space between these two a communication is also frequently opened up between two galleries by a partial shaft called a wins.

The excavations in the mine are mainly effected by means of gunpowder. It is said that the annual cost of the gunpowder consumed in the Cornish mines is £18,000 to £20,000. When the ore is blown off by the powder, it is broken into pieces, and put into a large bucket, which is hauled to the mouth of the principal shaft by means of a machine called a whin. This is a hollow cylinder of wood, or cage, revolving on a perpendicular axis, and worked by a steamengine, or, in a small mine, by horses. As it rotates, the rope encircling it alternately coils and uncoils and raises one bucket to the surface, while the empty one is lowered into the pit.

As soon as the ore is raised to the surface it is spalled, or broken into small fragments. The ore is next pounded in the stamping mill, so as to separate the peroxide from the gangue in which it is embedded. From the stamping mill it is carried to a large vat containing water, where, by an operation called tozing or tossing, it is further cleansed and purified. The water is rapidly stirred with a small shovel by women or children, so as to bring the tin-stuff into a state of suspension. When this ceases, the tin, owing to its greater weight, sinks to the bottom, while the earth and other impurities circle at the top, and can be removed. The deposit in the vat is then smelted in a furnace, supplied either with turf or charcoal, and is poured into moulds to cool, after which it is ready for sale.

PROPERTIES AND USES OF TIN.

Tin, symbolised by the name of the planet Jupiter, in consequence probably of its brilliancy, approaches very nearly in its external appearance to silver, having a silvery, but yellowish-white aspect; which, after slightly tarnishing, remains of a permanent and dull white colour. In consequence of its softness, tin is deficient in elasticity, though if cast and placed in sheets one over another between rollers and hardened thereby, it is found to possess more elasticity than is usually attributed to it.

Tin is malleable—that is, it may be beaten out by hammering. Its malleability is made available in the manufacture of tinfoil, which is about one-thousandth part of an inch in thickness, and used extensively in the silvering of mirrors. Tin is one of the cleanest of metals, and will not rust from damp. It is therefore much used for coating other metals. What are improperly called tin saucepans are made of sheet iron dipped in melted tin, to prevent the iron from rusting. Lead, which is in itself poisonous, when it is mixed with tin forms pewter, of which drinking pots, &c., are made. Preparations of tin are also employed in dyeing and other useful purposes. Mixed with gold, it imparts beautiful crimson and purple colours to glass; with flint glass, it makes enamel. Vessels made of tin-plate are much lighter and more convenient for use than those which are made of wood. Sometimes tin-plate vessels are covered with a kind

of varnish called japan. Children's toys, such as little carriages and horses, are often made of thin tin-plate, painted and varnished. These toys are not only amusing to children, but the making of them finds employment for hundreds of industrious persons.

Our young friends will see that we have disregarded the strictly scientific portion of the subject relating to metals, and have looked only at some of the numerous useful purposes to which they are applied. The information now open to us in connection with the metals is so extensive that we have felt great difficulty in selecting the precise facts that would please and instruct "thoughtful boys." What we have aimed at, and what we hope will be achieved by these papers on the metals, is that our youthful readers may gain such rudiments of a knowledge of them as shall lead them to inquire yet further how the raw mineral product of our earth is transmuted into such heaps of precious and useful metals. For the present we must leave them, intending, however, to notice their use in some of the arts at a future time. In our next we shall commence with the "Precious stones."

FOOTPRINTS OF GOD IN NATURE.
By GEORGE PACKER.

XV. THE CAMEL.

IN the structure and endowments of this remarkable animal we shall see one of the most perfect and beautiful illustrations of the direct adaptation of suitable means to a desirable and beneficent end that the whole field of Nature presents to the human vision. Without the camel vast tracts of the earth would be absolutely impassable, and countries and peoples that are now brought together in a commerce that is of mutual advantage would be practically as far asunder as if they occupied different worlds.

The camel is now seldom or never found in a wild state. In those parts of Asia and Africa where it is common, it is as much domesticated as the horse with ourselves, and performs all the services that the horse can render, and many others peculiar to itself besides. As a beast of burden it has great power of endurance, and most of the larger species carry with ease a thousand or twelve hundred pounds. There is a smaller kind that differs from the ordinary camel, just as the slender but swift racehorse differs from the huge and powerful cart-horse that drags behind it a well-loaded railway dray. This is called the dromedary, and is usually employed for its swiftness. ean carry but a small burden, but it can perform a journey of over six hundred miles in four or five days with ease.

It

The camel is of great value, because it can so easily cross those vast deserts that abound in Africa and Asia. On these deserts the rain never falls, and the drops of the dew are never seen, and vegetation is either totally unknown, or is of a very scanty character. For hundreds of miles it is one vast unchanging sea of burning sand. But the camel has powers by which the deserts may be traversed, and is as plainly made for the purpose of crossing these pathless wastes as the eye was made for seeing. It has natural powers of storage for both food and water of the most surprising kind. The large hunch on its back may present to the eye unused to it an unsightly appearance, but its great practical value more than makes up for any apparent blemish to its beauty. It is a store of fat accumulated by feeding at ease in fruitful pastures, from which the animal draws when on its long and tedious journey. For weeks at a time it has to subsist on "short commons," and the hump ekes out the scanty supply of food, and supplies all the nutriment required. When starting on one of its long journeys this hump is very large and full; at the end it is nearly exhausted, and it is only by rest and abundant food that the animal can recover its proper condition again. But it has the power of storing water as well as food. Its stomach is so constituted as to guard against the perils of drought. Over and above the usual complicated arrangements common to all animals that chew the cud, there is a compartment fitted up with cells capable of holding a provision of water ample enough to last six days or more, and from which the animal draws its daily supplies. The merchantmen have often saved their own lives in the desert, when water has been inaccessible, by killing one of their camels and obtaining the water which they well knew the animal had preserved for a time of need. On account of these peculiar and valuable properties, and from the fact that it is only by its means that merchandise can be transported across the Vast oceans of sand, the camel is poetically called "the ship of the

desert."

