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Amgueddfa Cymru
Photograph captioned 'Gelligroes Mill, near Blackwood. The half-row looks into the housing for the first pair of gear wheels. They are bevel gear wheels, the one which is seen to be vertical being fixed to the end of the waterwheel shaft. This bevel gear revolves with the shaft and its teeth engage with the teeth of the horizontal gear wheel causing it to revolve in its turn and to operate a vertical shaft, which runs upwards into the mill building. This vertical shaft then transmits its power through other gear wheels to the mill machinery itself.' Mounted on card. Made for the exhibition RECORDING WALES 3 in 1970/1971.