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he had done before) without power to desist, though perfectly aware of the ludicrous nature of the exhibi. tion he was making: he had a violent inclination to leap over the chair and tables, and felt himself so light, that he thought he was going to fly. Persons who inhale this gas, in place of feeling the debility consequent upon imbibing other intoxicating substances, generally describe themselves as more cheerful and light-spirited during the whole of the day.

COMPONENT PARTS OF WATER.

WATER, as well as air, has only of late years been known as a compound body. For this discovery we are indebted to the labours of Cavendish and Watt, who showed that it is composed of two gases, HYDROGEN and OXYGEN. In order to form water, these ingredients are combined in the proportion of about 2 volumes of hydrogen gas to l of oxygen, or 1 weight of hydrogen to 74 of oxygen. We have had occasion to notice oxygen in treating of the component parts of the atmosphere: we shall now consider the leading qualities of hydrogen gas.--HYDROGEN gas is invisible, and has no taste. When quite pure it has no smell, but, when humid, emits a slight odour. It is the lightest substance which has ever been weighed, being, when pure, upwards of a dozen of times lighter than the atmosphere. Hence air-balloons used always to be filled with it: but of late one of its compounds, called carbureted hydrogen (the same which is now employed in lighting our streets), has been used for this purpose, because it can now be so easily had at the gas-works. It was this compound, which Green made use of, when he ascended from Leith. Hydrogen neither supports respiration nor combustion, so that, if an animal or a burning candle be immersed in it, the former soon dies, and the latter is extinguished. You will hardly, however, expect to learn, that this substance, which forms by far the larger ingredient of water, is itself, by means of oxygen, so highly inflammable, as to have been originally known by the name of inflammable air. It kindles when an ignited body is applied to it in contact with the air; when mixed with twice its bulk of atmospheric air, it explodes when kindled; and, if mixed with pure oxygen gas in the same proportion, the explosion is still more violent. Hydrogen is often collected in mines, forming what is called firedamp, and, by its awful explosion, proves destructive to the miners.-WATER, which is the result of the combination of the two gases above mentioned, is a non-elastic fluid, colourless, tasteless, and inodorous. It is seldom to be found entirely pure and free from mixture. The purest which is to be had, is rain or snow water. Its combinations with other substances are very numerous ; but only in a small proportion of them does it act with much energy, so as materially to alter the qualities of the bodies with which it combines. By the fluidity, however, which it imparts to solid bodies, it acts a most important and indispensable part in most chemical actions. It was long imagined that water was the only compound of oxygen and hydrogen. A few years ago, however, a philosopher of the name of Thenard discovered a new and singular combination of these substances, which is frequently known by the name of oxygenated water. This substance contains twice as much oxygen as water does. It is a transparent and colourless liquid, having little smell, and a strong metallic taste. When pure,

it is of the specific gravity 1453, that of water being accounted 1000. When applied to the skin, it corrodes and discolours it, producing at the same time a sharp prick. ling pain. When dropt upon a combination of oxygen and silver, called oxide of silver, or upon oxide of lead, every drop produces an immediate explosion. It has a strong bleaching power. The different effects, produced by this substance and by water afford a very striking illustration of the different nature of the compounds, which may be produced by the same substances, when combined in different proportions.

ON THE AGENCY OF WATER AS CONNECTED WITH

HEAT.

