The Fine Wire is Bent as Near as Possible to the Outline of the Object
The device consists of a rather fine wire bent in the shape of a human profile and supported on a stand or base. The stand may be dispensed with, however, and the wire held in the hand. In use, it is placed near the model or person whose profile is to be drawn; then, after closing one eye, it is set at a position where it will correspond to the features of the model. This enables one to note the variations between the wire and the model's features. For instance, the forehead may recede from the wire at the top, or the nose may have a different slant or shape.
The paper on which the drawing is to be made should have a faint outline drawn by laying the wire upon it and marking around it with a soft pencil. Having noted the variations between the wire and the features, proceed to draw the profile, observing the same variations, and when the sketch is completed, erase the faint outlines. Then compare the drawing with the model without using the wire, and make final corrections. The dotted line indicates the outline to be erased.
The drawing may be made larger or smaller than the bent wire, but the outline on the paper must be kept in exactly the same proportion. It is not necessary that the wire be bent so that it represents perfect features. With the use of this device one forms a habit of comparing and proportioning, which applies to the correct sketching of all objects.—Contributed by Will L. Burner, Columbus, Ohio.
A Small Hydroelectric-Power Plant
Wherever a water pressure of over 30 lb. is available a small hydroelectric-power plant will produce sufficient electric current for any light work, such as charging storage batteries, operating sewing and washing machines, toys, etc. The design is for a 6-in. hydraulic motor of the Pelton type, which will operate well on almost all city-water pressures, and at 80 lb. will drive a 100-watt generator to its full output.
The castings may be procured from any foundry cheaply, so that these parts need not trouble the builder. The patterns can be constructed easily and are not so complicated that they will tear the molds when being removed. They are made from well seasoned white pine, 1/4 in. thick. Fill in all sharp corners with small fillets. All the patterns should taper slightly from the parting line.
Layout for the Casing, Cover and Wheel for the Construction of a Hydraulic Motor That will Drive a Small Dynamo, to Produce Current for Experimental Purposes, to Charge Storage Cells or to Run Electric Toys (Fig. 1)