Page:Popular Science Monthly Volume 89.djvu/311

 Popular Science Monthly

The Whistling Bicycle Wheel

A MOST interesting toy to teach young people the value of harmonic souncls is a device which any boy can make. Fig. i of the illustration shows a side view and Fig. 2 is a top or plan view. Small rubber-tired wheels 10 ins.

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speed up the wheel so that it rotates rapidh". The harmonic devices are sim-

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��-2 in. across. This cut i in. from the closed end.

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��The various parts employed in the con- struction of the musical wheel are here shown in side and plan views

or more in diameter are purchased at any supply house, and are mounted on ball- bearing spindles ready to be attached to a frame. In this description a wheel 12 ins. in diameter is used.

The frame comprises a base prefera- bly 2 ins. thick, 5 ins. wide, and 33 ins. long. Near one end is a pair of vertical posts secured at their lower ends to this base, and they extend upwardly 33 ins., each being made of % in. material. The upper ends are held in alincment by a cross-piece. A grooved pulley, about 2 ins. in diameter, is fastened to the hub of the wheel at one end, which can be done easily by a pair of bolts. The other grooved pulley, 8 or 10 ins. in diameter (such as is used on sewing- machines) is mounted directly above the small pulley on a round rod, one end of this rod being bent to form a crank. A common sewing-machine belt is placed on these two pulleys.

This arrangement enables the user to

��I)ly tin tubes, eacn '4 01 an m. in diameter, and 4 ins. long. By means of a file a cross-cut is made so that the opening is }, should be ^

A tightly-fitting cork }/^ in. long is placed in the end of the tube, and the other end of the tube is provided with a cork designed to move in and out, but tight enough to prevent leakage of air. To this cork a wire loop is attached so that the cork may be drawn out at will and adjusted at the proper place.

The pitch of each whistle thus made depends on the location of the cork within the tube; the nearer it is to the opening the higher will be the pitch. 1 he smaller the tube the more piercing will be the note, so that any number of these whistles may be attached to the rim, some small and others large, thus giving shrill or somber sounds. Instead of tin, papier-mache, brass, or copper tubes may be used. The different ma- terials give what is called the timber tone-color, or quality to the sounds.

These whistles may be tied to the rim of the wheel at various angles with reference to the rim. This will have the effect of imparting peculiar effects to the tones. — J. S. Zerbe.

���A wide range of musical tones can be produced with this home-made outfit

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