being opposed to positive quantity, we naturally looked for a definition of the latter, but in vain; and being thus left in the lurch, we sought for explanation in the scholium, where we found, that a debt is a negative kind of property, a loss a negative gain, and a gain a negative loss. On the strength of this definition we asserted the other day, that Walsh and Nisbett had gained upwards of two hundred thousand pounds by their late speculations, had, on winding up his affairs, found his losses to be between three and four hundred

work, and the mathematician will find no assistance from this catalogue in selecting a library either for general reading, or for any part which he wishes more particularly to study. Had the writer given himself proper time for this part of his work, he would have done great credit to himself, and been very useful to the public.

Upon the whole this work is an omnium gatherum, such as perhaps has never before appeared. It proves, that the writer is a man of very considerable talent and very extensive reading. From a wish to entertain his audience, he collected together as much matter as possible, but he did not recollect the differ

ence between a lecture delivered in public, and the reading in the closet. In our study we examine every part; we expect to see clear and connected reasoning, just definitions, and proper arrangement. The work will not instruct a beginner, for it is too difficult for him, it will not satisfy one advanced in his studies, as he will seek for information in better works. It is only a proof of great industry and great reading. And as the author has already begun to collect materials for a work in a form nearly similar relating to every department of medical knowledge," we prophecy that the medical world will be as much indebted to him as the mathematical.

ART. III. Lectures on Experimental Philosophy, Astronomy, and Chemistry; intended chiefly for the Use of Students and young Persons. By G. GREGORY, D. D. In 2 vols. 12mo.

DR. GREGORY, now no more, was long known to the public as a writer on the several branches of natural philosophy, and though he had not always the clearest method of explaining the facts upon which the principles of philosophy depend, yet his readers might generally rely upon his judgment in bringing forward only those facts which had stood the test of experiment and observation, and which philosophers had demonstrated as true. The work before us which was finished printing, though not published before the author's death, is very well adapted to the purposes for which it is intended. Some of the lectures, we are told, were originally published in a peri. odical work, [the monthly preceptor we believe:] they have however, been mostly re-written, and adapted to the present state of sci

ence. Excepting in chemistry, and galvanism, the facts in natural philosophy have not greatly varied in the last few years; to the discoveries on these sciencies the doctor was not inattentive, and he has noticed, though perhaps not in so full a manner as he might, the introductory discoveries of Mr. Davy on the fixed alkalies. The greater part of the second volumeis devoted to chemistry. The other topics discussed, are the same, with the exception of electricity and galvanism, with those so often given to the public by Ferguson, and other popular writers. Every man has a different mode of elucidating the same facts, that of Dr. Gregory being so well known to the public, it is needless to say more than that these lectures are among his most popular productions.

ART. IV. An Elementary Treatise on Natural Philosophy, translated from the French of M. R I. Hauy, Professor of Mineralogy at the Museum of Natural History at Paris, by OLINTHUS GREGORY, A. M. 2 vols. 8vo.

THIS work, though but lately translated into English, has obtained a very considerable circulation

in France, and many other countries. on the continent. It was intended by the author as one of those ele

mentary books for which great encouragement is given at Paris, where every means is taken to facilitate the progress of progress of natural knowledge. The English reader The English reader would expect from the title a very different book from that which now claims our attention. With us, in almost all cases, 66 a Treatise on Natural Philosophy," includes regular introductions to mechanics; to hydrostatics; to hydraulics; to pneumatics; and to astronomy. But we find that M. Haüy's work, which does not embrace these subjects, was meant to be studied in conjunction with Biot's treatise on "Physical Astronomy," and Francoeur's "Elements of Mechanics;" hence it may be regarded only as part of a system, and as such it must be considered by us. We shall accordingly point out what the volumes before us contain, in what manner the author has executed his part of the work, and then notice the labours of the translator.

laws to which the Supreme Being has subjected the universe at others, the collection of beings which have sprung from his hands. Nature, contemplated thus under its true aspect, is no longer a subject of cold and barren speculation with respect to morals: the study of its productions, or of its phenomena, is no longer bounded to enlightening the mind; it affects the heart, by kindling therein sentiments of reverence and admiration at the sight of so many wonders, bearing such visible characters of an infinite power and wisdom. Such was the disposition that was cultivated by the great Newton, when, after having considered the mutual connection which subsists among effects and their causes, and makes all the particulars concur to the harmony of the whole, he elevated his mind to the idea of a Creator and Prime Mover of matter, and enquired of himself why nature had made nothing in vain? whence it happens that the sun, and the planetary bodies, gravitate the one towards the other without any intermediate dense matter? and, how it could be possible that the eye should be constructed without the knowledge of optics, or the organ of hearing without the intelligence of sounds?

