The antiquary now directed the attention of Mrs. Seymour to his English coins. "This," said he, "is a shilling of Henry VII., curious as being the first shilling ever struck: it was presented to me by a college friend some years ago, and I have been lately informed that it is so rare as to fetch twenty-five pounds; but let me beg you to examine attentively this curious little treasure," said the vicar, his eyes twinkling with pleasure as he placed the dainty morsel in the hand of Mrs. Seymour; "it is," continued he, a silver groat of Perkin Warbeck; on one side are the Royal arms, but without a name; they are surmounted, you perceive, with an arched crown, and placed between a fleurde-lis and a rose."

"What is the inscription ?" asked Mrs. Seymour.

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"Say legend, Madam, if you please; the words are Domine, salvum fac regem,' the date 1494. The coin is supposed to have been struck by the order of the Duchess of Burgundy for Perkin Warbeck, when he set out to invade England." "Pray," said Tom, "have you got a Queen Anne's farthing?"

"It is really curious," observed the vicar, "that wellinformed persons should still continue to be deceived with regard to the value of this coin. The absurd notion of its being worth 100l. arose from an advertisement of an old lady, who had lost one, stating it to be one of the only three known in the world, and worth at least 1007. The truth is, I understand from my much-valued friend of Tavistock Street, that these farthings generally fetch from five to twenty shillings each; there are several different types of them, but the only one intended for currency is that bearing the date of 1714; all the others were struck as patterns. This is certainly scarce, in consequence of the death of the Queen taking place before the coinage was finished. The farthing and sixpence of Oliver Cromwell are much more scarce and valuable; the one generally brings 10. the other as much as 251. It appears that, after Oliver had stamped his head upon them, he was afraid to issue them as current coins, which accounts for the few which have been handed down to us."

"You remind me," said Mr. Seymour, " of a story I lately heard of a crown-piece of Oliver selling at a public auction for as much as two hundred guineas-can it be possible ?"

"You labour under a mistake," answered the vicar; "the coin you allude to is known amongst collectors by the name of the Petition crown of Charles the Second, and it is undoubtedly a most inimitable piece of workmanship. The story is this: Simon, the artist, had been employed by Oliver Cromwell, and at the Restoration, in order to obtain the patronage of Charles, executed the crown-piece in question. It resembles in its general appearance the common milled five-shilling piece, but on the edging there are two lines of letters beautifully executed. The words are, Thomas Simon most humbly prays your Majesty to compare this his tryal piece with the Dutch, and if more truly drawn and embossed, more gracefully ordered, and more accurately engraven, to relieve him.''

"And what said Charles to it ?" inquired Mrs. Seymour.

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Charles," said the vicar, "took no notice of him, on account of his having worked for Cromwell, and the poor artist shortly afterwards died of a broken heart."

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"Well," exclaimed Mr. Seymour, "his manes must be surely appeased, if his crowns now sell for two hundred guineas each."

The party, soon after this exhibition, quitted the vicarage, highly gratified, and returned to the Lodge, where, after the usual ceremonies at the toilet, they sat down to dinner, in the enjoyment of which we will now leave them, and put an end to the present chapter.

CHAPTER III.

MOTION ABSOLUTE AND RELATIVE.-FORCE.-UNIFORM, ACCELERATED, AND RETARDED VELOCITY.-THE TIMES OF ASCENT AND DESCENT ARE EQUAL.-VIS INERTIÆ.-FRICTION.-ACTION AND REACTION ARE EQUAL AND IN OPPOSITE DIRECTIONS.-MOMENTUM DEFINED AND EXPLAINED. -THE BATTERING-RAM OF VESPASIAN.-THE THREE GREAT LAWS OF MOTION.

"THE table-cloth is removed," cried Tom, as he cast a sly glance through the open window of the dining-room.

"It is, my boy," replied Mr. Twaddleton; "Diffugere nives, as the poet has it."

"Et redeunt jam gramina campis," added Mr. Seymour, archly, as he pointed to the verdant luxuries spread over the table.

"Et decrescentia flumina prætereunt," continued the vicar, with a smile, as he passed the nearly-exhausted bottle; "but, psha! enough of wine and quotation. Come, let us join the children."

