EXPERIMENT WITH THE GYROSCOPE.
(From the Mechanic.)
Fig. 149.
The ordinary gyroscopic action takes place when the lever D is held, the weight F being carried horizontally round the vertical axis, passing through the pivots C C. When the wheel is not spinning, the weight F turns the ring A A into the vertical position, so that the weight pulls downwards in the vertical line passing through the centre of the wheel. The parts carried by the lever D are then accurately balanced by means of the adjustable weight H. The ring A A is next held, in the position shown, by the thread G being hooked on the pivot screw opposite the weight F. If now the ring B is turned round on the pivots C C, the gyroscope or the weight H will preponderate accordingly as the weight F is further from or nearer to the supporting point of the pillar E than the centre of the wheel. Finally, spin the wheel, and throw off the thread G. It will then be found that although the weight F, in being carried round by the gyration, is continually altering its distance from the point of support, the apparatus keeps in balance. The gravitation of the weight F is not, as some think, annihilated or converted into horizontal action, but still tells fully, doing so, however, as though acting at the centre of the wheel. If any of my readers should wish to try this experiment, they must have the apparatus very carefully made; and they must bear in mind that the conditions required for the experiment cannot be maintained for many seconds, as the friction of the pivots and other resistances cause the introduction of forces which, slowly at first, but with increasing rapidity, change the relative positions of the parts.—E. H.
Fig. 150.
THE HIGHFLYER.
In two corks, A and B, insert four wing-feathers from any bird, so as to be slightly inclined, like the sails of a windmill, but in opposite directions to each set. A round shaft is fixed in the cork A, which ends in a sharp point. At the upper part of the cork B is fixed a whalebone bow, having a small pivot-hole in its centre, to receive the point of the shaft. The bow is then to be strung equally on each side to the upper portion of the shaft, and the little machine is completed. Wind up the string by turning the bow, so that the spring of the bow may unwind the corks, with their anterior edges ascending; then place the cork, with the bow attached to it, upon a table, and with a finger pressed on the upper cork, press strongly enough to prevent the string from unwinding, and taking it away suddenly, the instrument will rise to the ceiling.—Dr. Piesse.
