Page:Popular Science Monthly Volume 41.djvu/256

244  (a) Great diminution of dust, since the ashes fall into a closed ash-chamber. (b) Better warming of the room, with a diminution of about one fourth in the quantity of coal used. (c) Diminished draft across the floor, from diminished roar up the chimney when the fire is burning briskly. (d) Diminished production of soot.

These are the principles which I have urged, and they are open to every one to adopt. I do not speak of a further improvement, as it is the subject of a patent, and is not open to every one to copy.

Having made sure of my fire, the next step would be to secure admission of air to supply the fire, without making a draft or introducing dirt. As far as I know this is best done by the "Harding diffuser," which admits air directly from the outside and delivers it through a series of small jets near the ceiling. To shut out the smuts the air passes through a canvas screen placed diagonally in a flat tube, which leads up to the "diffuser" and gives a filtering area about six times the sectional area of the tube. This air is admitted into the room by a legitimate channel, and is filtered. The "Harding diffuser" was once patented, but the patent has lapsed.

Having thus secured a supply of air for the chimney, we can afford to deal with the windows, and make them air-tight, without fear of the chimney smoking. Now I should like to see a revolution in windows, at any rate, wherever we can be content with panes of moderate size, and can have the heart to surrender plate glass.

Three things are required of a good window:

 1. That the outside of the window may be cleaned by a servant standing inside the room, whereby the risk and expense of cleaning from without are avoided. 2. That it shall exclude wind and dirt, even under the stress of a gale. 3. That the air of the room, especially in frosty weather, shall not be itself so chilled by contact with the large surface of glass as to cause induced cold currents, which have not even the merit of being air freshly introduced.

To attain these points, the sash window must be abandoned. The window must be so divided that one half vertically, or in a large window one third, may open inward on hinges, the other half or two thirds being fixed, and therefore wind-tight; the breadth of each division to be such that a servant's arm can reach out and clean the outer side of the fixed window as she stands inside the room. In the case of three divisions the fixed windows would be to the right and left of the hinged window. The hinged