Leper's squint, low-side window, or offertory-window, an aperture set low in the south side of a chancel-wall of a church near its west end, or sometimes on both sides of the chancel, or even occasionally in an aisle-wall. Lychnoscopes are found in a great variety of shape and form, but there is no evidence that any were ever glazed. Instead, they were shuttered from within and often protected by an iron grille without. The cill of the opening on the inside was sometimes adapted as a seat (e.g. at Elsfield, Oxon.). They very often commanded a view of a chantry-altar. Various explanations have been given as to the use of a lychnoscope: hearing confessions and giving Communion to lepers or other persons not permitted for whatever reason to enter the church; distributing alms; for sounding a bell during the Manifestation of the Host; and even for ventilation.