Plates developed in an ordinary tray must be removed from the bath occasionally for examination. The film when in a chemical-soaked condition is easily damaged. The tray illustrated herewith was made for the purpose of developing plates without having to take hold of them until the bath had completed its work, the examination being made through the plate and the bottom of the tray.
A pocket is provided for the liquid developer in one end of the tray when it
[Illustration: Developing Tray with Glass Bottom]
is turned up in a vertical position. A tray for developing 5 by 7-in. plates should be made 8 in. square inside. The side pieces with the grooves for the glass are shown in Fig. 1. Two of each of these pieces are made with mitered ends. The short groove shown in the top piece of the illustration is for inserting the plate covering on the pocket end of the tray.
Two blocks, one-half the length of the side pieces, are put in between the glass plates to hold the plate being developed from dropping down when the tray is tipped up in a vertical position. The glass bottom of the tray is 8-1/2 in. square, which allows 1/4 in. on all edges to set in the grooves of the side pieces. The wood pieces should be well soaked in hot paraffin, and the mitered corners well glued and nailed. —Contributed by J.A. Simonis, Fostoria, Ohio.
** Iron Putty [269]
A good filler used as a putty on iron castings may be made as follows: Take, by weight, 3 parts of stiff keg lead, 5 parts of black filler, 2 parts of whiting, 5 parts of pulverized silica and make into a paste with a mixture of one part each of coach japan, rubbing varnish and turpentine.
** Rubber Bands in Kite Balancing Strings [270]
Kite flyers will find it to their advantage to place rubber bands of
[Illustration: Bands in String]
suitable size in the balancing strings to the kite, as shown in the illustration. This will prevent a “break-away” and also make the right pull, if only two bands are put in the lower strings. —Contributed by Thos. DeLoof, Grand Rapids, Michigan.
** An Aid in Sketching [270]
Sketching requires some little training, but with the apparatus here illustrated an inexperienced person can obtain excellent results. The apparatus is made of a box 8 in. deep, 8 in. wide and about 1 ft. long. A double convex lens, G, is fitted in a brass tube which should have a sliding fit in another shorter and larger tube fastened to the end of the box. A mirror, Ii, is set at an angle of 45 deg.
[Illustration: Sketching Aid]
in the opposite end of the box. This reflects the rays of light passing through the lens to the surface K, which may be either of ground or plain glass. The lid or cover EF protects the glass and keeps the strong light out when sketching. The inside of the box and brass tube are painted a dull black.