Its senses of both sight and smell are peculiarly acute, and are of great advantage to travellers in guiding them to such pools of water as they may occasionally pass near. The existence of water becomes known to the camel while he is still miles distant from it; and as soon as it becomes known off he starts for it as straight as a shot discharged from a gun. The eyes are protected from the glare of the sun and the whirling particles of sand by long eyelashes; and the nostrils by a muscular action, capable of being exerted at will, can be so closed as to make the entrance of the sand in a windstorm impossible.

It has a wonderful prescience by which it knows when those perilous and destructive winds, known as simooms, will blow. These are storms of hot sand, and if caught by them unprepared death is inevitable to both man and beast. But just before they come the camels of a caravan will cry out, and run together, and hide their noses in the earth. The men then instantly fall on their faces, and

with closed eyes and mouth, and nostrils protected by their garments, they wait until the storm is over, and the camels lift up their heads and proceed on their journey.

The legs of the camel are long and slender, and so also is its neck, and all their movements exceedingly free. It is hereby enabled to pluck at such grass or trees as on its journey it comes across. Its chances of this kind are so very few that it takes good care not to lose any of them. The foot is broad, and provided with a soft pad, which is protected by a thick sole from the burning heat of the sand. When the animal bears a heavy load, and it sets its feet on the soft, pliable sand, the sand does not yield any more than the soft snow yields beneath the tread of an Esquimaux when provided with large snow shoes. The woolly hair of the camel is admirably adapted to the conditions of its life. It effectually protects the animal from the solar heat, and at the same time prevents its being injured by the keen frosts that in some parts of the year are experienced during the night.

It is common for caravans to cross the deserts for the conveyance of merchandise and of passengers, composed of as many as three and even four thousand camels. The amount of provision carried for the animals is infinitesimally small. Fed once in twenty-four hours, and then fed only with a small bale of barley and dried dates, they will go cheerfully forward week after week. Of their patience and obedience every traveller speaks in highest praise. They kneel down to receive their burdens, and rise up when they have been loaded with their accustomed freight. The skin is exceedingly thick and strong on their knees and breasts, that they may be well protected when kneeling or reposing. They have power to tell when they are overburdened, and too much good sense to attempt the impossible. Accordingly, if the burden imposed upon them is too heavy they cry until it is removed, and will not, except on great compulsion, make any effort to rise before.

Camels were known to the Egyptians very early, for they gave some to Abram when they treated him with special favour. Job in the time of his greatest prosperity had six thousand camels. They are frequently mentioned in Scripture, and very often as tokens of peace and prosperity; as, for example, in Isaiah, where the land of the Jews, as a signal mark of God's favour, is to be covered with a multitude of camels and of dromedaries. They appear to have been used not only for riding and as beasts of burden, but even for purposes of war. The milk and the flesh are commonly used for food, and from the hair both garments and tent-coverings are made. The raiment of John, we are told, was of camel's hair. So manifold and so great are their uses in the East that it is no wonder that the wealth of the greatest men should for ages have consisted in having a large quantity of them. In the year 1676 the King of Persia had seven thousand of them, but this great wealth excited the cupidity of the Tartars, who by resistless force carried off three thousand for themselves.

Without the ocean, as we have already shown in a past article, this earth would be as barren as the moon. But the sea that separates nation from nation is by man's ingenuity actually turned into a channel of intercourse and bond of union. The sandy deserts, like the rolling waters, have magnificent purposes to answer in the great economy of Nature; their influences on climate and atmosphere are all-powerful. But God does not suffer them to divide the nations of the earth. By the creation of the camel what would otherwise be a barrier, huge and insurmountable, is transformed into a great highway, along which all men may easily pass to and fro. This animal is therefore one of the most useful servants man has; and every reflecting mind sees in its structure and habits, so strikingly adapted to its circumstances and man's necessities, a standing proof of the wisdom and beneficence of the great Creator.

TOM FOSTER, THE ORPHAN.
BY CHARLES LEACH.

CHAPTER VI.-RESCUED.

T was Christmas eve. The time when those who have homes hurry to them. The night when our railway stations are crowded with the thousands of those who leave our towns and cities and rush off to the scenes of earlier days. Who can describe all the feelings which steal over those of us who are fighting the hard battle of life as Christmas comes? Leaving the study, office, or factory, we seize the carpet-bags, cram into them the presents we have purchased, and off we go. Some make for home where wife and children are, and here they bring out the treasures, whilst all the children stand round, each anxiously waiting for his share. The merry laugh goes round and all is joy. Others at this season hurry off to the village home of their childhood. Once a year at least they like to come up to see the old folks, and some of those things which pleased them so in earlier days. There are the village church, the parsonage, and the squire's house, all standing just as we have ever known them. And yonder stands the old cottage with its wicker gate and little garden, only somehow looking a little bit less than we thought they were. Inside the cottage we find the same old arm-chair and the rocking-chair, and the same dear old man and woman whom we call father and mother, sitting in them; but they look far more feeble and old than they used to do. But how we like to see them for all that! Christmas is indeed a happy season to those who have homes and friends. But what about those who are poor, and, like Tom Foster, have neither home nor friends? God help all such!