Let us attend a little to the

powers

and qualities, by which water acts its part, in this system of beings. We all admire its pure transparency in a spring ; the level and polished surface, with which it reflects objects, that are on the banks of a lake; the mobility with which it runs along the channel of a brook, and the incessant motion of its waves in a stormy sea. But, when viewed with a philosophical eye, it appears much more an object of admiration. The same water, which, under its usual form, is such a principal beauty in the scene of Nature, is employed in her most extensive operations, and is necessary to the formation of all her productions. It penetrates the interior parts of the earth, and appears to assist in the production of various minerals, stones, and earths, found there, by bringing their different ingredients together, and applying them to one another properly, that they may concrete. We know that it arises in vapours from the surface of the ocean, to form the clouds, and to descend again in rain upon the dry land, and give origin to springs, rivers, and lakes ; or, upon proper occasions, to form deep snow, which protects the ground and vegetables from the intense and mortal cold, to which some parts of the world are exposed : and, after it has performed this useful office, it readily yields to the heat of summer, and returns to a state, in which it serves the same purposes as rain. By its fluidity and tenuity it penetrates the soil, and the seeds of plants which that soil contains. These it causes to swell and germinate into plants, which depend on water for support. It passes, with freedom and ease, through all their minutest tubes and vessels, and carries with it materials necessary for nourishment and growth, or changes its appearance so as to become part of the plant. There is no plant or vegetable substance, that does not contain, in its composition, a large quantity of water, easily separable from it. The hardest woods contain a great deal. The

sófter and more succulent parts of vegetables are al most totally composed of it. Even the oils and resinous substances can be resolved in part into water. It is plainly as necessary to the animals, and is found to be as copious an ingredient in the composition of their bodies, and of all the different parts of them. These are the numerous and extensive uses of this beautiful substance. But in this succession of forms and operations, which it undergoes, you will perceive that it is set in motion and adapted to these ends, by the nice adjustment and gentle vicissitudes of heat and cold, which attend the returns of day and night, and summer and winter; and that even the form, under which it plays its part, depends on the action of heat. Were our heat to be diminished, and to continue diminished, to a degree not very far below the ordinary temperature, the water would lose its fluidity, and assume the form of a solid hard body, totally unfit for the numerous purposes which it serves at present. And, if the dimi. nution of heat were to go still farther, the air itself would lose its elasticity, and would be frozen to a solid useless matter, like the water; and thus all nature would become a lifeless, silent, and dismal ruin. Such being the important part allotted to water, in the magnificent series of natural operations, in consequence of the qualities communicated to it by heat, all its properties become interesting objects of contemplation to a sensible heart. That peculiarity by which the expansion and contraction of water by heat is distinguished from the same effect on other substances (I mean its irre: gularity between 32° and 40° of Fahrenheit), naturally attracts attention. Even this seemingly trifling distinction has been shown, by Count Rumford, to have a mighty effect in rendering our habitations more comfortable. On the other hand, were the heat, which at present cherishes and enlivens this globe, allowed to increase beyond the bounds at present prescribed to it, besides the destruction of all animal and vegetable life, which would be the immediate and inevitable consequence, the water would lose its present form, and assume that of an elastic vapour like air; the solid parts of the globe would be melted and confounded

&

together, or mixed with the air and water in smoke and vapour; and nature would return to the original chaos.

Black.

DIVISION OF LABOUR. OBSERVE the accommodation of the most common artificer or day-labourer, in a civilized and thriving country, and you will perceive, that the number of people, of whose industry a part, though but a small part, has been employed in procuring him this accommodation, exceeds all computation. The woollen coat, for example, which covers the day-labourer, as coarse and rough as it may appear, is the produce of the joint labour of a great multitude of workmen. The shepherd, the sorter of the wool, the wool-comber or carder, the dyer, the scribbler, the spinner, the weaver, the fuller, the dresser, with many others, must all join their different arts, in order to complete even this homely production. How

many merchants and carriers, besides, must have been employed in transporting the materials from some of those workmen to others, who often live in a very distant part of the country! How much commerce and navigation in particular, how many ship-builders, sailors, sail-makers, rope-makers, must have been employed, in order to bring together the different drugs made use of by the dier, which often come from the remotest corners of the world! What a variety of labour, too, is necessary, in order to produce the tools of the meanest of those workmen! To say nothing of such complicated machines, as the ship of the sailor, the mill of the fuller, or even the loom of the weaver, let us consider only what a variety of labour is requisite in order to form that very simple machine, the shears, with which the shepherd clips the wool. The miner, the builder of the furnace for smelting the ore, the feller of the timber, the burner of the charcoal to be made use of in the smelting-house, the brick-maker, the bricklayer, the workmen who attend the furnace, the millwright, the forger, the smith, must, all of them, join their different arts in order to produce them. Were we to ex

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