Читать книгу Harper's Outdoor Book for Boys - Joseph H. Adams - Страница 37

An odd wind indicator is shown in Fig. 10, illustrating a ball vane in a basket. It consists of a flat basket, with a rim six inches high, made of wire cloth with square meshes; inside of this a silk or cotton covered ball of wire is placed and blown by the wind from one side to the other of the basket. Of course, the direction the wind is coming from is opposite to that taken by the ball.

The basket should be twenty-four inches in diameter, six inches high, and supported at the top of a pole by wires attached from the upper and lower edge of the outer rim, and leading up and down to the pole, the ends being made fast to staples or screw-eyes.

The ball, which is made of wire hoops and fastened together with fine wires, should be from four to six inches in diameter. It is covered with silk or thin muslin sewed on in the same manner in which a baseball is covered with leather. The framework must be of light spring brass or copper wire, and where the hoops cross it would be well to touch the unions with solder to insure a firm joint and make the ball rigid.

If the ball should blow out of the basket at any time, it may be necessary to lace wires across the outer rim at the top, so as to form a confining net-work.

Above the basket the compass points can be arranged on wood or metal arms, and when complete and mounted this weather-vane will present a most unique appearance.