one reflection and two refractions. In the drop of the second bow, the ray from the sun enters the drop at a, is refracted to B, reflected to c, again reflected to D, where it suffers another refraction as it passes off to the eye at E.

The clear blue sky which generally succeeds the rainbow is the effect of the blue, indigo, and violet rays of light, which, you remember, are most 'reflexible. These are first reflected from the earth, and then again returned from the atmosphere to the earth in the form of that arch of heavenly blue. To the same property of the atmosphere it is owing that all objects are enlightened uniformly on all sides. A strange alteration would take place in the appearance of things on the globe, if the air should be deprived of this property. Then only that side of objects next to the sun would be visible. We should be for the greater part of the time in darkness.

The ancients could not explain the phenomena of the rainbow; but the priests of antiquity held it in veneration, always preferring the wood on which the rainbow had appeared to rest for their sacrifices, superstitiously supposing that this wood had a perfume peculiarly agreeable to the gods.

'Cascades and fountains, whose waters are in their fall divided into drops, exhibit rainbows to the spectator, if properly situated during the time of the sun's shining; and water blown violently from the mouth of an observer whose back is turned towards the sun, never fails to produce the same phenomenon.

1

This appearance is also seen by moonlight, though seldom vivid enough to render the colours distinguishable; and the artificial rainbow may be produced even by candle-light on the walls; by water 'ejected from a small fountain.

1. Vide Root.

2. The rainbow is never seen near noon, for if the sun be above fifty-four degrees high the fainter bow cannot be seen, and if above forty-two degrees the inner bow is invisible.

L

ITALY.

Roman History--(continued.)

IN the year 385 before Christ, a great calamity befel the city. It was taken by an army of Gauls, inhabitants of the country now called France.

2

You must bear in mind that at this time Rome had become an immense place. It contained many 1magnificent 1 edifices; the most splendid of these was called the Capitol this was not taken by the Gauls.

1

All the bravest of the Romans assembled there, and resolved to defend it to the last. Yet the enemy had nearly got possession of it in the night. But as they were creeping up towards the gate, they awoke a large flock of geese; and their cackling alarmed the 'sentinels.

The Gauls were driven out of Rome, and soon 3 vanquished by Camillus, a brave and patriotic Roman. It is said that not a single man of them got back to Gaul, to tell the fate of his companions.

5

The most formidable enemy of Rome was Carthage. The wars between Rome and Carthage were called Punic wars. The first began in the year 264 B.C., and lasted 23 years. Many battles were fought on land and sea.

A peace was at last concluded between Rome and Carthage. The doors of the temple of Janus at Rome, had not been shut for five hundred years; for they always stood open while the Romans were at war. But now

they were closed; for Rome was at peace with the world.

1. Vide Root. 2. Their code of laws were written on twelve tables, and made by the ambassadors who were sent for that purpose to Greece. 3. 390 B.C. 4. Camillus had previously taken Veii after two years' siege. 5. Pyrrhus, king of Epirus, in Greece, gained two victories over the Romans by means of elephants and superior discipline, but lost the third battle and retired. From him the Romans learned to make their celebrated regular encampments. Italy, and believed by the idolatrous Romans to have become a god and to preside over all new undertakings-hence the first month of the year is called January Marius conquered the Cimbri and Teutones, near the Alps.

quered Mithridates, king of Pontus, in Asia Minor.

6. Janus, first king of

8. Sylla con

In the year 218 before the Christian 1era, another war with Carthage began. This was called the second Punic The Carthaginians were commanded by Hannibal, one of the greatest generals that ever lived.

war.

A battle was fought between him and Scipio at Zama. But a third war between Rome and Carthage broke out in about fifty years. This third Punic war ended in the destruction of Carthage. The city was set on fire, and continued to burn during seventeen days. Many of the citizens threw themselves into the flames, and perished. This happened in the year 137 before the Christian era.

