A LESSON OF EXPERIENCE.

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cepts. I will endeavour to convert your accident into a source of instruction by showing you how the principles of natural philosophy may be brought to bear upon the most trivial concerns of life. The butt was full of water. When you attempted to wheel it forward, the water did not at once receive the motion thus communicated to the vessel, and from its inertia, or tendency to remain at rest, rose up in a direction contrary to that in which the vessel moved, and consequently poured over. By this time, however, the mass of fluid had acquired the motion of the cart, when you suddenly stopped it, and the water, in endeavouring to continue its state of motion, from the same cause that it had just before resisted it, rose up on the opposite side, and thus saturated our unlucky Rosa."

Louisa was quite delighted with this simple and satisfactory application of philosophy, and observed that she should not herself mind a thorough soaking if it were afterwards rewarded by a scientific discovery.

If,

"I will give you, then, another illustration of the same law of motion," said Mr. Seymour, "which, instead of explaining an accident, may, perhaps, have the effect of preventing one. while you are sitting quietly on your horse, the animal starts forward, you will be in danger of falling off backward; but if, while you are galloping along, it should stop suddenly, you will inevitably be thrown forward over the head of the animal."

"I clearly perceive," said Louisa, "that such would be my fate under the circumstances you state."

Mr. Seymour now proposed that each of the juvenile party should feel for himself the effects of inertia, by observing the effort which was required to set in motion the garden roller, or to stop it quickly when in motion. It was found, in fact, quite impossible either to start or stop it suddenly, and the result of the trials was to give the children a very distinct idea of what is implied by inertia. After this Mr. Seymour asked the party to adjourn to the library, where he had a new toy ready for them, and one or two experiments to show in further illustration of inertia.

To the library they accordingly proceeded, and there Mr. Seymour brought out the new toy, which in reality was a once common but now forgotten amusement, very fashionable about the end of last century. This toy seems to have been invented in France, where it was called the bandalore, but the English

called it a quiz. To such a degree did the fancy for this toy at one time prevail among people of all ages and ranks, that numbers of persons of both sexes were to be seen playing with the quiz in the streets.

Mr. Goodenough here remarked that the origin of the word quiz was itself not a little curious, if Smart's account of it is the correct one. "He says," continued the vicar, "that Daly, the manager of a Dublin theatre, having laid a wager that he could mike a word of no meaning become in twenty-four hours the talk and puzzle of the city, caused the letters QUIZ to be chalked or placarded on all the walls of Dublin, and with such result that he won the wager."

"That is quite possible," said Mr. Seymour; "and I can bring forward another illustration of the way in which such trifles may take hold of the public mind. What do you think most occupied the minds of the fashionable world in Paris about the year 1811? It was neither the famous comet which was then blazing in the sky, nor the gigantic preparations which were then being made for the fatal march into Russia. The mind of society was not possessed by these things so much as by your pardon, vicar-le diable! I do not mean the dark spirit of evil, or the poetical creation of Milton, or the personage of Meyerbeer's opera, but a toy which was only a slight modification of the bandalore as we have it here. The diable was a sort of double humming-top, made to revolve in a manner not unlike the bandalore, by means of a cord passed round the axis and attached to two sticks held in the hand. But I will show you a print, dated 1812, in which you will see a dandy of the period instructing two ladies in the management of the toy." Here Mr. Seymour took a book from one of the shelves, and showed the print, of which Fig. 42 is a reduced copy. "It is here stated," he continued, "that at the Tuileries, in the public gardens, and in the drawing-rooms, every lady and every child was occupied à faire ronfler le diable-in making the top hum."

The bandalore which Mr. Seymour now exhibited in action consisted of two discs of wood, united to each other by a small axis, to which a piece of string is attached. When this string is wound round the axis, and the bandalore is suffered to run down from the hand, the end of the string being held by a loop on the forefinger, the rotatory motion acquired in its descent winds up the string again; and thus, with a little dexterity on

the part of the operator, it will continue for any length of time to descend from and ascend to the hand. In playing with the bandalore, a certain address is required to prevent the sudden check which the toy would otherwise receive, when it arrives at the end of the string, and which would necessarily so destroy its momentum as to prevent its winding itself up again. It affords a good example of the operation of inertia in the case of rotatory motion. Its action may be compared to that of a wheel, which, running down a hill, acquires sufficient motion to carry it up another. There are several toys which owe their operation to the same principle, of which we may particularize the windmill, whose fliers are pulled round by a string affixed to the axis of the sails.

Mr. Seymour now informed his young pupils that he had an experiment to exhibit, which would further illustrate, in a very pleasing manner, the nature of inertia. He accordingly inverted a wine-glass and placed a shilling on its foot, and having pushed it suddenly along the table, the coin flew off towards the operator, or in a direction opposite to that in which the glass was moving. He then replaced the shilling, and imparted to the glass a less sudden motion, and when it had acquired sufficient velocity, he checked it, and the coin darted forward, leaving the glass behind it. Louisa, upon witnessing this experiment, observed that she felt satisfied of the correctness of her father's statement, when he told her that if the horse suddenly started forward, when she was at rest, she would be thrown off behind, and that if it should suddenly stop on the gallop, she would be precipitated over its head.

In concluding the scientific conversation for that day, Mr. Seymour recommended our young friends to consider well the first law of motion, which he hoped they now, to some extent, understood. He trusted this law would be thought of, not as a form of words to be remembered or repeated, but as a short, complete, and really simple statement of what was actually occurring in every movement of the objects around them; and as a principle which, so to speak, governed the actions of their own bodies, as well as the motions of the orbs of heaven. He believed that if they tried to recognize the unceasing operation of this law in the ordinary cases which were continually presenting themselves in their daily life, they would enter with greater advantage upon the subject of gravitation, to which he intended next to direct their attention.

Tom and Louisa hereupon stated that they already knew something about gravitation, from having looked into Mrs. Marcet's and other books; and Mr. Seymour then said that he would test their knowledge by asking them some questions on that subject, when next their scientific recreations were resumed.

IT

CHAPTER XI.

Then breaking hence, he took his ardent flight
Through the blue infinite; and every star
Which the clear concave of a winter's night

Pours on the eye, or astronomic tube

Far stretching snatches from the dark abyss,
Or such as further in successive skies
To fancy shine alone, at his approach
Blazed into suns; the living centre each
Of an harmonious system; all combined
And ruled unerring by that single power

Which draws the stone projected to the ground.

T was about two o'clock when, a few days afterwards, Mr. Seymour, in company with Mr. Goodenough, joined the children on the lawn, in order to continue the course of scientific illustrations.

"Tom," said his father, "are you prepared to undergo the proposed examination ?"

"Quite ready, papa."