diversities of the bodies. But above all, the attractionists were in raptures with that which they perceived, or thought they perceived, in electrical bodies. This could not be mistaken, and it acted exactly as in the planets, diminishing in the circuit, as it augmented in distance. Unluckily an experimental philosopher came and knocked all this on the head; and by fastening a little ball of wood at the extremity of a cord of a thousand or twelve hundred feet long, he discovered, that if an electrical tube was applied either to the middle or at one end of this cord, the spangles of gold placed at the other end, under the wooden ball, clung to it as suddenly as if the electricity had acted within a foot of the tube. One of our learned Newtonians has made an hundred experiments upon the loadstone. After infinite precautions and calculations, he frankly owns the attraction failed him, when he had occasion for it, and that he could make nothing of itt.

I shall here end the history of systematical philosophy, because it is of little use to give a more full knowledge of it, and perhaps may be dangerous to young people, by busying their minds upon systems, which cannot fail, in spite of all our exertions, to present some phæ nomena to our thoughts, which is a very great prejudice to the progress of true philosophy; either because it is not easy to get rid of certain generalities, or that we see every thing conformable to our prejudices. Experimental philosophy is the only one which has been of use to human society; and as we have shown that the advantages flowing from it are innumerable, so we cannot recommend for the study of philosophy, a more prudent method than that which the members of the Royal Academy have followed for our instruction,

* Mr. Muschenbroek.

These considerations the reader will find more minutely examined in the introductory chapter to the department of CHEMISTRY, which will enter into the second division of the present work. It will there appear that many of the objections here offered to the simplicity of the general, and now still farther established laws of nature, have been removed by experiments and observations not known at the time the ingenious paper here copied was written: and that most, if not all, the peculiar attractions of matter are resolvable inte different modifications of the general attraction of gravitation.

It is to the second part of the present work that we have also to refer the reader for an account of such astronomical instruments, maps, charts, globes, orreries, and projections, as are most curious or in other respects worthy of notice.-Editor.

They have never, as a collective body, given their approbation to any one general system. They are fully persuaded, that if man be allowed to arrive at a thorough knowledge of nature, it can be only by treasuring up experiments and facts, for a great length of years; and should even this thorough knowledge be denied to our condition, experiments at least, and the knowledge of most minute things, will procure, as is daily experienced, various benefits to public society. This very judicious principle, which they have always looked upon as a rule, and the nature of the different functions which these learned men have divided among themselves, are accurately founded on the necessaries of life, and the extent of our capacities. They go farther: the experimental philosophy which they have brought into esteem is the only useful one, because it is the only one conformable to our condition: which, without offence, we may name, The System of Providence.

The experience of six thousand years is certainly sufficient to teach us what is possible and what is forbidden. While man, in his inquiries, was busied in things submitted to his government, his endeavours were always rewarded by new discoveries. Whenever he would pry into the interior structure of the parts of the universe, the motion of which is not submitted to his care, his ideas have been fantastical and uncertain. Let him study the measures of magnitudes, and the laws of motions; not to pace out the heavens, or to weigh the solid bodies of the planets, but to know the order of his days; let him observe the relation of the aspects of the heavens to his habitation, the progression of light in the modification in which it is presented to him; the use he may make of the equilibrium of liquids, of the weights and velocities of the bodies of which he is master, of all the experiments which come within his view, and especially ander his hand; in a word, let him apply experiments to the necessaries of life, and he will have an unerring philosophy, replete with great advantages. But to undertake to determine the cause which governs the motion of the universe, and to penetrate into the universal structure, and the particular parts of which it is composed, is to forfeit the honour of improving his patrimony in order to run after shadows. It is neglecting treasures which are open to us, and obstinately persisting to knock at a door which has been shut against us these six thousand years. This is no conjectural opinion, but a visible truth of experience, that God has given us great facility and intelligence in things which we ought to manage; and, on the contrary, that those to which God

himself gives motion and action, without entrusting the conduct to our care, he has concealed from our knowledge. For example, we are ignorant of the structure of our stomach, because God has eased us of the care of its digestion. In vain would the most able anatomist direct his digestion; all very often goes contrary to his wishes. On the other hand, we have in our senses many watchful and faithful monitors, opportunely to direct what nourishment is proper for us. Why then have we so many methods to be acquainted with our nutriment, if it is not that the care of seeking and chusing it, is committed to us? And why, on the contrary, do we not know how to digest, if it be not that God has evidently willed our digestion to be performed in us without our direction? God, who has spared us that trouble, has denied us the knowledge of the mechanism which forms the flesh and the fruits that we eat, as well as the mechanism which extracts the juices from them for our nourishment, This knowledge would have distracted us. We attain the age of four score and ten, without knowing what digestion is, or what is the action of the muscles. We have been served without any care on our part. Had we thoroughly known the structure of our stomachs, we should have been for directing its functions. God has not allowed this knowledge to man. He ordained him to be otherwise employed. If then this mechanism be hid from him, lest it should multiply his cares, will be acquaint him with the structure of the world, the motion of which is not committed to his charge?