Mr. Twaddleton, accompanied by Mr. and Mrs. Seymour, and Louisa, rose from the table, and proceeded to the lawn.

"The gravitation of Tom's ball," said Mr. Seymour, "furnished an ample subject for our morning's diversion; let us try whether its other motions will not suggest further objects of inquiry.

"I well remember," observed Louisa, "that Mrs. Marcet extols that apple, the fall of which attracted the notice of Sir Isaac Newton,* above all the apples that have ever been sung by the poets: and she declares that the apple presented to Venus by Paris; the golden apples through which Atalanta

The story of the fall of the apple having suggested to Newton the nature of universal gravitation has been questioned. It is, however, an historical fact that an apple-tree formerly stood near his house, and that upon its having been blown down, such was the veneration entertained for its remains, that a chair was constructed out of them.

lost the race; nay, even the apple which William Tell shot from the head of his own son, cannot be brought into comparison with it."

"Well said! Mrs. Marcet," exclaimed Mr. Seymour; 66 upon my word, had the mother of mankind used but half such eloquence in praise of an apple, we cannot wonder at its influence."

"What honours then," continued Louisa, "shall we decree to Tom's ball, if it instructs us in the first principles of philosophy?"

"We are trifling," observed Mr. Seymour; and, so saying, he took the ball from Tom's hand, and rolling it along the ground, exclaimed, "There it goes, performing, as you may perceive, two different kinds of motion at the same time; it turns round, or revolves on its axis; and goes straight forward, or, to speak more philosophically, performs a rectilinear motion."

Tom said that he did not exactly comprehend what was meant by the axis. His father, therefore, informed him that the axis of a revolving body was an imaginary line, which was itself at rest, but about which all its other parts turned, or rotated: "But," continued he, "can you tell me whether you understand what is meant by the word motion?”

"If he can," exclaimed the vicar, "he is a cleverer fellow than the wisest philosopher of antiquity, who, upon being asked the very same question, is said to have walked across the room, and to have replied, 'You see it, but what it is I cannot tell you.""

"Your ancient acquaintances," observed Mr. Seymour, "entertained some very strange notions touching this said subject of motion. If I remember right, Diodorus denied its very existence; but we are told that he did not himself remain unmoved, when he dislocated his shoulder, and the surgeon kept him in torture while he endeavoured to convince him, by his own mode of reasoning, that the bone could not have moved out of its place. We have, however, at present, nothing to do with the ancients; the philosophers of our own times agree in defining motion to be the act of a body changing its situation with regard to any other; and you will

therefore readily perceive that this may actually happen to a body while it remains absolutely at rest."

Well, that beats all the paradoxes I ever heard," cried Tom; "a body, then, may be in motion while it is at rest ?" Certainly," replied Mr. Seymour; "it may be relatively in motion, while it is absolutely at rest."

"How can a body change its place," said Louisa, "except by moving ?"

"Very readily," answered her father; "it may have its relative situation changed with respect to surrounding objects. There is your ball, and here is a stone; has not each of them a particular situation with respect to the other; and by moving one, do I not change the relative situation of both ?"

"I perceive your meaning," said Tom.

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To prevent confusion, therefore, in our ideas, it became necessary to distinguish these two kinds of motion from each other by appropriate terms; and, accordingly, where there has been an actual change of place, in the common meaning of the term, the motion which produced it is termed ABSOLUTE motion; whereas, on the contrary, when the situation has been only relatively changed, by an alteration in the position of surrounding objects, the body not undergoing any change in space, the motion is said to be RELATIVE."

"Surely, papa," said Louisa, no person can ever mistake relative for absolute motion; what then is the use of such frivolous distinctions? When a body really moves, we can observe it in the act of changing its place, and no difficulty can arise about the matter."

"Nothing, my dear, is more fallacious than our vision; the earth appears motionless, and the sun and stars seem as if they revolved round it; but it is scarcely necessary for me to inform you that our globe is constantly moving with considerable velocity, while the sun remains at rest.—Mr. Sadler, the famous aëronaut," continued Mr. Seymour, "informed me that he was never sensible of the motion of the balloon in any of his excursions, but that as he ascended into the air, the earth always appeared as if sinking