"The true method to arrive at the

explication of phenomena, is that which was adopted by the same philosopher (Newton;) and to which the sciences are indebted for the rapid progress they have made, and are still making every day in the hands of so many learned men. No

We must observe that different as M.Hauy's method may be in discussing these subjects, from what we should expect in a treatise by an Englishman, yet he has not failed to render tribute where tribute was due, to ascribe to our countrymen as well as to his own the discoveries to which they have a claim. Briton, boasting in the alliance which his birth has given him to the illustrious Newton, can think or speak more highly of this great man than M. Haüy in his general introduction. A passage to this purpose we shall transcribe, not more for the sake of exhibiting the author's candour, than for the opportunity it gives of shewing that the French philosophers are not all atheists, as has sometimes been in

ferred!

"This word Nature, which we so frequently employ, must only be regarded as an abridged manner of expressing, sometimes the results of the

That it may be better conceived in what this method consists, it will not be useless to establish in this place, clearly and precisely, the idea which should be formed of that which is called a theory, to make its design and its advantages sensible, to trace the limits by which it is separated from a system, and to prevent the confounding of the productions of genius which exhibit nature such as it is, with those of the imagina tion, which shapes it as it will.

The object of a theory is to connect to a general fact, or to the least possible number of general facts, all the particular facts which seem to be dependent. Our first steps in the sciences are directed towards the research of facts: our next employments are to describe them exactly, to verify them strictly, and to

multiply them. The former are given by simple observation, and are presented as of themselves to an enlightened attention; the latter are the results of experiments made with that care, that address, and that sagacity, which this kind of researches require. All these facts, discovered at different epochs, and by different observers, stood, at first, as isolated particulars; some of them even presented themselves under the air of paradox, and seemed to stand in contradiction with the other facts of the same kind. Thus the ascent of water in the body of a pump, limited to the altitude of 33 feet, shews the defect of the obscure and unintelligible physics of that time, which attributed this ascent to a pretended horror of nature for a va cuun. But at length appeared the genius, to which was reserved the praise of re-uniting all these scattered links, and forming a continued chain, which would shew their descent and mutual dependance.

"Thus observation and theory concur equally to the certainty and to the developement of our knowledge. Each has a flambeau in her hand: observation directs the rays which emanate from her's upon every fact in particular, in such manner, that the whole is placed as it were in day-light, that it becomes distinctly terminated, and that it is presented to us under its true form: theory illuminates the aggregate of facts, and re-assembles, under the light of her torch, all those facts, at first dispersed, and which seem to have nothing in common; then they assume the air of a family, and appear to be nothing more than different aspects of a single fact."

It is evident that M. Haüy's meaning of the word theory is extremely different from its general acceptations among us, and from that of Mr. Gregory, who, in his own preface, making use of the term in our common English mode, might perhaps have intimated to his readers what was understood by the original author when he used the word. The great business, in physics, is undoubtedly an accurate attention to definitions. If philosophers used the same words and phrases in pre

cisely the same sense, nine tenths
of the disputations that have subsist-
ed between men of science would
never have been known.

ing the most general properties of
M. Hauy sets out with explain-
bodies, as extension, inpenetrabi-
lity, &c. he then proceeds to those
other properties which depend upon
certain forces, as the attraction of·
gravitation, chemical affinity, &c.
Water, air, and electricity, are
the other leading and general heads
of the first volume, and under these
many subjects are brought, which
we should naturally look for in an
elementary treatise. Thus under
the laws of affinity we have a neat
account of those of crystallization
in sections devoted to the conside-
ration of the primitive forms of
crystals:-forms of the integrant
moleculæ, and laws to which the
structure of crystals is subjected.
No man is more capable of entering
well into this subject than M. Haüy,
and we almost wonder that an au-
thor so deeply conversant on a
branch of science which he deems
of such high importance, should not
have devoted more of his pages to
it. His introductory observations
on crystallization will be read with
interest.

"The formation of salts, which takes place daily under our eyes, by the intervention of dissolvents employed by the chemist, is nothing else than an imitation of what is passing in the immense laboratory of nature, and of the manner of operation in the production of all those crystals of different kinds which hang from the interior surface of certain caverns, or are found residing in certain earths.

"Here a very marked difference between minerals and organic beings presents itself. The vegetable, for example, draws its origin from a germ which the form; and the impression of that form is nourishment developes, still retaining its afterwards transmitted by the way of reproduction, to the individuals the succession of which propagates the species. All have their flowers composed of parts