Great pipework (2)
This shows part of the drawstop action of the Great Organ. Each set of pipes has a separate slider to admit wind so that the pipes can sound when the organist plays the keys. The player selects the stops he or she wishes to use by drawing forward a knob, and the stop action (part of which is shown in the photograph) causes the slider to move into position.
Photograph by SRB Humphreys