THE REMEDY.
The foregoing cause of the evil being understood, it is also plain that any arrangement which will render the temperature of the air the same on both sides of the pane will remedy the difficulty. Any other method is obviously imperfect and ineffectual. If the temperature within and without the window is the same the glass cannot sweat or frost.
To obtain an even temperature it is absolutely necessary to box the window. It must be cut off entirely from the other part of the store.
FIG. 1.
The space under modern show windows is used largely for ventilating cellars. Our sketch shows half of this space used for ventilating cellar, and other half as a cold air passage to allow the outside air to pass through the double perforated window floor, thereby keeping the air within the window enclosure approximately the same temperature as the outside, and thereby preventing the sweating and freezing, so annoying to the trimmer.
FIG. 2.
A A, open space between double perforated bottom, to be filled with loose cotton to permit the air to pass, but dense enough to keep back the dust from the street.
The floor of the window should be made of boards, perforated and made to fit in snugly without fastening down, so they can be taken up occasionally to clean out the dust that will accumulate in time.
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.