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Sound travels with the velocity only of about thirteen miles in a minute; therefore, as time is easily divisible into seconds, the space or distance that sounds in general pass through can be readily marked by a stop-watch; consequently, if three persons situated, one close to a gun, when discharged, another half a mile from it, and the third at one mile distant, they would all see the flash at the same instant, but would hear the report at different times.

A variety of experiments have been made with a view to ascertain the exact rate at which sounds pass through the air, and it is now generally agreed, that sound travels with a velocity equal to 1142 feet in a second of time; so that, if 1142 be multiplied by the number of seconds elapsed between the flash and the report, the product will be the exact distance, in feet, between the observer and the gun whence the flash proceeded.

By this easy rule, we can calculate the distance of a ship that has fired a gun, at sea, by night, either as a signal of distress, or otherwise. Suppose, for instance, you saw the flash of a gun, and between that and the report thirty seconds had elapsed, by observation from a stop-watch, you would have to multiply 1142 by 30, and the product, 34,260, is the distance you are from the ship in feet; which, by the rule of reduction, will be found to be 6 miles nearly.

The distance you are from a thunder-storm can also be estimated by the same easy rule. But, as a stop-watch is an expensive article, possessed only by few, it will be a gratification to our juvenile readers to be informed, that each carries constantly about his person what will answer the same purpose as one of those costly machines.

The pulse of a healthy young person, which may be felt the plainest at the wrist, generally beats seventy-five times in a minute, in which time sound travels thirteen miles; therefore, in round numbers, for every six pulsations a mile may be allowed; or 300 yards for a single pulsation.

Suppose, then, you see a flash of lightning, and between that and the thunder you count thirty pulsations, the distance will be found to be five miles; and this method of calculating it will be sufficiently accurate for all your purposes.

3. What is the velocity of sound per minute?

4. What does each person carry about him that will answer the purpose of a stop-watch in estimating distance?

5. About how many pulsations has a healthy young person in a minute ?

LESSON XCVI.- -APRIL THE SIXTH.

Napoleon in the Zenith of his Power.

THE period of which we are about to speak was the autumn of 1808, just after the faithless aggressions of France and Spain had roused the English government to co-operate with the Spaniards in endeavouring to effect the deliverance of their country.

With a piercing glance Napoleon had observed the efforts of Spain, calculated the power of foreign influence in keeping alive the spirit of resistance; and, assigning a just value to the succours which England could afford, foresaw the danger which might accrue, if he suffered an insurrection of peasants, which had already dishonoured the glory of his arms, to attain the consistency of regular government, to league with powerful nations, and to become disciplined troops. To defeat the raw levies which the Spaniards had hitherto opposed to his soldiers was an easy matter, but it was necessary to crush them to atoms, that a dread of his invincible power might still pervade the world, and the secret influence of his genius remain unabated.

At this period it may be truly said, that Napoleon supported the weight of the world; every movement of his produced a political convulsion; yet so sure, so confident was he, of his intellectual superiority, that he sought but to gain one step, and doubted not to overcome all resistance, and preserve his ascendancy; time was to him victory, if he gained the one, the other followed: hence, sudden and prompt in execution, he made one of those gigantic efforts which have stamped this age with the greatness of antiquity. His armies were scattered over Europe. In Italy, Dalmatia, on the Rhine, the Danube; the Elbe; in Prussia, Denmark, Poland, his legions were to be found; over that vast extent, above five hundred thousand disciplined men maintained the supremacy of France. From those bands he drew the imperial guards, the select soldiers of the warlike nation he governed, the terror of the other continental troops; these, and the veterans of Jena, of Austerlitz, of Friedland, reduced in

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number, but of confirmed hardihood, were marched towards Spain: a host of cavalry, unequalled for enterprise and knowledge of war, were also directed against that devoted land, and a long train of gallant soldiers followed, until two hundred thousand men, accustomed to battle, had penetrated the gloomy fortresses of the Western Pyrenees, while forty thousand of inferior reputation, drawn from the interior of France, from Naples, from Tuscany, and from Piedmont, assembled on the eastern ridges of those gigantic hills. The march of this multitude was incessant, and as the troops passed the capital, Napoleon, neglectful of nothing which could excite their courage and swell their military pride, addressed to them one of his nervous orations. In the tranquillity of peace it may seem inflated, but on the eve of battle it is thus a general should speak.

