and resolution of forces may be explained at the same time. The nature of elastic springs will require no other apparatus for its elucidation than Jack-in-the-box, and the numerous leaping-frogs and cats with which the nursery abounds. The leathern sucker will exemplify the nature of cohesion, and the effect of water in filling up those inequalities by which contiguous surfaces are deprived of their attractive power; it will, at the same time, demonstrate the nature of a vacuum, and the influence of atmospheric pressure. The squirt will afford a farther illustration of the same views, and will furnish a practical proof of the weight of the atmosphere in raising a column of water. The theory of the pump will necessarily follow. The great elasticity of air, and the opposite property of water, I shall be able to show by the amusing exhibition of the Bottle Imps.'"

"Bottle Imps!

vicar.

6

6

Acheronta movebis,'" muttered the

Mr. Seymour continued. "The various balancing toys will elucidate the nature of the centre of gravity, point of suspension, and line of direction: the see-saw, rocking-horse, and the operation of walking on stilts, will here come in aid of our explanations. The combined effects of momentum and a change in the centre of gravity of a body may be beautifully exemplified by the action of the Chinese Tumblers. The sling will demonstrate the existence and effect of centrifugal force; the top and tetotum will prove the power of vertiginous motion to support the axis of a body in an upright position. The trundling of the hoop will accomplish the same and other objects. The game of bilboquet, or cup and ball, will show the influence of rotatory motion in steadying the rectilinear path of a spherical body, whence the theory of the rifle-gun may be deduced. For conveying some elementary ideas of the doctrine of oscillation, there is the swing. The flight of the arrow will not only elucidate the principles of projectiles, but will explain the force of the air in producing rotatory motion by its impact on oblique surfaces: the revolution of the shuttlecock may be shown to depend upon the same resolution of forces. Then comes the kite, one of the most instructive and amusing of all the pastimes of youth, the favourite toy of Newton in his boyish days*its ascent at once developes the theory of the

* Sir Isaac Newton is said to have been much attached to philosophical sports when a boy; he was the first to introduce paper kites at Grantham, where he was at school. He took pains to find out their proper propor.

composition and resolution of forces, and explains various subordinate principles, which I shall endeavour to describe when we arrive at the subject. The see-saw will unfold the general principle upon which the Mechanical Powers are founded; and the boy may thus be easily led to the theory of the lever, by being shown how readily he can balance the heavier weight of a man by riding on the longer arm of the plank. The theory of colours may be pointed out to him as he blows his soap-bubbles*; an amusement which will, at the same time, convince him that the air must exert a pressure equally in all directions. For explaining the theory of sound, there are the whistle, the humming-top, the whizgig, the pop-gun, the bull-roarer, and sundry other amusements well-known in the play-ground; but it is not my intention, at present, to enumerate all the toys which may be rendered capable of affording philosophical instruction; I merely wish to convince you that my plan is not quite so chimerical as you were at first inclined to believe."

"Upon my word," said the vicar, "no squirrel ever hopped from branch to branch with more agility,—you are the very counterpart of Cornelius Scriblerus; but I must confess that your scheme is plausible, very plausible, and I shall no longer refuse to attend you in the progress of its execution. Cedo equidem, nec, nate, tibi comes ire recusof,

as Virgil has it."

Mr. Seymour, however, saw very plainly, that although the vicar thus withdrew his opposition, he was nevertheless very far from embarking in the cause with enthusiasm, and that, upon the principle already discussed, he would perform his part rather as a task than a pastime. Nor was the line which Mr. Twaddleton had quoted from the Æneid calculated to efface such an impression. It was true, that, like Anchises, he no longer refused to accompany him in his

tions and figure, and the proper place for fixing the string to them. He made lanterns of paper crimpled, which he used to go to school by in winter mornings with a candle, and he tied them to the tail of his kites in a dark night, which at first frightened the country people exceedingly, who took his candles for comets. Thomson's Hist. of R. S.

The colours which glitter on a soap-bubble are the immediate conse. quence of a principle the most important from the variety of phenomena it explains, and the most beautiful from its simplicity and compendious neatness in the whole science of Optics.-- Herschel's Preliminary Dis

courses.

"I yield, my son, and no longer refuse to become your companion."— En. ii. 704.

expedition; but, if the comparisons were to run parallel, it was evident that he would have to carry him as a dead weight on his shoulders. This difficulty, however, was speedily surmounted by an expedient, with which the reader will become acquainted by the recital of what followed.

"I rejoice greatly," said Mr. Seymour, "that we have at length succeeded in enlisting you into our service; without your able assistance, I fear that my instruction would be extremely imperfect; for you must know, my dear sir, that I am ambitious of making Tom an antiquary as well as a philosopher, and I look to you for a history of the several toys which I shall have occasion to introduce."

This propitiatory sentence had its desired effect.

"Most cheerfully shall I comply with your wishes," exclaimed the delighted vicar; "and I can assure you, sir, that, with regard to several of the more popular toys and pastimes, there is much very curious and interesting lore." Mr. Seymour had this occasion succeeded in opening the heart of the vicar, just as a skilful mechanic would pick a patent lock; who, instead of forcing it by direct violence, seeks to discover the secret spring to which all its various movements are subservient.

upon

exultation, we will commence our career im thê I anticipate the highest satisfaction and acinare: the mean time," continued he, "I will refresh my memory spon contain points touching the antiquities of these suit pas times, of, as we used to say at college, get up the subject. I will also press into our service my friend and neighbour Jeremy Prybabel, whose etymological owiece wil greatly assist us in tracing the origin of many of the words used in our sports, which is frequently not very chrious"

Mi Neymour cast an intelligible glance at his wife, who was no less surprised at the sudden change in the vicar's sentiments than she was pleased with the skill and address by which it had been accomplished.

ON GRAVITATION.

CHAPTER II.

WEIGHT.- THE VELOCITY OF FALLING BODIES. AT WHAT ALTITUDE A BODY WOULD LOSE ITS GRAVITY. THE TOWER OF BABEL. THE KNOWN VELOCITY OF SOUND AFFORDS THE MEANS OF CALCULATING DISTANCES. -AN EXCURSION TO OVERTON WELL. AN EXPERIMENT TO ASCERTAIN ITS DEPTH.-A VISIT TO THE VICARAGE.THE MAGIC GALLERY.- RETURN TO THE LODGE.

It was about two o'clock, when Mr. Twaddleton, in company with Mr. and Mrs. Seymour, joined the children on the lawn.

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

"Quite ready, papa."