"Furthermore, there is, in the corner ... a button, which on being turned causes a small gong to be struck in the corridor without, and at the same moment make a metal plate or "index" outside the door start out at right angles to the wall, so that the warder when summoned by the bell, may know which prisoner has rung."

(Criminal Prisons in London and Scenes of Prison Life gan H. Mayhew a J. Binny, cyhoeddwyd gyntaf yn 1862.)

"Dangosydd cell, Carchar Wandsworth."

(Criminal Prisons in London and Scenes of Prison Life by H. Mayhew a J. Binny, cyhoeddwyd gyntaf yn 1862.)