F Series Pumps. Operator's Instruction and Maintenance Manual
Firth-Brown Hardometer Hardness Tester
Firth Hardometer by Thos Firth & John Brown Ltd of Sheffield. Although classed by the makers as a catalogue, the publication givesfull details of the machine's design, its dimensions, principles of operation,