FIG. 3.
Fig. 3 shows how boards may be used without being perforated. Small pieces of wood are nailed on one edge of each board, say about one-eighth inch thick, so as to keep the boards about that distance apart.
C is a small door that opens into the store room to reach the cold air space, for cleaning occasionally.
B, opening for lighting and ventilating the cellar. A trap door may be arranged to fit over the opening B, but a better arrangement is to have two sashes of glass to fit the front of the openings immediately back of the wire screens shown in Fig. 2. If hinged at the top, they can be opened by pulling back with a cord or chain from the inside of the room.
Fig. 2 shows a wire screen now much used instead of the more expensive iron grille work formerly in vogue.
When possible, a glass roof should be used to inclose the window, in which case the lights may be arranged above the glass. This prevents heating the window. In using floor drapings, employ only cheesecloth, or some light material that will allow air to pass through.
All this may seem to require considerable trouble and alteration of your windows, but wherever this method has been used it has been found thoroughly practical and an absolute prevention of frost.
OTHER METHODS.
(1) An electric fan kept constantly in motion in a corner of the window is said to avoid frosting by keeping the atmosphere in circulation, and thus preventing condensation upon the surface of the glass. In a large window there should be two fans, in opposite corners, and these may be easily concealed from view.
(2) Electric Heaters.—As almost every store is now provided with electric light service, and electric heaters can be purchased in all sizes on the open market, the interest in this new application of electric heating is universal. All that is necessary is to place a small electric heater in the window in any concealed position, and to connect it with the lighting mains.