is, that, of late years, the leading departments of literature, both poetical and critical, have been almost exclusively in the hands of Scotchmen. With such advantages, it can be no wonder that Burns is still overvalued. But it is to be hoped for the credit of English talent, that the literary ascendency of our ingenious neighbours will not endure for ever : in process of time their domination may be superseded, and, with the sovereign influence, appear destined to fall the favourites whom the sovereign influence has npborne.

A COURSE OF LECTURES ON NATURAL PHILOSOPHY, AND THE MECHANICAL ARTS. BY THOMAS YOUNG, M.D. &c. 2 Vols. 4to.-1807,

THE accumulation of knowledge, which the observations and the exertions of about thirty centuries have produced, exceeds, in an unappreciable degree, the capacity of a human being. Though divided into branches under appropriate denominations, and though a single individual generally directs his attention to not more than one or two of those branches; yet it can but seldom be said, that he becomes thoroughly possessed of the former; nor can it be denied, that the difficulty of comprehending and retaining increases in proportion as science advances. But the same industry, which has ascertained a multitude of useful facts, and has thus extended the limits of the arts and the sciences, has likewise contrived means of assisting the mind, both in the comprehension, and in the retention, of those facts. The former of these objects is attained by clear, rational, and methodical explanations; --the latter, by arrangements in written repositories, wherein any particular kind of information may be easily and regularly obtained.

The late rapid advancement of Philosophy in all its branches, having frequently demanded a renewal of those books which profess to explain its principles and to record its valuable discoveries, various such works have accordingly been produced, and among those, it cannot, upon examination, be denied, that one of the best which the public has re ceived, is the work which forms the object of the present account. Two bulky quarto volumes, although too large for an elementary treatise, and too small for a complete and extended view of the subject, will, nevertheless, be found to contain a prodigious stock of information, far exceeding the quantity which might be reasonably expected from the size of the volumes, or from the labour of a single individual. A work so large, so comprehensive, and yet so concise, must naturally afford ample scope both for criticism, and for commendation. But the voice of impartiality, which weighs each separate part, and determines the result of the whole, is compelled to pronounce a most favourable report on the merit of the performance.

The first volume, consisting of about 800 pages, contains (after a preface and an ample table of contents) sixty lectures in three divisions, under the titles of Mechanics, Hydrodynamics, and Physics; each of which divisions comprehends twenty lectures. Those lectures were compiled for the purpose of being read at the Royal Institution, to which place Dr. Young was appointed Professor of Natural Philosophy, and where he accordingly read them during two successive years. They were afterwards revised, corrected, and enlarged, by the addition of the most recent discoveries, and, under that.. form, they were finally offered to the public in the year 1807. The same volume likewise contains 43 copper plate engravings, to each of which a short explanation is annexed in the opposite page, and which exhibit the delineations of a vast number of instruments, results of experiments, natural phepomena, and diagrams for illustration. Some of the figures

which relate to optics, are neatly coloured. The plates are full, but the figures in general are small, rather too much so for most readers.

In the compilation of these lectures, Dr. Young has not only undertaken to explain the chief, or leading principles of natural philosophy; but he has also endeavoured to mention all the collateral or dependant subjects, such for instance, as the application of mechanics, of hydrostatics, of astronomy, of optics, &c. to the common purposes of economy, to the arts, and to manufactures. He has, in truth, embraced a much greater variety of subjects than is usually explained in a course of philosophical lectures, or in philosophical treatises; but he has treated them in a manner neither too profound, nor too particular; having justly adapted them to the purpose of giving a general information of those matters to a mixed company, such as may be expected to attend the Royal Institution. To a company of that description, the intricacy of strict demonstrations, the long lists of facts of certain de nominations, the minute numerical determinations of weight, of temperature, of refraction, of expansion, of hardness, of gravity, of transparency, and so forth, will always prove both tedious and useless; it being hardly to be expected that the hearer should follow a long demonstration without interruption, or that he could impress on his memory a train of new names, and of particular numbers, in the course of a verbal recitation.

It may be obviously observed, that in preparing these lectures for the press, such statements as have been mentioned above, might have been subjoined either in the text, or by the way of notes; but Dr. Young with great propriety reserved them for the second volume, which will be noticed in the sequel.-Let us now take a nearer view of the contents of the first volume, or at least of some parts of it; for the uniformity of style supersedes the necessity, and the limits of our publication renders it impracticable, to follow this author step by step throughout his extensive work.

It has been frequently observed, that most of the primary notions of philosohpy, and such as may seem to be the simplest, are the most difficult to be explained with verbal precision, or with complete satisfaction. The reason may probably depend upon the want of simpler ideas, by the combination of which, the desired explanation may be effected. On this account it frequently happens, that the comprehension of a particular subject is rendered much more intricate and perplexed by the very same length of illustration, which is intended for its complete elucidation. Dr. Young's definition of Motion in the second lecture is ingenious; and, had he left it insulated, the slightest attention on the part of the reader, might have compensated for the exceptionable part of its general application. "Motion, (he says,) therefore, is the change of rectilinear distance between two points." He then proceeds to observe, "that two points are necessary to con"stitute motion; that in all cases when we are inquiring "whether or no any body or any point is in motion, we must "recur to some point which we can compare with it, and "that if a single atom existed alone in the Universe, it could " neither be said to be in motion, nor at rest."

It may be easily perceived, that the original definition of motion is sufficiently satisfactory, but that the subsequent part, together with a great deal more, which we might have transcribed, seems to involve the mind of a novice in a cloud of doubt and perplexity.---The like observation might also be applied to some other definitions.

The seventh lecture, on Pressure and Equilibrium, is peculiarly well executed; the difference between pressure and momentum (an abstruse subject) being pointed out as well as the present state of knowledge seems to admit of. The simple mechanical powers are likewise briefly and clearly explained in the latter part of the same lecture.

The tenth and the eleventh lectures are some of those which treat of subjects unusual in a course of philosophical lectures. The former treats of Drawing, Writing, and Measuring; the

latter, of Modelling, Perspective, Engraving, and Painting. But though those subjects are treated in a concise, and sometimes in a superficial manner; yet they furnish good examples of the application of mechanics, and serve, at the same time, to relieve the mind from the continual attention to theoretical precepts. Nearly the same observations are applicable to the fourteenth lecture, wherein the principles of architecture and carpentry are explained, and to the seventeenth, which describes the construction of chronometers, or time-keepers, giving an account of their gradual improvements, and their peculiar merits.

The twentieth lecture, which contains a concise history of Mechanics, and concludes the first grand division under the name of Mechanics, is peculiarly well adapted to the inclination of general readers.

There is a competition, -a sort of rivalship, among human beings, which renders them extremely fond of personal anecdotes. The unusual actions, whether laudable or blameable, of other individuals, their prosperity, or their misfortunes, seldom fail to excite interest and curiosity; for by a natural application to ourselves, our satisfaction, our emulation, our caution, or our astonishment, is called forth, whence new actions frequently arise. In scientific histories, where theoretical or practical subjects are connected with personal anecdotes, the latter, by a natural connexion of ideas, help to impress the former on the mind of the hearer. Thus the idea of burning-glasses generally suggests the remembrance of Archimedes, and Proclus, who are said to have burned the vessels of their enemies by means of reflectors. Thus also the name of Newton is scarcely separable from the idea of the general gravitation of matter.

Dr. Young begins his lecture with the origin of Grecian learning in Egypt, and then proceeds to mention the Ionian and the Italian schools, Pythagoras, Democritus, Archytas, Aristotle, Epicurus, Archimedes, Vitruvius, Bacon, Galileo,