The Romans still continued to make conquests. Not long after the ruin of Carthage, the whole of Spain became a province of Rome. There was likewise a war with Numidia, a country of Africa, now called Algiers. Jugurtha, the Numidian king, was brought to Rome, and starved to death in a dungeon.

There was afterwards a social war, beginning in the year 91 B.C. This war was called 'social, because it was between the Romans and the neighbouring states of Italy, who had been their own friends and allies. Three hundred thousand men were killed on both sides. Then there was a war with Mithridates, the powerful king of Pontus, in Asia Minor. He was not entirely vanquished till forty years afterwards. In the course of all this fighting, two Roman commanders acquired great renown. One was named Marius, and the other Sylla. These two generals became so great and powerful, that each was envious of the other. They therefore began a civil war, in which Romans fought against Romans.

8

GEOGRAPHICAL.-Write the names of the principal places on the five rivers-Po, Tiber, Arno, Var, and Adige.

Draw the lines of latitude and longitude which cross Italy, and mark on them the situation of each island.

CHRONOLOGICAL.-Battle of Cannæ gained by Hannibal over the Romans, 232 B C. Scipio Africanus destroyed Carthage, 162 B.C.

Servile war under Spartacus, 89 B.C.

ATMOSPHERIC PHENOMENA.

Morning, or Refraction and Reflection.

THE gradual advance of the day is the consequence of the refractive and reflective power of the atmosphere. The beams of the sun, as soon as they enter the upper part of the atmosphere, are refracted, or bent towards the earth. The density of the atmosphere constantly increases as its nearness to the earth increases. The rays of light in passing through it, are continually passing from a rarer into a denser medium, and are therefore more and more refracted the nearer they approach the earth. In consequence of this refraction, the light reaches the earth long before the direct rays of the sun fall upon it, that is, long before the sun is above the horizon. This is the explanation of twilight. But those rays which are most refrangible will reach the earth first. Accordingly you first see a faint streak of purple light just glancing over the top of the hill, and giving the first signal of the coming day. It is soon blended with a soft tinge of blue. Other rays successively arrive, and add their tints of green, yellow, orange, and red, until they are mingled in pure and perfect light.

These gradations and successions of light cannot always be observed. The atmosphere is frequently filled with a variety of vapours, and the weaker or more refrangible rays cannot get through them, and of course do not reach the earth. This is the reason why the dawn is later in a cloudy than in a clear morning. Sometimes, when the vapours are very dense, only the strongest rays, as the yellow and red, are able to penetrate them.

This is the reason why the sun, in our climate, so often appears to be red in the morning and evening.

It is calculated that the effect of refraction is to make

the sun visible while it is within eighteen degrees below the horizon, as seen in the following diagram, in which

To the inhabitants of the frozen 1 zones the refractive properties of the atmosphere are a blessing of which we, who live in more favoured regions of the earth, can hardly estimate the value: indeed, nearly all the pleasures of their existence depend upon it. In those zones the sun does not rise for a considerable part of the year, and of course is not seen, but the refractive power of the atmosphere preserves a long and mild "twilight during a considerable part of the time when the sun is absent. By means of this the two poles enjoy the light of the sun for nearly nine months of the year.

The aurora borealis, or northern lights, is another atmospheric phenomenon which contributes essentially to the comfort of the polar inhabitants, and relieves the gloom of their long night. Various explanations have been given of this magnificent phenomenon; but none of them are satisfactory.

Persons standing upon one of the heights of the Alps, with the sun behind them, have seen, on an opposite mountain, at a considerable distance, a shadow in the human form, of immense height and gigantic proportions. As this was first seen on the mountain called the 3 Brocken, it is called the Spectre of the Brocken. It is only the reflection of the person's own image, enlarged and 1 magnified by the distance to which the shadow is cast.

3

1. Vide Root. 2. Twilight exists so long as the sun is within eighteen degrees of the sensible horizon, which is that line where the earth and sky seem to ineet. 3. Brocken, the highest of the Hartz mountains, in Hanover, 3000 feet high.