ness; and how appropriate is the exhortation of the apostle 'Wherefore, beloved, seeing that ye look for such things, be diligent, that ye may be found of Him in peace, without spot and blameless."*

TWELFTH WEEK-WEDNESDAY.

VI. HOAR-FROST.-FOLIATIONS ON WINDOW-GLASS.

THERE are some beautiful appearances which frost frequently assumes, to cheer us, as it were, and give an agreeable exercise to our taste, in the absence of that loveliness which the hand of an indulgent Creator sheds so profusely over our fields and gardens, in the genial months of spring and summer. I have already noticed the fantastic forms. which ice assumes at a waterfall, and the pleasure which arises in the mind, on contemplating the loaded woods, and the undulating surface of the earth, after a fall of snow. Nature is almost always either grand or elegant; and, when it is otherwise, the very contrast is a source of enjoyment. In other words, the mind is so constituted as to derive pleasure from all the aspects of the external world. But there are some things better adapted than others to afford gratification to the taste; and, when I mention hoar-frost, a thousand agreeable recollections will arise in every mind. This appearance is occasioned by the freezing of the mist or dew,† and seems to be the result of a process similar to that by

* 2 Peter, chap. iii.

+ The phenomena of dew, and of hoar-frost, when it arises from dew, are owing to the radiation of caloric from the surface of the earth, without any interchange from the sky. The caloric radiated during the night,' says Mrs. Somerville, 'by substances on the surface of the earth, into a clear expanse of sky, is lost, and no return is made from the blue vault, so that their temperature sinks below that of the air, whence they abstract a part of that caloric which holds the atmospheric humidity in solution, and a deposition of dew takes place. If the radiation be great, the dew is frozen, and becomes hoar-frost, which is the ice of dew.'

which snow is formed in the higher regions of the atmosphere. There is this difference, however, that the snow is formed from the rain-drops or humid clouds suspended in the air, without any solid nucleus to which they can adhere ; while the hoar-frost is usually elaborated on the blades of grass, or branches of trees, or other substances with which the moist particles come in contact. It is a well-known law that water does not readily freeze, unless it have some solid substance on which it can form. It is on this account that in a pond or lake, we always see the first appearance of ice either along its margin, or shooting out in long beautiful feathers from some random stick or stone projecting on its smooth surface. In obedience to the same law, the watery particles floating in the air, after being exhaled from the surface of the earth, although they are at, or even below, the freezing point, retain their fluid state when the frost is not very intense, till they meet with something solid, when they instantly become crystallized, and are deposited on the trees, the hedges, and the spreading meadows, in those elegant forms which so far excel the frost-work of art. This happens

frequently in an atmosphere entirely clear; and indeed a cloudless sky is essential to that rapid evaporation from the earth's surface, which gives rise to an abundant dew; but we often observe the hoar-frost also produced by a dense haze, which broods over the surface of the low grounds, during the night, in the form of a sluggish cloud, and which is dissipated by the first rays of the rising sun. In this latter case, the snowy incrustation is thicker and more general, and the effect is like enchantment. The scene which, at nightfall on the preceding evening, was bleak and cheerless, is all at once converted into fairy land. Every vegetable substance, from the blades of grass which lay drooping in the naked fields, to the polished leaves of the evergreen and gnarled branches of the lofty forest oak, is suddenly fringed or clothed with a garniture of purest down, whose beauty surasses the poet's dream, and is scarcely less substantial or less

Another most beautiful effect of frost, which, however, is only rarely observed in this climate, where the alternation from comparative warmth to intense cold is not so sudden as in some other countries, is finely described in the following well known passage of a poetical letter from Copenhagen, by Mr. Phillips :

'Ere yet the clouds let fall the treasured snow,
Or winds began through hazy skies to blow,
At evening, a keen eastern breeze arose,
And the descending rain, unsullied froze.
Soon as the silent shades of night withdrew,
The ruddy morn disclosed at once to view
The face of Nature in a rich disguise,
And brightened every object to my eyes:
For every shrub, and every blade of grass,
And every pointed thorn, seemed wrought in glass;
In pearls and rubies rich the hawthorns show,
While through the ice the crimson berries glow;
The thick-sprung reeds, which watery marshes yield,
Seem polished lances in a hostile field.

