The corners of store windows may be treated by adapting any form of bar to the angle, and where it is of advantage to show no bar at all, the two sheets of glass coming together at an angle may be made to support each other by clamping them together with no dividing bar. Several patented forms of connection may be used for this, as well as for the dividing bars. In setting large lights of plate glass, a backing of rubber or leather should be used in place of the usual back-puttying.
Mail Chutes. For the convenience of the occupants of offices above the first floor of any building, the system of mailing letters by means of a specially constructed chute connected with the mail box at the bottom, should be adopted, and location and preparation made for it during the construction. This system, which is patented, must be installed subject to the approval of the local postmaster, and all the apparatus, when erected and accepted by the Post Office department, passes under the care and control of the Government, by which the locks and bozos are authorized.
The boxes are of various sizes and patterns, and are furnished by the makers of the chutes. The chutes are required to be in remov able sections, exposed to view and easily accessible, and they may be run only in the public hall or corridors of a building. The chute must be made of metal with a plate glass front, clearly marked with the insignia of the department, and when installed becomes technic ally a part of the government mail box below.
The requirements for support of the chutes are a continuous vertical surface 10' inches or more in width, carried from the box below to a point not less than 4 feet 6 inches above the top of the highest floor to be supplied. In front of this vertical run must be set the iron thimbles pro vided by the makers, . inches by 9 inches, the whole absolutely plumb, with no bends or offsets anywhere.
For wooden buildings a flat casing of wood may be used, or marble or other costly material may be substituted wholly or in part. This construction is generally used where the chute runs against a wall, as in Fig. 194. Where the chute runs down beside an elevator grille, or in other places where a solid back would be objectionable, two "square root" angle irons are generally used and turned so as to give an even backing, Fig. 195, the thimble in all cases being the same, and the angle irons being secured to the floor beams or other rigid support.
This preparation may be made a part of the building contract or of the mail chute contract, but will have to be clone to the satisfaction and acceptance of the makers of the chutes and of the local Post Office department.