Double thick glass, either French or American, is more durable, and costs less, proportionately, than glass of single thickness.

In main rooms, at least, the custom now is to make the glass large, one pane to a sash, and two to a window; all cost considered, it is about as cheap as to put in several panes of smaller and thinner glass, and it is far better in appearance. If the doors are to have cut glass panels, and it does not add greatly to the cost to have them, each pane must be bedded against putty, that is, putty is first put in around the shoulder against which it rests, and the glass pressed down against it and secured with glazier points, and then fastened with putty; window-glass should be bedded in the same manner.