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animal die. Oxygen forms compounds with nearly all the elementary substances. These compounds are known by the general name of oxides, and are divided into two classes, acids and bases, whose qualities are in many respects opposite to each other. Sometimes a third class is reckoned, including those which do not exhibit acid or basic properties, and are therefore denominated neutrals. An acid and a base have generally a strong tendency to enter into combination, and when they do so, the compound formed by them is called a salt. Both oxides and salts are of very frequent occurrence, and of the highest importance, in the mineral kingdom.

Carbon, besides being found pure (as already stated), and in the form of salts called carbonates, is the main constituent of the various species of COAL-a substance of more value to mankind than either gold or diamonds. Fortunately for the progress of science and civilization, coal is found in enormous quantities, and very widely distributed over the earth. It is almost needless to speak of the blessings of which it is the fertile source. By it our hearths are cheered and enlivened, our food rendered palatable, and the severity of our climate mitigated. We extract from it the gas which lights up our streets, our churches, our public buildings, and our homes. Its use is indispensable in many of the arts; and, in particular, it is the chief agent in the production of steam, the grand wonder-worker of our age.

Silicon, or Silicium, occurs chiefly in the form of an oxide, called silica, which is one of the most abundant substances in nature. Rock crystal consists of silica almost in a state of purity; it is less pure, but still the principal ingredient, in common quartz, agate, calcedony, flint, and several other minerals. It is largely disseminated in those stupendous piles of gneiss and granite, of which our sublimest and most gigantic mountains are composed, and contributes not a little to that hardness which enables them to resist alike the disintegrating influence of frost, and the constant wear of streams, produced by the melting of the snow in which their summits are enveloped. The mobile soil of the desert,

rolling with the wind like the waves of the sea, is mainly composed of silicious matter, reduced to the form of sand; and this sand, when again cemented into a compact form, furnishes to the builder the valuable sandstone, of which whole cities are sometimes built.

All the elements which have been mentioned, and a few others, are non-metallic. The metals are a much more numerous class, some of the more important of which will form the subject of future lessons.

QUESTIONS FOR EXAMINATION.

Of what subjects does natural history treat? What benefits do we derive from the study of it? Why, and how, are the objects of nature classified? What is an organ? Name and distinguish two classes of organized bodies. What are minerals? Name the three great divisions of natural history. How does a mineral differ from an organized body in respect of growth? and of decay? Give examples of fluid minerals. When are bodies said to be amorphous? What is a crystal? Describe some of the most common forms of crystals. Give an example of a crystallized substance. How are crystals produced artificially? What is meant by an elementary substance? How many are at present known? Which of them are found pure in nature? Which is most widely diffused? What is an oxide? an acid? a base? a salt? In what substance is carbon abundant? What is silica? Name substances containing silica. In which is it nearly pure?

LADY LILLICRAFT'S RETINUE.

In the first place, her ládyship has a pampered coachman, with a red fáce, and cheeks that hang down like dèw-laps. He evidently dominèers over her a little with respect to the fat horses; and only drives oùt! when he thinks proper, and when he thinks it will be "good for the cattle."

She has a favourite págel to attend upon her pèrson-a handsome boy of about twelve years of age, but a mischievous vàrlet, very much spóiled, and in a fair way to be a good-for-nothing. He is dressed in green, with a profusion of gold córd and gilt buttons about his clothes. She always has one or twò attendants of the kind, who are replaced by others' as soon as they grow to fourteen years of àge.

She has brought two dogs with her also, out of a number of péts' which she maintains at home. One is a fat spaniel, called

Zephyr. He is fed out of shape and comfort; his eyes are nearly strained cut of his head; he wheezes with córpulency, and cannot walk without great difficulty. The other is a little, òld, grey-muzzled curmudgeon, with an unhappy eye, that kindles like a coal, if you only look at him; his nóse turns up; his mouth is drawn into wrinkles, so as to show his teèth; in shòrt, he has altogether the look of a dog far gone in misanthropy, and totally sick of the world. When he walks, he has his tail curled up so tight, that it seems to lift his feet from the ground; and he seldom makes use of more than three legs at a tíme, keeping the other drawn up as a reserve. This last wretch is called Beauty!

