The anemometer resembles a miniature windmill and is mounted on top of a building or support where it is fully exposed to the air currents. It differs from the windmill in that the revolving wheel is replaced by a cupped disk, A, Fig. 4, fitted with a sliding metal shaft, B, which is supported on crosspieces, CC, between the main frame pieces DD. The latter pieces carry a vane at the opposite end. The frame pieces are 1/2 in. thick, 2-1/4 in. wide and 36 in. long, and the crosspieces have the same width and thickness and are 4 in. long.
(Fig. 5)
A variable-resistance coil, E, is made as follows and fastened in the main frame. The core of this coil is a piece of wood, 2 in. square and 4 in. long, and wound with No. 18 gauge single-wound cotton-covered german-silver wire. The winding should begin 1/4 in. from one end of the core and finish 1/4 in. from the other, making the length of the coil 3-1/2 in. The ends of the wire are secured by winding them around the heads of brads driven into the core. A small portion of the insulation is removed from the wire on one side of the coil. This may be done with a piece of emery cloth or sandpaper. A sliding spring contact, F, is attached to the sliding shaft B, the end of which is pressed firmly on the bared portion of the wire coil. One end of a coil spring, which is slipped on the shaft between the pieces CC, is attached to the end crosspiece, and the other end is fastened to the sliding shaft so as to keep the shaft and disk out, and the flange H against the second crosspiece, when there is no air current applied to the disk A. The insulation of the standard upon which the anemometer turns is shown in Fig. 5. The standard J is made of a piece of 1/2-in. pipe, suitably and rigidly attached to the building or support, and the upper end, around which the anemometer revolves to keep in the direction of the air currents, is fitted with a plug of wood to insulate the 1/4-in. brass rod K. A bearing and electric-wire connection plate, L, is made of brass, 1/8 in. thick, 2 in. wide and 4 in. long. The bearing and connection plate M are made in a similar manner. The surface of the holes in these plates, bearing against the pipe J and the brass rod K, make the two connections for the wires from the variable-resistance coil E, Fig. 4, located on the main frame, to the wire connections between the two instruments. These wires should be weather-proof, insulated, attached as shown, and running to and connecting the indicator with the anemometer at NN, Fig. 1.
Two or more dry cells must be connected in the line, and when a reading is desired, the button H, Fig. 1, is pushed, which causes the current to flow through the lines and draw the magnet core D in the coil, in proportion to the magnetic force induced by the amount of current passing through the resistance in the coils on E, Fig. 4, from the contact into which the spring F is brought by the wind pressure on the disk A.
How to Make Stick Shellac
It is often desired to use shellac in solid or stick form, and to get it into this shape by melting and molding requires considerable time. A much quicker method is to place the shellac in a shallow box, spread it out in a thin layer and play the flame from a Bunsen burner upon it until the mass is melted and run together. Allow it to stand a few seconds, then, with moistened fingers, fold it over and over and shape it with the fingers. It is possible to make a stick 8 or 10 in. long and 5/8 in. in diameter in about 5 minutes.—Contributed by J. H. Beeber, Rochester, N. Y.
Substitute for a Hose Reel
Not having the room to spare for the ordinary hose reel, I used as a substitute a piece of wire bent into the shape of a letter S and with its aid coiled the hose in a manner to expel the water and leave it in shape for storing.