I can scarcely be of opinion, that the modern philosophers have rightly conceived the plan of the Creator, in having less esteem for the knowledge which we attain by our senses, than for what they imagine is to be acquired by a profound meditation. One example will make me understood.

The common sailor knows nothing more of the loadstone than what his senses inform him, viz. its tendency towards the north pole. This is the sum of his knowledge. The philosopher would know the cause of this phenomenon; he employs the effluvia of its pores in spiral lines, the attractions, the repulsions; and after several years use of his mechanics, his geometries and calculations, he either acknowledges that he himself knows nothing of the matter, or else has the mortification to find that nobody approves of his system. The systematical philosopher, who thinks himself ignorant if he know not the cause of what he sees, passes his whole life in the pursuit of possibilities, and becomes useless to the rest of mankind by being buried

alive in his closet. The sailor makes use of what his senses inform him of, the direction of the loadstone towards the north, and by its assistance voyages to the end of the world. Make choice of ten thousand other informations of fact, and you will hardly find one of them but what is of service. Our fortunes will be better in proportion to this sort of knowledge. Would you seek after the causes of these effects? You will meet with nothing of certainty or use. Can we, after this, mistake the intention of God, in the measure of understanding which he affords us for our present instruction?

It is evident that we have no universal knowledge. The objects of our pursuit are scattered round us upon the earth and in the heavens. God has given us, together with eyes and understanding, a fund of curiosity which stimulates us from one object to another, that new experiments may enable us to procure new conveniencies for our brethren; and that every thing upon earth may, by degrees, be put to the best use for the profit of mankind. But though a man can go on a stretch from Brest to Pekin, it does not follow that he can go to the moon; or though he have a principle of power in his hands, that enables him to support piles of oak, and great blocks of marble in the air, this is no reason why he should attempt with his levers to make the moon fly off from her orbit, or to fix his pullies to the body of Jupiter, to rob him of one of his satellites. As man's strength is limited, so likewise is his knowledge, and these bounds are suited to his wants. He meets with opposition, every where, when he enters upon idle speculations. But he proceeds from discovery to discovery, which discoveries work miracles, when he employs himself in making the best use of that which is about him. Our reason is always attended with success in uniting the truths of experience with the necessities of life, in making a prudent use of the benevolence of the Creator, and in giving him the glory, This is the sum total of human knowledge.

[Abbé Le Pluche. Spec. de la Nature.]

We have given the above, not because we approve of the philo. sophy of the vortices, but as containing a tolerably fair view of the theories that preceded it; and a curious specimen of the different modes by which this philosophy was adhered to, in opposition to the doctrine of universal attraction, as long as it could possibly be defended.-Editor.

BOOK II.

GEOLOGY.

CHAPTER I.

GEOGNOSY; OR, THE DOCTRINE OF THE ORIGIN AND GENERAL STRUCTURE OF THE EARTH.

UNDER the Wernerian system of Mineralogy, the term Geology is altogether relinquished, or only incidentally referred to, as importing abstract and imaginary speculations concerning the formation of the Earth: while the immediate branch of science, designed to be glanced at in the present chapter, is denominated Geognosy. We have no objection to the last term in the sense thus signified; but shall restore the term Geology, and employ it, as its derivation will readily justify our doing, in a classific form, importing the general doctrine of the earth in its insentient or unorganized frame; and consequently as comprising equally its subterranean, superficial, and atmospherical phænomena.

Before we enter, however, upon these particular parts of our subject, it becomes us to offer a brief view of what, so far as we are capable of determining from an actual survey of nature, appears to have been the origin of the earth, as to its present structure and constitution, comprising that introductory branch of geological science, which, as we have already observed, professor Werner has distinguished by the name of Geognosy.

The object of Geognosy is to unfold the general make of the globe; to discover by what causes its parts have been arranged; from what operations have originated the general stratification of its materials, the inequalities with which its surface is diversified,