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may, however, be total eclipses within a small distance of the nodes; but their duration is the less as they are farther from them; till they become only partial ones, and at last none at all. - 4. The moon, even in the middle of an eclipse, has usually a faint appearance of light, resembling tarnished copper; which Gassendus, Ricciolus, and Kepler attribute to the light of the sun, refracted by the earth's atmosphere, and so transmitted thither. Lastly, she grows sensibly more pale and dim before entering into the real shadow, owing to a penumbra which surrounds that shadow to some distance.

In addition to these circumstances, some astronomers observe, that no eclipse of the moon can last above 5 hours, from the moon's first touching the earth's penumbra to its last leaving it: but an eclipse of the moon, by the earth's shadow, perhaps never lasts above 32 hours; nor when total, above 12 hours.

1. What happened on this day, B. C. 720 ? 2. What occasions the eclipse of the moon?

3. At what time do lunar eclipses happen?

4. What are the chief circumstances of lunar eclipses ? 5. What occasions total eclipses ?

LESSON LXXIX.

MARCH THE TWENTIETH.

Sir Isaac Newton.

On this day died the great Sir Isaac Newton. He was born at Woolstrope, near Grantham, in the county of Lincoln, December 25, 1642. He received the early part of his education at Grantham, and completed his studies at Cambridge, where the rapidity of his progress in mathematical knowledge was truly astonishing. He perceived the theorems and problems of Euclid, as it were, by intuition; and at the age of twenty-four, he had laid the foundation of his most important discoveries. He was the first who gave a rational account of the laws which regulate the motion of the planets, on the principles of the attraction of gravitation.

"All intellectual eye, our solar round

First gazing through, he, by the blended power
Of gravitation and projection, saw

The whole in silent harmony revolve."

Newton first discovered the heterogeneous mixture of light, and the production of colours arising from it.

ON LIGHT AND COLOURS.

"Even light itself, which every thing displays,
Shone undiscover'd till his brighter mind
Untwisted all the shining robe of day;

And, from the whitening, undistinguishable blaze,
Collecting every ray into his kind,

Again,

To the charm'd eye educed the gorgeous train
Of parent colours."

"Ye mouldering stones,

That build the towering pyramid, the proud
Triumphant arch, the monument effaced
By ruthless ruin, and whate'er supports
The worship name of hoar antiquity,

Down to the dust! what grandeur can ye boast
While Newton lifts his column to the skies,
Beyond the wastes of time? Let no weak drop
Be shed for him. The virgin in her bloom
Cut off, the joyous youth, and darling child,
These are the tombs that claim the tender tear,
And elegiac song. But Newton calls
For other notes of gratulation high,

That now he wanders through those endless worlds
He here so well descried, and wondering talks,
And hymns their author with his glad compeers."

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THOMSON.

1. What illustrious philosopher expired on this day, in 1727 ?
2. Where did he receive the early part of his education?
3. From what author are the poetical extracts taken ?

LESSON LXXX.

MARCH THE TWENTY-FIRST.

On Light and Colours.

LIGHT, which is an extremely attenuated fluid matter, is constantly transmitted from the sun to the earth; and we know, from the labours of those eminent men who have made philosophical discoveries the study of their lives, that it reaches us in little more than eight minutes, which is a velocity almost equal to 200,000 miles in a second of time. The velocity of light, indeed, will appear truly astonishing, when we consider, that were a cannon ball ejected from the sun, it would be more than thirty years in arriving at this earth, though it travelled throughout with the same swiftness that it acquires when first shot out of a cannon! Milton, alluding to the Divine mandate, at the Creation, "Let there be light, and there was light," thus apostrophises :

Hail, holy Light! offspring of Heaven, first born,
Or of th' Eternal co-eternal beam,

Bright effluence of bright essence increate
Thy fountain who shall tell? Before the sun,
Before the heavens thou wert; and at the voice
Of God, as with a mantle didst invest

The rising world of waters dark and deep.

Light is capable of entering into bodies, and of being afterwards extricated without any alteration. Many instances might be adduced of substances which, after being exposed to the sun's rays, appear luminous in the dark, and emit light for a longer or shorter period. In short, light possesses many singular and striking properties. Sir Isaac Newton described it to be a substance consisting of small particles, constantly separating from luminous bodies, moving in straight lines, and rendering bodies luminous by passing from them and entering the eye.

We may also observe that light is decomposable into seven distinct rays of different colours. Some bodies absorb one coloured ray, others another, while they reflect the rest. This is the cause of colour in bodies. A red body, for instance, reflects the red rays, and absorbs the rest. A white body reflects all the rays and absorbs none; while a black body, on the contrary, absorbs all the rays, and reflects none. Dr. Paley has remarked, "that if light had been made by a common artist, it would have been of one uniform colour; whereas, by its present composition, we have that variety of colours which is of such infinite use to us for the distinguishing of objects; which adds so much to the beauty of the earth, and greatly augments the stock of our innocent pleasures." "Nature's resplendent robe !

