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through all the degrees, up to the complicated and combined powers of body and mind, in MAN!

The links are kept up, by the addition of muscles for additional motions; by other senses, for hearing, seeing, &c.; and by various degrees of irritability in those senses.

The blood for renovation circulates through the lungs; and for action through the muscles of the heart; secretions take place by the various glands; the contraction of the muscles move the bones; the nerves convey the effect of the mental secretions to the brain; and there produce the inscrutable powers of sensation, will, and judgment.

498. Although animals, in general, are sufficiently distinct from vegetables, yet the gradations of nature are so minute, that many animals are but slightly removed from vegetables, having not more than one or two senses; and, as in some shell-fish, have not even the power of loco-motion.

Between these and man, there is a regular succession of that cunning and sagacity, which are necessary to preserve and sustain life; yet, between man and most other animals, there is, in mental capacity, as great a difference, as between some of those and vegetables.

Far as creation's ample range extends,

The scale of sensual, mental powers, ascends:
Mark, how it mounts to man's imperial race,
From the green myriads in the peopled grass:
What modes of sight, betwixt each wide extreme,
The mole's dim curtain, and the lynx's beam:
Of smell, the headlong lioness between,
And hound sagacious, on the tainted green:
Of hearing, from the life that fills the flood,
To that which warbles thro' the vernal wood!

The spider's touch, how exquisitely fine!
Feels at each thread, and lives along the line:
In the nice bee, what sense so subtly true!
From poisonous herbs extracting healthy dew:
How instinct varies in the groveling swine,
Compar'd, half-reasoning elephant, with thine!
"Twixt that, and Reason, what a nice barrier!
For ever, separate,-yet, for ever, near!

POPE.

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Obs.-In Art. 127 and 128, were described the transformations of insects, from the egg to the worm; the worm to the chrysalis and the chrysalis to the butterfly. The following cut represents those four states in the common caterpillar :

THE EGGS, CATERPILLAR, CHRYSALIS, AND BUT

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XX. Chemistry.

499. The principal object of chemistry is to ascertain the elementary or first principles, of which bodies are composed.

The ancients conceived that there were but four elements, or first principles;-Air, Water, Earth, and Fire: of these, and by their mutual action, they conceived that every kind of matter was composed.

Modern experimental philosophy has, however, analysed three of these elements, or has discovered other elements of those elements; and until these may have been analysed by further experiments, we must consider them as elementary bodies.

Obs.-SIR HUMPHREY DAVY, in the preliminary observations to his Elements of Chemistry, beautifully observes, that "the forms and appearances of the beings and substances of the external world are almost infinitely various, and they are in a state of continued alteration." The whole surface of the earth even undergoes modifications. Acted on by moisture and air, it affords the food of plants; an immense number of vegetable productions arise from apparently the same materials; these become the substance of animals; one species of animal matter is converted into another; the most perfect and beautiful of the forms of organized life, ultimately decay, and are resolved into inorganic aggregates; and the same elementary substances, differently arranged, are contained in the inert soil; or bloom, and emit fragrance in the flower; or become in animals, the active organs of mind and intelligence. In artificial operations, changes of the same order occur; substances having the characters of earth, are converted into metals; clays and sands are united, so as to become porcelain; earths and alkalies are combined into glass; acrid and corro

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