Eighteen inches or so below it was another grating in the outer wall.

This arrangement prevented the prisoners from getting a glimpse of the grounds, as well as the air from rushing in too rawly.

My cell was one of the old ones.

In the new cells there is a slightly different method of ventilation.

Two of the small panes of glass are removed from the window, and a little frame is placed inside, consisting of wood at the sides and fluted glass in the front.
Flush with the window-sill at the bottom, it inclines inward at an angle of twenty degrees, so that there is room at the top for a six-inch flap, which works on hinges, and is elevated or lowered by a chain.