Fig. 47. PITH-TUMBLER.
Because the lead B is specifically heavier than the pith to which it is attached; it therefore always falls undermost; and as the lead is rounded off, just like the spill of a top, after the head has oscillated a little, and expended the force of the momentum of its fall, it will settle upon its centre of gravity, or the point through which it is attracted to the earth.
869. Why do the figures upon the "Thaumatrope" appear to dance, when they are made to revolve before a mirror?
Because the eye, in looking through the holes in the card, towards the reflections in the mirror, receives a rapid succession of impressions. As the figures upon the card are represented in a graduated series of positions—the first one standing upright, the second with his knees a little bent, the third a little more bent, as in the act of springing, and so on, the figure being in each case the same, but the position slightly altered, imparts an impression to the mind, through the eye, that one figure is passing through a series of motions.
Thaumatrope.—From two Greek words, meaning wonder and to turn.
We have said enough, we hope, to show that even the play-hours of children may be made instructive to them; and that the simplest toys may be used to illustrate some of the grandest laws of nature. Nor may this kind of instruction be confined to children alone. Grown-up people, whether participators in the sports of youth, or simple observers of their games, may gain instruction for themselves, and be the better teachers of their children, by taking an interest in their enjoyments, and giving to their minds, through the attractiveness of pastime, a taste for observing and estimating the varied phenomena which present themselves.
Moreover, we think that parental government acquires a greater power when it leans towards the natural desires of childhood, and wins those desires into a proper direction. Love existing between parent and child is the best tie to home, and the strongest incentive to duty. There is also something in the gentleness of childish nature which may influence for good the sterner mould of man, too often warped and clouded by the cares of life.
Jesus said, Suffer little children, and forbid them not, to come unto me; for of such is the kingdom of heaven."—Matthew xix.