The stag, in limpid currents, with surprise,
Sees crystal branches on his forehead rise.

The spreading oak, the beech, and towering pine,
Glazed over, in the freezing ether shine.

The frighted birds the rattling branches shun,
That wave and glitter in the distant sun.
When, if a sudden gust of wind arise,
The brittle forest into atoms flies;

The cracking wood beneath the tempest bends,
And in a spangled flower the prospect ends.'

Nor must I omit to mention yet another pleasing produc tion of frost, in the elegant and varied foliations which are formed on the glass of windows. This appearance takes place most remarkably in cases where the air within the room happens to have been much impregnated with moisture, either from the human breath, when several individuals have been collected, or from any other cause. The coldness of the glass causes the floating vapour to be condensed on its surface, where it shoots out, as it freezes, into those flowery crystals which excite our admiration. The precise cause of

this phenomenon may be obscure, like every other phenomenon of congelation; but the effect is at once curious and pleasing; while, if we trace it up to that law, of which it is only an example, it will acquire a higher importance, and be found to be connected with a principle of vast magnitude in the world of unorganized matter; for the crystallizing process (and freezing is nothing else), seems to form the link between unorganic and organic substances; by the regular structure of its productions, mysteriously uniting crude matter with the vegetable and animal creations.

The pious Sturm, in speaking of this phenomenon, views it in a light different, indeed, but not less important, while his reflection equally applies to the other appearances of frost, which we have been examining. 'Can an object be considered as little,' says he, 'when it furnishes matter for useful reflection? For my own part, I do not disdain to read, even on the frozen glass, a truth which may have a great influence on my happiness. Behold the flowers which the frost has portrayed on the glass. They are beautifully and artificially varied; nevertheless, one ray of the noonday sun effaces them. Thus the imagination paints every thing beautiful to us; but every thing which it represents as attractive in the possession of the goods of this world, is but a beautiful image which shall disappear in the light of reason. The importance of this lesson of wisdom was worth the trouble of stopping for a while, at the little phenomenon which furnishes it.'

TWELFTH WEEK-THURSDAY.

VII. FROST.-BENEFICENT CONTRIVANCES RELATIVE TO SNOW.

As the influence of cold is felt in the air, as well as on the surface of the earth, and indeed becomes more intense, in proportion to the elevation, it must affect the moisture which floats in the atmosphere. The rain-drops must freeze, and,

when frozen, must be precipitated to the ground. Now, were this process to take place in the same manner as it occurs on the face of a lake or pond, and were the water in the clouds to be converted into solid lumps of ice, the most unhappy consequences would ensue, as may be inferred from the damage occasioned by a fall of large hail-stones-an occurrence which sometimes, but rarely, happens, as if to call our attention to the beneficent provision by which this calamity is usually obviated. The fruits of the earth would be destroyed; or, if the season of fruits was past, at least the branches and embryo buds of plants and trees would be shattered; birds on the wing, or on the perch, would be struck to the ground, stunned and dying; the more tender quadrupeds would receive their death-blow; and even the hardy races of animals, and man himself, would not escape material injury. None of these consequences, however, actually take place, because the frozen rain-drops descend, not in the form of ice, or even usually in the less destructive form of hail, but on the downy wings of virgin snow.

Let us consider, then, the properties of snow, and we shall not fail to admire the wisdom of the provision. The vapour floating in the atmosphere is arrested by the cold, and is frozen; but instead of running together, as might be expected, into solid masses, it unites with the nitrous particles, also to be found mingled with the air, and, forming a compound crystal, shoots out into beautiful feathery flakes. Whoever will take the trouble to examine one of these flakes with the aid of a microscope, cannot fail to admire the elegance and skill of its structure. He will observe many He will observe many little sparkling crosses or darts radiating from a point, and branching off and meeting in all directions, so as to form hexagonal lines of much beauty, wrought, apparently, with the nicest art, and wonderfully fitted for passing, with a buoyant and flickering motion, through the air, so as to drop, without disturbance, on the ground, spreading a coat of dazzling whiteness, profusely, but gently, over bush and brake, lawn and mountain. It has been found by experiment, that 'snow is twenty-four