we may reasonably hope, that the dreaded evil of a check sufficient to stop its current and throw it back upon itself, is, if not altogether chimerical, at least too remote to justify the alarm of the present generation.

The third subject of our author, is the decomposition of rocks. Upon this, as upon the two subjects just treated of, he entertains an opinion, at variance with the doctrine of most geologists, but certainly more consistent with established facts, and more consonant to the suggestions of sound reason. He does not deny, that rocks are liable to decomposition; but he contends, and we think abundantly proves, that it is not a process so general and so rapid as many seem disposed to believe.' Among many other ingenious arguments, to show the absurdity of the generally received opinion, we select one, which is in itself enough to decide the question, The agents of decomposition, necessarily acting upon the surfaces of rocks, would first seize upon the prominent points and angles, and show their effects, by reducing these to a rounded appearance. This is the universal effect of the application of the principal agents of their decomposition, or more properly their disintegration, which are, alternate heat and cold, moisture and dryness; and the process of the oper ation is too obvious to require explanation. This, then, being the fact, and rocks being almost universally found to retain all their points and angles, it follows that the process of decomposition has not commenced, or that it is too slow to author ize the prevalent opinion, that the greatest part of the substances which constitute most soils proceed from the decomposition of the rocks surrounding or lying under them.' The whole chapter upon this subject is well worthy the attention of those visionary theorists who seem more inclined to create worlds of their own, than patiently to examine the phenomena of that, in which they are placed.

Having thus laid before our readers a view of the principal subjects treated of by Mr. Hayden, it remains only to speak of the manner in which his work has been executed; and here we cannot help regretting, that literature and science do not always maintain that close connexion, which would ensure the mutual esteem and veneration of their respective. votaries. The style of this volume will deter many from going through it, who would willingly subscribe to the high claims of the author, as a profound philosopher. It will be

seen at once, that MHarden has been more accustomed to think deeply, than to express his thoughts; and that he has paid much more attention to the uses, than to the graces of composition. This is not the first time that his name has been before the public. In Professor Cleaveland's admirable work on mineralogy, we find it of frequent recurrence; and this circumstance alone is a passport to our notice. But no one who reads these essays, freed from the trammels of fastidious criticism, will need to be told, that their author merits his respect whether he had ever heard of him before or not, he would be ready to acknowledge the honour of his acquaintance, after a candid consideration of his claims.

Mr. Hayden's defective style, however, much as it might be censured, is not the greatest fault of his work. It exhibits a want of method and arrangement, altogether inadmissible in a work of science. The chapters, into which it is divided, are without heading; and the divisions are made, in several instances, in the middle of an argument, where the sense would hardly call for a separate paragraph. The chapters from six to eleven, inclusive, should either have been embodied in the first, or have been added as an appendix, since the reader is compelled to refer to them, before he can understand the mode of reasoning adopted in the first. The different subjects are mingled together without order, and the necessary consequence is, that the same arguments are frequently repeated.

We have before expressed our disapprobation of the very free use he has made of quotations from other writers. They make up, indeed, so much of the book, that the purchaser may have just cause of complaint, that he has been made to pay, for what was already his own. Nor is he always correct, in his references to the authors of these many quotations. He sometimes gives credit to Mr. Rennell, for the opinions of Herodotus, and to Cuvier, for the sentiments of M. De Prony. But this has, undoubtedly arisen from inadvertence, as it is evident Mr.Hayden has studied his subject with too much attention, not to be acquainted with the opinions of all the writers of note, who have touched upon it. Upon the whole, we are disposed to regard the Geological Essays' as well deserving an attentive perusal. We would especially recommend the selection of queries embraced in the Agenda,' to the notice of every scientific traveller, and man of leisure.

ART. VIII.-Histoire de L'Astronomie ancienne et moderne De J. S. Bailly, dans laquelle on a conservé littéralement le texte historique de l'Auteur, en suprimant les details scientifiques, les calculs abstraits, les notes hypothétiques, peu utiles à beaucoup de Lecteurs, et aux Elèves auxquels ce Livre est spécialement destiné. 2 vols. 8vo. pp. 866. A Paris, Chez Bernard, 1805.

