Of the interior mill work the stairs are the most important. For the small house they should be very simple, not only for economy but for appearance. Plain round and square balusters, 1³/₁₆ inch, and two to a tread, simple hand-rail and simple newel post, 3¾ inches, are more effective than elaborately turned members. The height of the hand-rail from the top of the tread to the hand-rail on a line with the face of the riser should be 2 feet 6 inches. The slope of the stairs should preferably be confined between 30 degrees and 35 degrees, and the common proportion between tread and riser should be maintained (tread and riser = 17½ inches). [Illustration] The treads should be of 1⅛-inch hardwood, and the risers of 1³/₁₆-inch softwood, rabbeted into the riser. Outside strings ought to be ⅝ inch thick where finishing on a ⅝-inch base. Inside strings should be 1³/₁₆ inches thick. Enclosed stairs between walls should have strings fitted down on treads and risers, but elsewhere inside strings should be rabbeted for treads and risers. Newels should be housed out over supports. [Illustration: This is what the speculative builder spends money on] A feature of the small house which is neglected too much is the installation of built-in furniture. There is a substantial quality about such furniture which no mobile furniture can possess. The bookcase built into the wall, the window-seat permanently a part of the room, a charming mantel-piece, good panelling, built-in china-closets, tables, and benches in the breakfast alcove, a modern kitchen dresser with the equipment of a portable cabinet, dressing-tables, and closet shelves and drawers, medicine-cases and radiator enclosures are features which add so much to the small house that it seems strange that they are so often omitted. Many a speculative builder has realized the value of such furniture and sold his house upon the attractiveness of it. He knows that the young couple who purchases the small house usually comes from the small apartment, and has little furniture to spare. Here then is a place to spend money and not to economize. XII LESSONS TAUGHT BY DEPRECIATION What happens to the small house after it has been built? This is a question which should interest both the architect and builder, because from the answer can be had some very important lessons in construction. To know where the weather, mechanical wear and tear, fire and water, begin the decay of the house is to know where to specify materials which will give the greatest durability to the whole.