Without whose vesting beauty all were wrapt
In unessential gloom."

A ray of solar light passing into a dark room through a hole in the shutter, and falling upon a glass prism placed to receive it, becomes divided into seven different rays, each of which bears its own colour. The oblong image which the refraction of the glass produces, affords seven coloured stripes, distributed in regular order. The first from the upper part is red, the second orange, the third yellow, the fourth grey, the fifth blue, the sixth indigo, and the seventh violet. These stripes pass from one into another, by gradations or shades.

If a glass lens be presented to the seven rays, divided by the prism, they will be united into a single ray, which will exhibit a round image of shining white. Hence all

NAPOLEON AT FONTAINEBLEAU..

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the colours united produce white; but if only five or six of these rays be taken in by the lens, it will produce but a dusky white. Two rays only, reunited by this means, afford a colour that partakes of both. A stream of white or natural light, therefore, is a union of seven kinds of rays, the division of which produces seven principal and immutable colours, and their re-union forms white. The absence of all colour, or the negation of light, is black or darkness.

The foregoing remarks will partly demonstrate the cause of that most beautiful object, the rainbow. The sun shines on the drops of rain as they descend in a shower, and the light which enters those drops is broken or divided into various colours, on the principle of the lens above described; and is afterwards refracted and reflected out of the drops all round (according to the position of the spectator), so as to produce that regular succession of prismatic colours by which the heavenly vault is spanned.

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1. At what rate per second is light said to travel from its source, the

sun?

2. Give me Sir Isaac Newton's description of light.

3. Into how many distinct rays is light decomposable ?

4. What are the seven colours formed by these rays of light?

5. What appearance have the seven prismatic rays when united into a single ray?

6. What beautiful object in nature does this lesson illustrate ?

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HERE it was that Napoleon, the spoiled child of fortune, received the first severe lesson from the fickle goddess who had so long favoured him. Here, impatiently waiting for a resignation, which they knew it must fill his heart with unutterable pangs to make, his ungrateful courtiers counted the moments until they could fly from him; fearing that, like the fall of some mighty oak in the forest, which crushes every smaller tree within its reach, his fall should destroy them. They repressed not the symptoms of their cruel haste from him, before whom for years they had bowed down and worshipped; and his eagle eye, accustomed hitherto to meet only looks of homage and adoration, now fell on recreant countenances, whence ingratitude had chased even habitual hypocrisy.

Caulincourt, the flower of French chivalry, forsook him not, whom fortune had crushed; and in the fearful soli

tude of a palace, that echoed back but the footsteps of departing courtiers, or the sighs of their deserted and ruined chief, he staid to console, when he could no longer serve him.

The fall of Napoleon furnishes a fine subject for a tragedy; but the event is too recent to admit of its being done justice to. What must have been the mental sufferings of this hero of a hundred fights, during his detention in this place! The past, the glorious and brilliant past, must have appeared to him but as a dream; and the present, a reality too fearful in its consequences, and disgusting in its details, to be contemplated without dismay. The treatment he experienced in his reverses must reflect eternal dishonour on those whom he elevated to a height, of which their base ingratitude towards him subsequently proved they never were worthy.

The finest willow trees I ever saw are at Fontainebleau ; they were frequently admired by Napoleon, who, when in exile at St. Helena, selected a peculiarly large one for his favourite place of repose during his walks. His thoughts must have been mournful at such moments, when a prisoner on a rock in the ocean, looking only for deliverance by death, and reminded by the willow of those in the far-off land of his glory, he felt that few, if any, ever more strikingly exemplified in their own persons the mutability of fortune.

1. Where is Fontainebleau situated?

2. Why is Fortune designated as a fickle goddess?

3. What is meant by the term "flower of French chivalry?

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4. What must Napoleon have felt when reminded by the willow of his fallen state?

LESSON LXXXII.

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MARCH THE TWENTY-THIRD.
Kotzebue.

THE assassination of Augustus Von Kotzebue, a German author of considerable celebrity, took place on this day, in the year 1819. He was the son of a counsellor of legation of the Duchy of Weimar. Having become, at the age of twenty, private secretary to General Baur, one of the bestinformed military men in Russia, he gained the good-will of the empress Catherine, for whom he composed some pieces, which were acted at the theatre of the Hermitage. Induced by a romantic attachment, he married a noble Russian lady. He was quickly raised to the situation of president of the civil government at Revel, in Esthonia,

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