two contacts connects them both.  Nine wires run from the timer, one from each of the eight contacts, and one, which serves as the ground wire, is fastened to the metallic body.  The timer is set at such a position that when the vane points directly north, the brush of the timer makes a connection in the middle of a contact.  When the timer is held in this position the brush will make connections with each of the contacts as the vane revolves.

The indicating device which is placed in a convenient place in the house consists of

[Illustration:  The Wind Vane, Magnets and Indicator]

eight 4-ohm magnets fastened upon a l-in. board.  These magnets are placed in a 10-in. circle, 45 deg. apart and with their faces pointing toward the center.  Covering these is a thin, wood board upon which is fastened a neatly drawn dial resembling a mariner’s compass card.  This is placed over the magnets in such a manner that there will be a magnet under each of the eight principal points marked on the dial.  Over this dial is a magnetic needle or pointer, 6 in. long, perfectly balanced on the end of a standard and above all is placed a cover having a glass top.  The eight wires from the timer contacts connect with the outside wires of the eight magnets separately and the inside wires from the magnets connect with the metal brace which holds the magnets in place.  A wire is then connected from the metal brace to a push button, two or three cells of dry battery and to the ground wire in connection with the timer The wires are connected in such a manner that when the vane is pointing in a certain direction the battery will be connected in series with the coil under that part of the dial representing the direction in which the vane is pointing, thus magnetizing the core of the magnet which attracts the opposite pole of the needle toward the face of the magnet and indicating the way the wind is blowing.  The pointer end of the needle is painted black.

If the vane points in such a direction that the timer brush connects two contacts, two magnets will be magnetized and the needle will point midway between the two lines represented on the dial, thus giving 16 different directions.  Around the pointer end of the needle is wound a fine copper wire, one end of which extends down to about 1/32 in. of the dial.  This wire holds the needle in place when the pointer end is directly over the magnet attracting it; the magnet causing the needle to “dip” will bring the wire in contact with the paper dial.  Without this attachment, the needle would swing a few seconds before coming to a standstill.

The vane itself is easily constructed as can be seen in the illustration.  It should be about 6 ft. long to give the best results.  The magnets used can be purchased from any electrical store in pairs which are called “instrument magnets.”  Any automobile garage can supply the timer and an old valueless bicycle frame is not hard to find.  The cover is easily made from a picture frame with four small boards arranged to take the place of the picture as shown.