ASTRONOMY is certainly the boldest and most comprehensive of all our speculations. It is the science of the material universe considered as a whole. Though employed upon objects apparently withdrawn from the sphere of human action and pursuit, it teaches us, nevertheless, that these objects materially affect, nay constitute, our physical condition. The wide-spreading firmament, while it lifts itself above all mortal things, exhibits to us that luminary, which is the light, and life, and glory of our world, and when this retires from our view, is lighted up with a thousand lesser fires, that never cease to burn, that never fail to take their accustomed places, and never rest from their slow, solemn, and noiseless march. Among the objects more immediately about us all is vicissitude and change. It is the destiny of terrestrial things to perpetuate themselves by succession. Plants arise out of the earth, flourish awhile and decay, and their place is filled by others.' Animals also have their periods of growth and decline. Even man is not exempt from the general law. His exquisite frame, with all its fine organs, is soon reduced to its original elements, to be moulded again into new and humbler forms. Nations are like individuals, privileged only with a more protracted existence. The firm earth itself, the theatre of all this change, partakes in a degree of the common lot of its inhabitants, and the sea once heaved its waves where now rolls a tide of wealth and population. Situated as we are, in this fleeting, fluctuating state, it is consoling to be able to dwell upon an enduring scene, to contemplate laws that are immutable, an order that has never been interrupted, to fix, not the thoughts only, but the eye, upon objects that after the lapse of so many ages, and the fall of so many states, cities, human institutions, and monuments of art, continue to occupy the same places, to move with the same regularity, and to shine with the same pure, fresh, undiminished lustre.

As the heavens are the most striking spectacle that presents itself to our contemplation, so there is no subject of philo

sophical inquiry, which has more engaged the attention of mankind. Its history carries us back to the earliest times, and introduces us to the languages and customs, the religion and poetry, the sciences and arts, the tastes, talents, and peculiar genius, of the different nations of the earth. The ancient Atlantides and Ethiopians, the Egyptian priests, the magi of Persia, the shepherds of Chaldea, the bramins of India, the mandarins of China, the Phenician navigators, the philosophers of Greece, and the wandering Arabs, have contributed to the general mass of knowledge and speculation upon this subject, have added more or less to this vast structure, the common monument of the industry, invention, and intellectual resources of mankind. They, whose imaginations have wandered up to the sphere of the stars, like those who have visited unfrequented regions on the earth, have left there, as in a sort of album, some memorial of themselves and of the times in which they lived. The constellations are a faithful picture of the ruder stages of civilization. They ascend to times of which no other record exists, and are destined to remain when all others are lost. Fragments of history, curious dates and documents relating to chronology, geography, and languages, are here preserved in imperishable characters. The adventures of the gods and the inventions of men, the exploits of heroes and the fancies of poets, are here perpetually celebrated before all nations. The seven stars and Orion present themselves to us as they appeared to Amos and Homer. Here is consecrated the lyre of Orpheus and the ship of the Argonauts, and, in the same firmament the mariner's compass and the telescope of Herschell.

We remark further, that astronomy is the most improved of all the branches of human knowledge, and that which does the greatest credit to the human understanding. We have in this obtained the object of our researches. We have solved the great problem proposed to us in the celestial motions; and our solution is as simple and as grand, as the spectacle itself, and is in every respect worthy of so exalted a subject. It is not the astronomer only, who is thus satisfied, but the proof is of a nature to carry conviction to the most illiterate and skeptical. Our knowledge, extending to the principles and laws which the author of nature has chosen to impress upon his work, comprehends the future; it resembles that which has been regard. ed as the exclusive attribute of supreme intelligence. We are

thus enabled, not only to explain those unusual appearances in the heavens, which were formerly the occasion of such unworthy fears, but to forewarn men of their occurrence; and, by predicting the time, place, and circumstances of the phenomenon, to disarm it of its terror.

There is however nothing perhaps so surprising in this science, as that it makes us acquainted with methods, by which we can survey those bright fields on which it is employed, and apply our own familiar measures to the paths which are there traced, and to the bodies that trace them; that we can estimate the form, and dimensions, and inequalities, of objects so immense, and so far removed from the little scene of our labors. What would be the astonishment of an inhabitant of one of those bodies, of Jupiter for instance, to find that, by means of instruments of a few feet in length, and certain figures and characters, still smaller, all of our own invention, we had succeeded in determining the magnitude and weight of this great planet, the length of its days and nights, and the variety of its seasons, that we had watched the motions of its moons, calculated their eclipses, and applied them to impor tant domestic purposes? What would be our astonishment to learn, that an insect, one of those for instance which serve sometimes to illuminate the waters of the ocean, though confined by the exercise of its proper organs, and locomotive powers, to the sphere of a few inches, had. by artificial aids of its own contriving, been able to extend its sphere of observation, to the huge monsters that move about it; that it had even attempted, not altogether without success, to fathom the depth of the abyss, in which it occupies so insignificant a place, and to number the beings it contains?

Since astronomy is thus connected with the development of our faculties, it may be a matter of some curiosity to notice a few of the more important epochs in its history. It is considered as properly originating with the Greeks, who were called to Alexandria by the Ptolemies. Before the foundation of this school, no general scheme, with respect to the study of the heavens, had been devised, no enlarged notions had been formed, no means had been found out for precise and accurate determinations, nor could astronomy be said to exist as a science. Those who pretended to study the heavens, were employed in vague notices of the most obvious phenomena. On such a day, an hour after sunset or two hours before