These dogs are full of elegant áilments' unknown to vùlgar dogs, and are petted and nursed by Lady Líllicraft with the tenderest kindness. They are pampered and fed with délicacies by their fellow-mínion, the pàge; but their stomachs are often weak and out of órder, so that they cannot eat; though I have now and then seen the page'give them a mischievous pìnch, or thwack over the head, when his mistress was not by. They have cushions for their express use, on which they die before the fire, and yet are apt to shiver and móan, if there is the least draught of air. When any one enters the room, they make a most tyrannical bárking that is absolutely deafening. They are insolent' to all the other dogs of the establishment. There is a noble stàg-hound, a great favourite of the squire's, who is a privileged visitor to the parlour; but the moment he makes his appearance, these intruders fly át him with furious ràge; and I have admired the sovereign indifference and contémpt! with which he seems to look down upon his puny assàilants. When her ladyship drives out, these dogs are generally carried with her to take the air; and then they look out of each window of the carriage, and bark at all vulgar pedèstrian dogs. These dogs are a continual source of mísery to the household; as they are always in the way, they every now and then get their toes trod on, and then there is a yelping on their part, and a lamentation on the part of their mistress, that fills the room with clamour and confusion.

Lastly, there is her ladyship's waiting-woman, Mrs. Hannah, a prìm, pragmàtical old máid, whose every word and look smacks of vèrjuice. She is the very opposite to her mistress, for the òne hátes, and the other lòves all mankind. How they first came together! I cannot imagine; but they have lived together for many years; and the Ab'igail's temper being tart and encroaching, and her ladyship's easy and yielding, the former has got the complete upper hand, and tyrannizes over the good lády in sècret. Lady Lillicraft now and then complàins of it, in great confidence, to her friends, but hushes up the subject immédiately, if Mrs. Hannah makes her appearance. Indeed, she has been so accustomed to be attended by her, that she thinks she could not do without her; and the one great study of her lífe is, to keep Mrs. Hannah in good húmour! by little presents and kindnesses.

WASHINGTON Irving.

LONDON AND ITS FOOD.

Ir, early on a summer morning, before the smoke of countless fires had narrowed the horizon of the metropolis, a spectator were to ascend to the top of St. Paul's, and take his stand upon the balcony, that with gilded rail flashes like a fringe of fire on the summit of the dome, he would see sleeping beneath his feet the greatest camp of men upon which the sun has ever risen. As far as he could distinguish by the morning light, he would behold stretched before him the mighty map of the metropolis; and could he ascend still higher, he would note the stream of life overflowing the brim of hills which enclose the basin in which it stands.

In the space swept by his vision would lie the congregated habitations of two millions and a half of his species,but how vain are figures to convey an idea of so immense a multitude! If Norway, stretching from the Frozen Ocean

down to the southern extremity of the North Sea, were to summon all its people to one vast conclave, they would number little more than half the souls within the London bills of mortality. Switzerland, in her thousand valleys, could not muster such an army; and even busy Holland, within her mast-thronged harbours, humming citieɛ, and populous plains, could barely overmatch the close-packed millions within sound of the great bell at his feet.

As the spectator gazed upon this extraordinary prospect, the first stir of the awakening city would gradually steal upon his ear. The rumbling of wheels, the clang of hammers, the clear call of the human voice, all deepening by degrees into a confused hum, would proclaim that the mighty city was once more rousing to the labour of the day; and the blue columns of smoke climbing up to heaven would intimate that the morning meal was at hand. At such a moment the thought would naturally arise in his mind,-In what manner is such an assemblage victualled? By what complicated wheels does all the machinery move by which two millions and a half of human beings sit down day by day to their meals as regularly and quietly as though they only formed a snug little party at Lovegrove's on a summer's afternoon? As thus he mused respecting the means by which the supply and demand of so vast a multitude are brought to agree, so that every one is enabled to procure exactly what he wants, at the exact time, without loss to himself or injury to the community, thin lines of steam, sharply marked for the moment, as they advanced one after another from the horizon and converged towards him, would indicate the arrival of the great commissariat trains, stored with produce from all parts of these isles and from the adjacent continent. Could his eye distinguish in addition the fine thread of that far-spreading web which makes London the most sensitive spot on the earth, he would be enabled to take in at a glance the two agents-steam and electricity-which keep the balance true between the wants and the supply of London.

The inability of figures to convey an adequate impression to the mind of the series of units of which the sums are

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