may exhibit, and during the different stages of the moon's increase and decrease, and delineate the dif ferent aspects they may present. When we consider that, by means of a telescope which magnifies 200 times, an object on the moon that measures only 600 yards may be perceived as a visible point, and by one which magnifies 800 times, an object not larger than 150 yards in diameter may be distinguished—we can scarcely entertain a doubt, that a number of interesting discoveries might soon be made on the lunar surface, were such minute observations as those now suggested to be continued for a series of years, which might afford sensible and demonstrative evidence of the moon's being a habitable world. But before attention to such objects become general, and the number of astronomical observers be increased far beyond what it is at present, such discoveries can scarcely be expected.

I shall only remark farther on this head, that several discoveries have been made by accidentally directing a telescope to certain parts of the heavens. It is well known that Miss Herschell, while amusing herself in looking at the heavens through Sir William Herschell's telescope, discovered at different times a variety of comets, which might otherwise have passed unnoticed by the astronomical world; and several of the new planets which have been discovered within the last 50 or 60 years, were detected when the discoverers were employed making observations with a different object in view. The splendid comet which appeared in our hemisphere in 1811, was first discovered in this country by a sawyer,* who, with a reflecting

* The name of this gentleman is Mr. Veitch, and I believe he resides in the neighbourhood of Kelso.

vens.

telescope of his own construction, and from his sawpit as an observatory, descried that celestial visitant before it had been noticed by any other astronomer in North Britain. The author of this work detected this comet a day or two afterwards, before he had been informed of the discovery, while he was taking a random sweep over the northern region of the heaHe had directed his telescope to a certain star in the neighbourhood of Ursa Major, and immediately afterwards, taking a general sweep upwards and downwards, and to the east and west, an uncommon object appeared in the field of view, which, after a little inspection, was perceived to be a comet, and he naturally concluded that he had made the first discovery, till the newspapers afterwards informed him that it had been detected a day or two before. It was while Sir W. Herschel was inspecting some small stars near the foot of Castor, with a different object in view, that he discovered the planet which bears his name, and which he at first took for a comet. It had been seen thirty years before, but for want of numerous observers to mark its motions, it had been marked in catalogues as a fixed star. It was while Mr. Harding of Lilienthal, near Bremen, was forming an atlas of the stars so far as the eighth magnitude, that, on the 1st September 1804, he discovered in the constellation Pisces the planet Juno, one of the four asteroids situated between the orbits of Mars and Jupiter.

If, therefore, instead of a few individuals occasionally engaged in surveying celestial phenomena, and chiefly confined to a small portion of Europe,were thousands and ten thousands of telescopes daily directed to the sky from every region of the earth, and were distinct portions of the heavens allotted to

distinct classes of observers, as the object of their more immediate research, every portion of that vast concave, with the numerous globes which roll within its wide circumference, as far as human vision assisted by art can penetrate, would ere long be thoroughly explored, and its hidden worlds disclosed to view. No comet could pass within the orbit of Jupiter without being detected,—the undiscovered planets belonging to our system, if any still remain, would be brought to view,-the periodical changes on the surfaces and in the atmospheres of the planets already discovered, with all their diversified phenomena, would be more accurately ascertained and delineated, -the path of the solar system in absolute space, the velocity of its motion, the distant centre about which it revolves, and the centre of gravity of the Nebula to which it belongs, might be determined,―the changes and revolutions that are taking place among the fixed stars, the undiscovered strata of Nebula,-the old systems that are going into decay,-the new creations that may be emerging into existence, and many other sublime objects which at present lie concealed in the unexplored regions of space, might be brought within the range of human contemplation, and astronomy, the sublimest of all the sciences, approximate towards perfection.

For making the observations now supposed, a profound knowledge of the physical and mathematical principles of astronomy is not absolutely necessary. All the qualifications essentially requisite are,-a general knowledge of the elements of the science, of the celestial phenomena which have already been explored, and of the method of determining the right ascension and declination of any observed phenomenon,-qualifications, which every person of common understanding can easily acquire.

I might next have illustrated the general position laid down in the beginning of this section from the science of chemistry. This science, having for its object to ascertain the ingredients that enter into the composition of bodies, the nature of those ingredients, the manner in which they combine, and the properties resulting from their combination; or, in other words, an analytical examination of the material world, and the principles which concur to produce its diversified phenomena; it is apparent, at first view, that an immense number and variety of experiments are indispensably requisite for accomplishing such objects; and, consequently, that its progress towards perfection cannot be accelerated, unless multitudes of experimenters concur in observing the phenomena of nature, and the processes of the arts, in instituting analytical experiments, and in prosecuting every inquiry which has a tendency to promote its improvement. It is chiefly in consequence of the increased number of its cultivators that this science has risen to the distinguished rank it now holds among the useful departments of human knowledge, and that so many brilliant discoveries have rewarded the investigations of its votaries. Wrenched from the grasp of empirics and alchymists, and no longer confined to the paltry object of searching for the philosopher's stone, it extends its range over every object in the material world, and sheds its influence over all the other departments of physical science; and as its votaries increase in numbers and in perseverance, it will doubtless bring to light scenes and discoveries still more interesting and brilliant than those which have hitherto been disclosed.-Illustrations of the same description might also have been taken from optics, electricity, magnetism, galvanism, pneumatics, and other

departments of natural science; but having protracted this section to a disproportionate length, the instances already stated will, I presume, be sufficient to prove the truth of the position," that a general diffusion of knowledge would have a powerful influence on the progress of science."

From the few hints now given, and from many others that might have been suggested, had my limits permitted, it will appear, that much still remains to be accomplished till any science, even those which are farthest advanced, arrive at perfection. The reason is obvious; the scene of universal nature has never yet been thoroughly surveyed, and never will be, till the eyes and the intellects of millions be fixed in the contemplation of its multifarious and diversified objects, and relations. Till the universe, in all its aspects, so far as it lies within the range of human inspection, bẹ more particularly explored, clouds and darkness will continue to rest on many interesting departments of knowledge, and many of our most specious theories in the sciences must be considered as reposing on slender and unstable foundations. Prior to the introduction of the inductive method of philosophizing, men of science were extremely prone to the framing of hypotheses, before they had attentively surveyed and collected the requisite facts, and when only a few scattered fragments of nature were present to their view. Theory was reared upon theory, and system upon system; each of them obtained its admirers and its period of applause, but, in consequence of modern researches, they have now passed away like a dream or a vision of the night. The crystalline spheres with which Ptolemy had enclosed the heavens are now dashed to pieces; the vortices of Des Cartes have long since ceased their whirling; the terraqueous globe