moving power; and though it would appear, to the man who was ignorant of its properties, the least probable of all the attempts that have been made to obtain a power sufficient to counteract the impediments to motion resulting from natural causes, yet it is infinitely the most efficacious and controllable. When rain falls upon the surface of the earth, it remains a short time, and disappears. It may have been thought by some unnecessary to investigate the cause, but the observer has satisfied himself with the supposition that it passes through the soil into the interior of the earth. There are, however, some strata through which the water cannot be filtered, strata which are impervious to its passage, and over their surface it passes as it would over a basin of oil. The rapid disappearance of the rain that falls on the earth cannot, therefore, in all cases, be attributed to the process of filtration, but is the result of that calorific influence of the solar rays, which, heating the surface of the earth, quietly carries away the redundant moisture as an invisible vapour.

The same process is in operation from the surface of all oceans, seas, and other masses of water; were it not for this, the amazing body of water which the Mediterranean Sea, for example, receives of the many rivers and tributary streams that flow into it, would necessarily raise its level. But no such effect is produced; there appears, on the other hand, to be a larger quantity evaporated from its surface than is carried into it by these rivers and streams, for there is a constant current of water rushing from the Atlantic, through the Straits of Gibraltar.

This is one of those wise provisions of the Creator, by which the continuance of vegetable and animal life is effected. But who, in the consideration of this phenomenon, or the almost analogous one of vapour rising from a boiling fluid, could ever imagine, from the knowledge of it, the application of steam as a moving power?-yet the philosopher, by continued investigation, ascertains the laws of action and of change, and at last invents the steam-engine

The application of the steam-engine is scarcely less remarkable than its invention. It has relieved man of part of that curse which rests upon him; "by the sweat of thy brow shalt thou eat bread." It saws his timber, and forges his iron; constructs the materials for his clothing, and grinds his corn, leaving him little more than a spectator of its marvel

lous operations. But its most remarkable application is that by which it becomes the source of locomotion. It ploughs the mighty waters in its own strength, and virtually connects remote cities and nations, in spite of distance and the obstacles which nature herself has interposed. The railway and the steamboat give an importance to this and succeeding ages which cannot be too highly estimated. In order that despotism should be destroyed, and Christianity be established, a freedom of access between the several sections of the human family is almost essential. The means have been already provided, and the time, we trust, not far distant, when, by their combined influence, all nations will be united in the bonds of a catholic philanthropy, if not of a common faith.

If the accuracy of these remarks and deductions be admitted, the importance of physics will not be denied. The works of God are in all things our model; and when we attempt to apply natural agents to accomplish our purposes, we only imitate that which is constantly going on in the material world. Men are accustomed to boast of the profundity of their knowledge, and the extent of their influence over natural agents, but their efforts are like those of the child, who blows a soap bubble to mimic the upward flight of the aeronaut. The philosopher is but nature's schoolboy, and his efforts are but attempts to understand and apply the agents by which God governs his material creation. All true science is written on the page of nature; and the man who can explain the phenomena by which he is surrounded, and the character and habits of the causes which give them birth, is in every respect a philosopher. In this nature God has in some degree developed his own character, but he has thrown a shade over it, as though to preserve it from the incurious gaze and profane violation of the indifferent and contemptuous. Mind is not less under the guidance of law than matter; and if there be one principle more distinctly developed than any other, it is the necessity of a means to a result. A casual or careless attention to one or two series of phenomena is not sufficient to determine their origin, and much less to ascertain the nature and activity of those causes by which matter universally governed. The human mind has never arrived any important discovery, but by slow and progressive

We have not a single instance of the discovery of

a valuable philosophical fact by conjecture; and had this statement been known and appreciated by the schoolmen of Greece, Rome, and the middle ages, the modern philosopher would be more engaged in teaching than in learning. Experiment is the foundation of philosophy; and for the want of it men have established dogmas for causes, trusting opinions as data, and building hypotheses on unsound foundations. Every science within the boundary of natural philosophy offers proofs of this statement, and illustrates the value of experiment.

But let it not be supposed that in insisting on the high importance of experiment we depreciate the value of mathematical studies. They are important, and necessary to him who desires to investigate with minuteness any branch of physics; but they are not indispensable to an accurate knowledge of principles, and we have acquaintance with many successful experimenters who are utterly ignorant of the mathematics. In one case we entirely trust to intellectual energy and the infallible power of numbers; in the other to reason and to our senses, which, though they offer a readier, and generally a more appreciable species of evidence, involve at the same time greater liabilities to error. The mixed method of investigation is, therefore, always to be preferred.

