“I see you understand it. Here, then,” continued Mr. Seymour, “is another toy in further illustration of our subject. It consists of a small figure, supported on a stand by a ball, which is quite loose; and yet it is made to turn and balance itself in all directions, always recovering its erect position, when the force applied to it is removed. The two weights, in this case, bring the centre of gravity considerably below the point of suspension or support, and therefore maintain the figure upright, and make it resume its perpendicular position, after it has been inclined to either side; for the centre of gravity cannot place itself as low as possible, without making the figure stand erect.”
“That is very evident,” cried Louisa.
“I shall next exhibit to you,” continued Mr. Seymour, “a toy that furnishes a very good solution of a popular paradox in mechanics; viz. A body having a tendency to fall by its own weight, how to prevent it from falling, by adding to it a weight on the same side on which it tends to fall.”
“That is indeed a paradox!” exclaimed Louisa. “The next time I see the gardener sinking under the load of a heavy sack, I shall desire him to lighten his burden by doubling its weight.”
“Will you, indeed, Miss Pert? I do not think so, after you have seen the operation of the toy I am now about to exhibit. Here, you perceive, is a horse, the centre of gravity of which would be somewhere about the middle of its body; it is, therefore, very evident that, if I were to place its hinder legs on the edge of the table, the line of direction would fall considerably beyond the base, and the horse must be precipitated to the ground; you will, however, perceive that there is a stiff wire attached to a weight which is connected with the body of the horse, and by means of such an addition, the horse prances with perfect security at the edge of the precipice: so that the figure which was incapable of supporting itself is actually prevented from falling, by adding a weight to its unsupported end!”
The children admitted the truth of this statement, and were not immediately prepared to explain it.
“The weight, indeed, appears to be added on that side; but, in reality, it is on the opposite side,” said the vicar.
“In order to produce the desired effect,” observed Mr. Seymour, “the wire must be bent, so as to throw the weight far back, under the table; by which contrivance, since the centre of gravity of the whole compound figure is thrown into the leaden weight, the hind legs of the horse thus become the point of suspension, on which the ball may be made to vibrate with perfect security.”