German princess, he had for many years allowed his affection to be divided by one of his own subjects. That other proved at last as faithless as he himself had done, and along with many bitter remembrances there remained nothing that he could love except a beautiful and engaging child whose father he was. Mademoiselle N was now seventeen, and was affianced to a young officer, with the Emperor's full approval. The splendid trousseau was ordered at Paris. The marriage-day drew near, and everything promised fair. It was a morning in the great square of the capital, and the Emperor was reviewing a detachment of his guards. An aide-de-camp rode up, and requested leave to speak with his imperial highness in private. At once the quick eye of affection divined the fatal message. Mademoiselle N— was gone! A mortal paleness overspread the face of the hapless father, and as he struck his hand on his forehead those near him heard him exclaim, " I receive the punishment of my sins." In a few moments, however, and by a great effort, he summoned composure sufficient to conclude the review, and then rode dejectedly off the ground.

The death of this child and its sudden announcement had on Alexander an effect like Nathan's message on the monarch of Israel; and, whilst receiving the blow as a punishment from God, amidst his remorse for the past he felt reviving for the wife of his youth the tenderness of early affection. "Elizabeth had tears to shed for the daughter of her rival, and none sympathised more deeply than she with the suffering father. He began to see in her what his own people and the people of Europe had long seen, an angel of goodness and resignation; his former affection to her revived, and he sought to cause her to lose the bitter recollections of the past, by his constant, assiduous, delicate, and devoted attention. His respect for her, and his tenderness towards

her, increased daily, and he seemed again to feel attachment for life in her all-powerful fascination.” *

But amidst her past sorrows the health of the Empress had been broken, and in the autumn of 1825 her husband set out to prepare for her a residence in the south, where they might pass the winter together. But in his rapid journey he caught the fever of the Crimea, and expired at Taganrog, December 19. Shortly before he breathed his last, looking up at the Empress who sat beside him night and day, he said, "Never have I felt such a glow of satisfaction as at this moment; I thank you from the bottom of my heart." Soon after the rattle was heard in his throat, and the power of speech was gone. "He made a sign to the Empress to approach, and imprinted a last and fervent kiss on her hand." She continued kneeling by his bed-side, "with her eyes fixed upon him, as he gradually became weaker and weaker, until all signs of life were gone. Then, rising, she closed his eyes, and with a handkerchief bound up his head, to support the lower jaw. After this, she

folded his hands over his breast, kissed his hand, and then knelt down by the side of the dead body for half-an-hour in prayer to God."+ This noble-minded woman was not destined long to survive her husband. She died on her way back to Petersburg on the 16th of the following May.

* Schnitzler, vol. i. pp. 101, 102.

+ Lee's "Last Days of Alexander," p. 48. Alison's "Europe since the Fall of Napoleon," ii. 218.

PAPERS ON THE AIR AND SKY.

No. VI.

RAINBOWS, HALOS, AND THE MIRAGE.

THE unobstructed light as it streams down from the blue sky illuminates all things, clothing them in their rich and varied tints, but shows no colour itself; rendering everything visible, it is itself unseen, save by its effects. Yet the white ray is a cord composed of threads of many hues, and it may be untwisted by what is termed refraction, as may be seen at any time by causing it to traverse a wedge of glass.

Just in this way the sun glancing on the falling shower wakes into being the rainbow. Without presupposing in our readers a good knowledge of optics, it would be impossible adequately to describe the formation of this "bridge betwixt the earth and heaven." Suffice it to say, that the rays of light which strike the upper portion of each round drop of falling water are refracted, and those within a certain angle are reflected, and bring from the lower portion of the drop to the spectator's eye the magic colours of the divided light. This taking place with the whole cluster of drops in those parts which are in a similar position in respect to the sun and the observer, forms a great coloured arch spanning the earth, perhaps against the dark background of a black thunder-cloud. The rays which enter at the lower portions of the drops suffer a similar refraction, and form a second bow with the colours reversed; but, as less light is reflected in this case, the arch is always fainter, and in the majority of instances is not noticed at all. If the

phenomenon be very brilliant, we may distinguish all the rays from the red to the violet; but often, on account of the smaller power of red light, only the yellow and blue are recognisable; and sometimes from their pre-eminent luminosity the yellow rays stand out alone.

Every one has observed that an oar when plunged into the water appears bent upwards. In a similar manner, whenever light passes from a denser into a thinner medium, or vice versâ, the ray is bent, and the object from which it is reflected is seen in an unreal position. Now it frequently happens that through the agency of heat or moisture different layers of air are in different states in respect to density, and this gives rise to strange appearances-coloured halos round the sun, mock suns shining at the same time perhaps as the true one, and brilliant curves or lines of light crossing the sky in varied directions. But the most remarkable of these is the "mirage," that takes place when the air at the surface of the earth is much hotter than that a little above it: then objects appear in their wrong positions; and the thirsty traveller over the sandy plains of the desert sees before him tempting lakes of water that on approaching fade away, leaving nought but the hot still air that created the illusion. This phenomenon may frequently be seen on our own shores on a hot summer's day, when the outline of sea and land becomes indistinct, and promontories or islands seem as though suspended in the air: and something similar may be seen on a small scale over the surface of a field where mown grass is being rapidly converted into hay. In Polar regions, too, an analogous phenomenon often presents itself, icebergs or ships being seen inverted over the horizon, or raised far above the sea.

The deep blue of the sky is supposed also to be owing to the refraction of light; and to the same cause must certainly be referred the various colours which clouds assume.

Had

the earth no atmosphere, the setting of the sun would be instantly followed by profound darkness, but the property which the air possesses of bending a ray and the reflexion from clouds cause not only that the orb of the sun lingers on the horizon longer than it otherwise would do, but that some of his light reaches us long after he has disappeared.

While treating of meteorology it may be expected that something should be said about those masses of metal which sometimes fall from the sky. In all countries and in all ages have well-attested instances of this phenomenon appeared: the many ancient stones "which fell down from Jupiter" might be cited, or the fine collection in our British Museum might be referred to-all consisting of iron together with some nickel and cobalt, with occasionally other elements, but scarcely containing the least quantity of the most extensive and universal of terrestrial substances-oxygen. The subject would be a most interesting one, but though the origin of these aerolites is still wrapt in great mystery, it is almost universally allowed that they are not formed in the air, but come to the earth from some other quarter in the planetary spaces; and were we to trace back their descent we should speedily pass from our field of discussion-the earth's atmosphere.

It was intended to bring this series now to a close, by a description of the electrical phenomena that present themselves in the aerial spaces, but the subject is too large, and must be reserved for a separate paper. J. H. G.