The reading public, though not so opposed as it once was to scientific research, is not to be attracted by mathematical erudition, or the statement of prolix propositions, but must have plain reasons, or experiments, before it is willing to admit the statements of those who pretend to teach philosophy. The greater number of readers are unable to appreciate mathematical demonstrations; and there can be no doubt that their general use in elementary works, and the unpopular manner in which scientific truths were explained, have tended to prevent the progress of scientific knowledge. We must interrogate nature by experiment, availing ourselves of the assistance of the sciences of quantity and number, as useful auxiliaries in the study of the more complex principles of motion as exhibited by various agents; but, in the explanation of phenomena, the simplest methods of demonstration ought to be used, and the most familiar illustrations should be chosen to allure and encourage him who is in search of information.

These hinderances to the progress of scientific knowledge have been in our day removed; and though the process of

education has derived little advantage from it, the fault is with the teacher rather than the public. The faculties, capabilities, and condition of the mind are never studied, but ten years of vivacious and energetic being are occupied in the acquisition of words. A new inhabitant of earth, surrounded by strange and novel appearances, governed by a curiosity to know something of that which affects his senses, and produces the sensation of pleasure or of pain, is checked in every inquiry that he may make, and is compelled to cultivate a single faculty, and to attain a knowledge of words and criticisms; is in fact doomed to pass his existence in a world which, for aught he knows, has not a single attribute of perpetuity. We may be permitted, from experience, to pity the mind that is doomed to a lengthened slavery in the acquisition of words, and the improvement of memory, when observation and curiosity are the predominating principles of mental activity. To deny the value of an acquaintance with foreign languages, and even of those which are so improperly called the dead languages, since they, in a great measure, form the literary taste of our own and other nations, would be to deny the value of accuracy of style and expression, energy of thought, bursts of eloquence, sentiments of morality, and knowledge itself. There are minds that break the trammels of system, and, possessing a knowledge of languages and literary elegance, add to it a knowledge of men and of things which gives lustre to learning; but minds of less strength are too often buried under lexicons and grammars, or acquire a distaste for all species of knowledge. The error is not in the acquisition of languages, but in studying them exclusively at a wrong time. It is not our intention to advocate the importance of scientific knowledge, by misrepresenting the claims of literature, but rather to urge the necessity of their union, and the combination of their efforts; for though "the mind is the standard of the man," it is ever desirable to remember that it dwells in a material tabernacle, and is acted upon by material causes.

Although much has been done calculated to diffuse knowledge, education is still in a great measure confined in its objects, and frequently injurious in its effects. The establishment of philosophical institutions has certainly a tendency to correct the evils which flow from the system of education adopted in our schools, and it is now little less than culpable

negligence in a teacher if he does not avail himself of the aids which these societies offer. But we can expect little improvement in the system, until both the teacher and the public feel the necessity of blending literature and science, and of regarding the peculiarities of mind which may distinguish individuals. It is seldom that the faculties of mind are uniformly developed; and although it may be necessary to correct the inordinate passion which is sometimes indulged for a particular pursuit, yet it is evident that to repress it altogether would be to destroy the energy of a mind, and to create a disgust for learning itself. Scientific knowledge is at least as important as ancient literature, but we should as much regret an exclusive attention to it in our schools, as we do the system now adopted of only teaching the classical languages. All minds are not equally suited for the same pursuit ; and unless some circumstance in after life should rouse to activity in that department of knowledge for which the individual is by nature adapted, the energies of his mind must be irretrievably lost to society.

CHAPTER I.

THE EARTH IN RELATION TO THE UNIVERSE.

No science can be perfectly understood by a person who has confined his attention to the facts it teaches, for philosophy may be compared to a golden chain, which men are compelled to examine link by link, unable at once to perceive the connexion which exists between its parts. So, if we attempt to explain the phenomena we witness upon the earth's surface, without previously acquainting ourselves with the conditions of the body, and the relation it bears to those bodies by which it is surrounded, we shall always be sensible of the incompleteness of our knowledge, and may, in many instances, be ied into error. All the causes acting upon the surface of the earth may be in themselves suited to sustain and nourish the creatures by which it is inhabited; but the relation it bears to other bodies may, for aught the mass of mankind know,