Obs. Of all the arts and professions which at any time attract notice, none appear more astonishing and marvellous, than that of navigation, in the state in which it exists at present. This cannot be made more evident, than by taking a retrospective view of the small craft to which navigation owes its origin; and comparing them to a majestic first-rate ship of war, containing 1000 men, with their provisions, drink, furniture, apparel, and other necessaries for many months, besides 100 pieces of heavy ordnance, and bearing all this vast apparatus, safely to the most distant shores. A man in health consumes, in the space of twenty-four hours, about eight pounds of victuals and drink: consequently, 8,000lb. of provisions are required daily, in such a ship. Let us then suppose her to be fitted out for three months, and we shall find, that she must be laden with 720,000lb. of provisions. A large forty-two-pounder weighs about 6,100lb., if made of brass, and about 5,500lb., of iron; and generally, there are twenty-eight or thirty of these, on board a ship of 100 guns; the weight of which, exclusive of that of their carriages, amounts to 183,000lb. On the second deck, thirty twenty-four-pounders; each of which weighs about 5,100lb., and therefore altogether, 153,000lb.; and the weight of the twenty-six or twentyeight twelve-pounders on the lower deck, amounts to about 75,400lb.; that of the fourteen six-pounders on the upper deck, to about 26,000lb.; and beside that, on the round-tops, there are even three-pounders and swivels. If to this we add, that the complete charge of a forty-two-pounder weighs about 64lbs., and that at least upwards of 100 charges are required for each gun, we shall find this to amount nearly to the same weight as the guns themselves. In addition also, to this, we must reflect, that every ship must have, by way of providing against exigencies, at least another set of sails, cables, cordage, and tacklings, which altogether amount to a considerable weight: the stores, likewise, consisting of planks, pitch, and tow; the chests belonging to the officers and sailors; the surgeon's stores, and various other articles requisite on a long voyage; with the small-arms,

bayonets, swords, and pistols, make no inconsiderable load; to which we must finally add, the weight of the crew; so that one of these large ships carries, at least, 2,162 tons burden, or 4,324,000lb.; and, at the same 'time, is steered and governed with as much ease as the smallest boat.

226. There does not exist a more prodigious and wonderful combination of human industry, than is visible on board a first-rate man of war. It appears incredible that a vessel as large as the largest parish church, should he moved and directed in the water with nearly the same rapidity and precision as a small boat; and it is wonderful that human hands could have fabricated and put together such gigantic materials.

227. The immense ropes and cables consist of hemp spun together; the aggregation of timbers lately grew separately in the forests; the ironwork was melted and prepared from the ore: the cannon were cast in the foundery; in short, the whole fabric has been assembled together by man from the raw productions of the earth!

XII. Geography and Astronomy.

228. Geography describes the surface of the earth; the shape and size of the land and seas; the boundaries of empires and states, and their climate and natural productions.

It also teaches the character of the inhabitants; their government, religion, manufactures, and mode of living; and it ought to enable us to avoid their errors, and profit by their experience.

Obs. As there are numerous works adapted for schools on this subject, and the details are very extensive and prolix; it would be trifling with the pages of this work, to dwell tediously on geography.

229. The earth, on which we live, is a round ball or globe, about 8,000 miles in diameter, and 25,000 iniles round. Its surface is covered with one part of land, and three parts of water, which are inhabited and filled with innumerable living

creatures.

230. Of the internal parts of this immense globe little is known to us. From the surface to the centre is 4,000 miles, yet no mine is a mile deep.

As far as man has penetrated, he has found successive layers or coats of different earths; ly.... ing over each other, like the coats of an onion, or the leaves of a book.

Obs. In digging wells, various thicknesses of different soils are found in different places; and what is remarkable, every layer is nearly the same thickness as far as it extends, and generally parallel with the surface of the earth.-See my Grammar of Philosophy.

231. The highest mountains subtract no more from the roundness of the earth than the inequalities on the rind of an orange subtract from its general rotundity. Chimboraço, one of the Andes, rears its lofty head four miles high, yet this is but the two thousandth part of the earth's diameter.

Obs. The Peak of Teneriffe is but two miles and a half high; and Mount Etna and Mount Blanc not two miles. Our Snowdon is not three quarters of a mile; and but a grain of sand compared to the whole earth.

232. The mines, valleys, and mountains, therefore, may be compared to the inequalities in the rind of an orange; yet, vast as is the earth, the

sun, which lights and warms it, is one million times greater; or, in other words, one million earths united in one mass, would only be the size of the sun.

233. The land consists of two continents; the old one consisting of Europe, Asia, and Africa; and the other, the newly discovered continent of America.

There are also many thousand islands surrounded by the sea; many of them, as Great Britain, anciently united to the continent, and others, the tops of mountains peeping out of the sea, the bases of which are at the bottom of the ocean.

234. When a point of land juts out into the sea, it is called a Cape or Promontory; as the Cape of Good Hope.

When two masses of land are joined together by a narrow slip, it is called an Isthmus; as the Isthmus of Sues, and the Isthmus of Panama.

A Peninsula is the smaller portion of the two; as the peninsula of Spain, in regard to Europe.

235. The waters are usually divided into four Oceans: the Great Ocean, ten thousand miles across; the Atlantic Ocean, three thousand miles across; the Indian and Southern Ocean; and the Northern Ocean.

Seas are detached pieces of water; as the Mediterranean and the Baltic.

Gulfs and Bays are parts of the sea that indent into the land.

And Straits are narrow passes joining one sea: or ocean to another.

236. The vast SUN, to which we are under such sensible obligations, for light, heat, and ve

getation; and without whose genial influence all the Earth would become a dark, solid mass of ice, is 900,000 miles in diameter; and the earth is 95 millions of miles distant from it.

237. The Sun is the centre of a vast system of planets, or globes like the earth; all of which move round his body at immense distances, in periods which include the various seasons to each, and are therefore a year to each.

Obs. They are all pressed to each other's centre; but the action of their fluid parts against their solid parts, gives them a tendency to go forward in a straight line; and those two forces so balance each other, that they neutralize one another, and, in consequence, the planets are moved round the sun in an orbit which is nearly circular. See 267.

238. The Sun has been commonly considered a globe of pure fire. But this has been doubted by modern astronomers, particularly the celebrated Herschel, by whom that great planet is considered an inhabitable globe somewhat like our own; and that its luminous properties which affect our globe, are derived from its atmosphere. A number of maculæ, or dark spots, by means of a telescope, may, however, be seen on his surface, but without any regular periodical returns.

These consist of a nucleus, which is much darker than the rest, and surrounded by a mist or smoke; and they are so changeable as frequently to vary during the time of observation.

Some of the largest of them exceed the bulk of the whole earth, and are often seen for three months together.

They are supposed to be cavities in the body of the sun; the nucleus being the bottom of the

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