The Dancing Egg.
Place the egg (which should be hard-boiled, not raw) upon the under-side of a smooth tray, and move the tray round and round horizontally, gradually increasing in speed. The egg, resting in the middle of the tray, is carried round and round by the movement, and gradually begins to revolve on its own axis, faster and faster, till at last it is seen to rise on end, and spin away exactly as a top would do.
In all experiments involving egg-balancing, you will find it a material aid to success to keep the egg upright in the saucepan while it is being boiled. The air-chamber will, in such case, be kept central with the longer axis of the egg, which will in consequence be much more easily balanced.
To set the egg spinning as above described demands a considerable amount of practice, not to mention some strength, and, still more, address. For the benefit of those who may prefer to succeed at the first attempt, I will indicate a simpler plan of proceeding:—
Place the tray on the table, letting it project so far over the edge as to be readily and rapidly grasped by the hand. Place the egg in the middle, and with the thumb of the left and the first finger of the right hand placed at opposite ends, set it vigorously spinning. It will immediately rise on end, still spinning. Quickly seize the tray, and you will then have nothing to do but to keep the egg still rotating, which is a very easy matter. This is done by moving the tray in horizontal circles, but in the reverse direction to that in which the egg revolves.