social and civilized life. To this important purpose, among others, the products of the vegetable world, both in a fossil and recent state, are destined; and in examining the origin and general history of some of these products, particularly with reference to common coal, we shall meet with an interesting example of those provisions of nature which Dr. Paley has denominated prospective contrivances.

In the early periods of civilization, and while the population of a country bears a small proportion to the extent of soil occupied, the indigenous forests easily supply an ample quantity of fuel: or, in the absence of those larger species of the vegetable kingdom which may be described under the term of timber, the humblest productions of the morass, though not the most desirable, are however a sufficient substitute. Thus the sphagnum palustre and other mosses, by their successive growth and decay, form the combustible substratum of those extensive and at present uncultivated tracts in Ireland, which, till they shall have happily been reclaimed by the industry of a yet barbarous population, contribute by the turf and peat which they afford, to the comfort of myriads of individuals; who, were it not for this source of supply, would be, in their present state, in total want of one of the principal necessaries of life.

In many populous districts of this island, the aboriginal forests, which formerly so amply supplied the surrounding inhabitants, have long since been cleared from the surface of the earth: and their site is now occupied by cultivated lands and a condensed population. The former source of fuel has consequently in such parts long since failed: but the clearing of the surface has in many places detected that invaluable mineral combustible, which, usually bearing in itself indubitable marks of a vegetable origin, from the traces of organization still apparent in almost every part of its substance, was deposited ages before it was wanted, as a future substitute for the fuel which in the mean time has been derived from the actually existing vegetable kingdom.

It is not intended here to enter into the general consideration of those geological formations called coal fields, which are the repositories of this useful mineral: but there is one circumstance in their history so evidently calculated to facilitate the labour of man in obtaining this substance, and to extend its supply, and so remarkably though not exclusively characteristic of those particular formations, that, though not obvious to a general observer, it cannot fail to arrest the attention of those to whom it is pointed out. A coal field may be represented, in a popular description, as consisting of a succession of alternating strata of coal and sand-stone, &c.: which, having been originally deposited in a basin-shaped cavity, in such a manner as to be at the same time parallel to the concave surface of the basin and to each other, have been subsequently broken up by some force that has thrown the planes of the ruptured masses into various directions. Now, had the strata remained undisturbed, a very considerable proportion of the coal which is now quarried would most probably never have been obtained by human industry: for, the strata dipping down from the circumference towards the centre of the basin, that perpendicular depth, beyond which it is practically impossible to work the coal, would soon have been reached in the operation of mining. But, in consequence of the rupture and consequent dislocation of the strata, many of those portions which were origi nally deposited at such a depth beneath the surface as would have rendered the working of them impossible, have been thrown up to the very surface; and thus have become available to the miner.

SECTION IV.

The general Uses of Water.

ONE of the earliest political punishments of ancient Rome affords an indirect but very remarkable proof,

of the immediate importance of the elements of fire and water* to human life: for this punishment consisting, in part, in an interdiction from the use of water, compelled the individual so punished to fly from his native neighbourhood, in order to obtain that necessary article of support elsewhere: and, hence, banishment and interdiction from fire and water became synonymous terms. There are few who have not experienced the uneasy sensation occasioned by even a temporary privation of this necessary: and the death that ensues upon a continued privation of it is, perhaps, of all modes of death the most dreadful. This we learn from the occasional accounts of individuals who have escaped from shipwrecks, in which their companions had perished amidst the agonies of thirst. And it is said of those unhappy victims of a barbarous punishment, in Persia, (who being immured in masonry as to every part of their body but the head, are left to perish in that state,) that they terminate their last hours, perhaps days, in incessant cries for water.

The necessity of this element for our support may be antecedently inferred, on philosophical principles, from an examination of the physical composition of any animal body; of which, in by far the greater number of instances, more than three-fourths of the whole weight are due to the presence of water. This water of composition may be easily separated by the application of a moderate degree of heat, or even by spontaneous evaporation at a common temperature,

* An apology will hardly be required for applying the term element to a substance, which though it has long been experimentally ascertained to be a compound, will in a popular view be always considered as a simple body; especially if it be remembered that even among the ancients this term did not necessarily imply that the substance so called was absolutely a simple or uncompounded body. It was sufficient with them, that, in all the known processes and phenomena of nature, the substance presented itself under the same essential form: but they were prepared to allow that elementary bodies (Taxi) might possibly be resolved into absolutely simple principles (¿gxaí.)

without any further decomposition of the body; the muscles and skin consequently shrinking to such an extent, as to give the whole frame the appearance of a skeleton, enveloped, as it were, in parchment. Such a result is occasionally observable in human bodies which have been deposited in dry cemeteries; and is by no means uncommon in the case of small animals, as rats, for instance, which having been accidentally wedged in between a wall and a wainscot, are subsequently found in the state above described. An experiment of a very simple character in itself, and very easily made, will serve to ascertain, not only the proportional quantity of water of composition contained in some forms of animal matter, but also the properties communicated by the presence of that element thus combined. Every one has noticed the opaline or milky appearance and the remarkable elasticity of cartilage, or gristle, as it is more commonly called: which characters depend on the water contained in it; for if a piece of gristle, the weight of which has been previously ascertained, be exposed to the air of a warm room, it will at the end of a few hours have lost a portion of its weight; and will have become nearly transparent, and entirely inelastic: and if, in this state, it be immersed in water, it will gradually recover its original weight, and also its elasticity and opaline appearance. If, instead of gristle, a piece of boiled white of egg be employed, the same results will be observable; for, together with loss of weight and elasticity, it will become brittle, and nearly as transparent as pure amber: and on the other hand, by subsequent immersion in water, its original properties will be soon restored. By experiments nearly as simple as those above mentioned it may be demonstrated, that all the liquid and solid parts of an animal, with some few exceptions, contain or consist of more than three-fourths of their weight of water: the importance of which element in the mere composition of our body is hence directly evident.

But if we would have a familiar illustration of its importance in the daily and hourly occurrences of life, let us in imagination accompany an individual of moderate rank and condition in society, from the time of his rising in the morning till the hour of sleep at night, in order to observe the utility of water in administering either directly or indirectly to his various wants and habits. How great is the comfort, to say nothing of the salubrity of the practice, which results to him from the application of water to the surface of the body, by means either of the bath or any simpler process! and, again, the change of the linen in which he is partiarlly clothed is rendered equally comfortable and salutary, in consequence of its having been previously submitted to the process of washing. The infusion of coffee or of tea, which is probably an essential part of his earliest meal, could not have been prepared without water: neither could the flour of which his bread consists, have been kneaded; nor the food of his subsequent meal, the broths and most of the vegetables at least, have been rendered digestible, without the aid of the same fluid; and with respect to his common beverage, whether milk, or any form of fermented liquor, water still constitutes the main bulk of that beverage.

So far the use of water is directly and immediately necessary to his comfort and subsistence: but its indirect and remote necessity is equally observable in all that surrounds him. There is scarcely an article of his apparel, in some part of the preparation of which water has not been necessarily employed; in the tanning of the leather of his shoes; in the dressing of the flax of which his linen is made; in the dyeing of the wool of his coat, or of the materials of his hat. Without water the china or earthen cups, out of which he drinks, could not have been turned on the lathe; nor the bricks, of which his house is constructed, nor the mortar by which they are cemented, have been formed. The ink with which he writes, and the paper which receives it, could not