"Soldiers! after triumphing on the banks of the Vistula and the Danube, with rapid steps you have passed through Germany. This day, without a moment of repose, I command you to traverse France. Soldiers! I have need of you! The hideous presence of the leopard contaminates the peninsula of Spain and Portugal. In terror he must fly before you. Let us bear our triumphal eagles to the pillars of Hercules; there also we have injuries to avenge! Soldiers! you have surpassed the renown of modern armies, but have you yet equalled the glory of those Romans, who, in one and the same campaign, were victorious upon the Rhine and the Euphrates, in Illyria and upon the Tagus? Along peace, a lasting prosperity, shall be the reward of your labours, but a real Frenchman could not, ought not, to rest until the seas are free and open to all. Soldiers! all that you have done, all that you will do, for the happiness of the French people, and for my glory, shall be eternal in my heart."

1. Why is it said (in figurative language) that Napoleon supported the weight of the world?

2. From what sources did Napoleon draw his Imperial Guards? 3. Repeat what you can of Napoleon's address to his soldiers.

LESSON XCVII. -APRIL THE SEVENTH.
Liberty and Slavery.

DISGUISE thyself as thou wilt, still, Slavery! still thou art a bitter draught; and though thousands of all ages have

been made to drink of thee, thou art no less bitter on that account. It is thou, Liberty! thrice sweet and gracious goddess, whom all, in public or in private, worship, whose taste is grateful, and ever will be so, till Nature herself shall change: no tint of words can spot thy snowy mantle, or chymic power turn thy sceptre into iron; with thee to smile upon him as he eats his crust, the swain is happier than his monarch, from whose court thou art exiled. Gracious Heaven! grant me but health, thou great bestower of it, and give me but this fair goddess as my companion; and shower down thy mitres, if it seems good to thy Divine Providence, upon those heads which are aching for them.

Pursuing these ideas, I sat down close by my table, and leaning my head upon my hand, I began to figure to myself the miseries of confinement. I was in a right frame for it, and so I gave full scope to my imagination.

I was going to begin with the millions of my fellowcreatures born to no inheritance but slavery; but finding, however affecting the picture was, that I could not bring it nearer me, and the multitude of sad groups in it did but distract me, I took a single captive, and having first shut him up in his dungeon, I then looked through the twilight of his grated door to take his picture.

I beheld his body half wasted away with long expect ation and confinement, and felt what kind of sickness of the heart it was which arises from hope deferred. Upon looking nearer, I saw him pale and feverish: in thirty years the western breeze had not once fanned his blood,he had seen no sun, no moon, in all that time nor had the voice of friend or kinsman breathed through his lattice. His children! But here my heart began to bleed and I was forced to go on with another part of the portrait.

He was sitting upon the ground upon a little straw, in the farthest corner of his dungeon, which was alternately his chair and bed: a little calendar of small sticks was laid at the head, notched all over with the dismal days and nights he had passed there. He had one of these little sticks in his hands, and with a rusty nail he was etching another day of misery, to add to the heap. As I darkened the little light he had, he lifted up a hopeless eye towards the door, then cast it down, and shook his head, and went on with his work of affliction. I heard his chains upon his legs as he turned his body to lay his little stick upon the bundle, he gave a deep sigh, I

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saw the iron enter into his soul,

I burst into tears.

I could not sustain the picture of confinement which my fancy had drawn.

1. How did the captive appear when looked at through his grated door?

2. How long had he been in confinement?

3. In what way did he employ himself?

4. What is meant by the figurative expression, "I saw the iron enter into his soul?"

LESSON XCVIII.. -APRIL THE EIGHTH.

Petrarch.

On this day, in 1341, it being Easter Sunday, Petrarch was crowned with laurel at Rome in the most pompous and magnificent manner.

The taste for poetry and elegant composition, for which the public mind had been prepared by the writings of Dante, ascended to a pitch of enthusiastic admiration when the works of Petrarch appeared. Literary fame, in those days, must have depended on the opinion of a very few competent judges; for, as printing was not then known, the circulation of a new work, by manuscript copies, must have been very slow, and extremely limited. While enjoying this reputation, however, he received a letter from the Mæcenas of the age, Robert, king of Naples. And this honour was followed by a still greater - the revival in his favour of the ancient custom of crowning eminent poets at Rome. Petrarch appears to have indulged the hope of attaining this honour, and not on slight grounds; for in August, 1340, he unexpectedly received a letter from the Roman senate, inviting him to come and take the laurel in that city; and on the same day he received a similar invitation from Paris.

He accepted the invitation from Rome, but thought it necessary first to repair to the court of King Robert at Naples, in March, 1341, and undergo a public examination as to his learning and talents. Having gone through some preliminaries of rather an ostentatious kind, he went to Rome, where, on Easter Sunday, in the midst of the plaudits of the Roman people, the ceremony was performed in the Capitol by his friend Count de' Anguillara. Twelve patrician youths were arrayed in scarlet; six representatives of the most illustrious families, in green robes, with garlands of flowers, accompanied the proces