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nundred years) in which the polar and equatorial diameters of this planet can be measured, and their difference, if any, ascertained, so as to determine whether its figure, like that of the earth and several other planets, be spheroidal. But as this planet may not happen for a series of years to be in the precise position for such an observation, the attempt to determine the points now stated, even when the planet happens to be placed in the requisite circumstances, would, in all probability, fail, if a number of observers at the same time, in different places, were not engaged in the observation; on account of the uncertainty of enjoying a serene sky at one particular place, during the moments when the observation behooved to be made. Whereas, by a multitude of observations in different places, the object in view could not fail of being determined. The disputes respecting the period of rotation of this planet (whether it be 23 hours 20 minutes, or 24 days 8 hours) might also be settled, were a number of persons to observe its surface with equatorial telescopes in the daytime; particularly in those southern climes where the air is serene, and the sky exhibits a deep azure, where, in all probability, spots would be discovered, which could be traced in their motions for successive periods of twelve hours or more, which would determine to a certainty the point in question. The following figure and explanation will perhaps tend to show the reason of the dispute which has arisen in reference to this point. Let A represent a spot on the surface of Venus.

As this planet is seen, by the naked eye, only in the morning a little before sun-rise, or in the evening a short time after sun-set—the motion of the spot cannot be traced above an nour or two in succession; and, consequently, during that time, its progressive motion is almost imperceptible. Suppose the observation to have been made in the evening, after sun-set, the

next observation cannot be made till about the same time, on the following evening, when it is found that the spot has moved from A to B. But it is still uncertain whether the spot has only moved from A to B, since the last observation, or has finished a complete revolution, and moved the distance A B as part of another revolution round the axis of the planet. This point can only be ascertained by tracing the motion of the spot without interruption for 10, 12, or 14 hours, when, if the rotation is performed in 23 hours, the motion of the spot could be traced without interruption across the whole disk of the planet. But such an observation could only be made in the day-time, in a serene sky, and by means of equatorial instruments, and by numbers of observers in different places, where the attention is directed to the same object. But the limits to which I am confined, in throwing out these cursory hints, prevent me from entering into minute details. In regard to comets, it is scarcely necessary to remark, that were the number of those whose attention is directed to a survey of the heavens considerably increased, many of those eccentric bodies, which pass and repass within the orbits of the planets without being perceived, could not fail of being detected. Were multitudes of such persons engaged in exploring the celestial regions, on opposite sides of the globe, those comets which pass within the limits of our view, and which are above our horizon only in the day-time, and consequently invisible, would be detected, during the night, by our antipodes in the opposite regions of the globe. . By this means the number of those bodies belonging to our system, the diversified phenomena they present, the form of their trajectories, the periods of their revolutions, the nature of their tails, and their ultimate destination, might be more accurately determined. With respect to the Jired stars, particularly those termed variable stars, the results of a multitude of observations made by different persons, might lead us to determine, whether those changes in brightness which they undergo, arise from the transits of 'arge planets revolving around them, and thus furnish direct evidence of their being the centres of systems analogous to our own, or whether they be occasioned by large spots which periodically interpose between our sight, and then disappear in the course of their rotation-or whether the distance of such stars be changed by their revolving in a long narrow ellipse, whose transverse axis is situated nearly in our line of vsion. In the several instances now stated, an immense variety of successive observations, by numerous observers at different stations, are requisite to accomplish the ends in view; but the limits of this section prevent me from entering into those details requisite for rendering the hints now suggested perspicuous to those who

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nave not devoted their attention to this subject.

The Moon being the nearest celestial body to the earth, it might have been expected that the variety of scenery on her surface, and even some parts of her physical constitution, might have been ascertained an I do lineated. Yet all that has hitnerto been discovered wih certainty in relation to this body is, that her surface is sinkingly diversified with mountains and vall with vast caverns or hollows surrounded with mountainous ridges, and with several elevated peaks, which rise, like a sugar loaf, from the middle of the plains. We have no accurate delineation of the lunar scenery, as exhibited in the various stages of the moon's increase and decrease, except those which have been published by Hevelius and Schroeter, which have never been translated into our language, and, consequently, are very little known. Most of our English books on astronomy contain nothing more than a paltry and inaccurate view of the ful moon, which has been copied by one eng-aver from another, without any improvements, ever since the days of Ricciolus, and long before the telescope was brought to its present state of inprovement. It is not from a telescopic view of the full moon that any specific deductions can be made respecting the appearance and arrangement of her diversified scenery; but from long-continued observations of her surface about the period of the quadratures, and at the times when she assumes a crescent or a gibbous phase; for it is only at such times that the shadows of her cavities and mountain-ridges can be distinctly perceived. As there is none of the celestial bodies whose constitution and scenery we have so excellent an opportunity of inspecting, had we a sufficient number of astronomical observers, furnished with good telescopes, the surface of this globe might be almost as accurately delineated as that of the carth, and the most prominent changes that take place on its surface plainly detected. In order to bring to light the minute parts of its scenery, it would only be requisite to distribute the entire surface of this luminary among a hundred or a thousand observers, allotting to each one or more spots as the particular object of his attention, with the understanding, that he is to inspect them with care through every variety of shade they may exhibit, and during the different stages of the moon's increase and decrease, and delineate the different aspects they may present. When we consider that, by means of a telescope which magnifies 300 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 night 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 ob. Jects 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, thet several discoverics 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 telescope of his own construction, and from his saw pit 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 heavens. He 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. Herschell 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 phe

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

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nomena, and chiefly confined to a small portion pf 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, he 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 chymistry. 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 accecrated, 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 humau 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 multisarious and diversified objects and relations. Till the universe, in all its aspects, so far as it lies within the range of human inspection, be 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 slendel 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 which Tycho had fixed in the centre of the universe is now set in rapid motion through the heavens, in company with the planetary orbs; and the abyss of water with which Burnet had filled the internal cavity of the earth is now converted into a mass denser than the solid rock. The Terra Austraus Incognito, which served as a prop to certain theories, has completely evanished, and is now transformed into a dreary mass of water and ice. The subtle ether, which formerly accounted for so many phenomena, is now evaporated into electricity and heat. Whiston's idea of the cornetary origin of our globe, and Buffon's fancy of the earth's being a splinter struck from the body of the sun, are fast sinking into oblivion; and such will be the fate of every theory, however specious, which is not founded on the broad basis of inductive evidence. Even in the present day, there is still too great a propensity to generalize, without submitting to the trouble of observing phenomena, and noting their various modifications and attendant circumstances. The human mind is impatient, and attemp's to reach the goal by the shortest and most rapid course, while observation and experiment are tedious and slow. Instead of surveying the material world with his own eyes, and investigating, by observation and experiment, its principles and laws, the man of genius frequently shuts himself up in his closet, and from a few scattered fragments of nature, constructs, in his imagination, a splendid theory, which makes a noise and a blaze for a little, iike an unsubstantial meteor, and then evanishes into air. The system of nature, though directed in its general movements by a few simple laws, is too grand and extensive, and too complex in many of its parts, to be grasped by a few individuals, after a cursory survey; and, therefore, to attempt to comprehend its multisarious revolutions, phenomena and objects within the range of theories founded on a partial view of some of its detached parts, is not only an evidence of presumption and folly, but tends to damp our ardour in prosecuting the only sure path which leads to discovery, and to frustrate what appears to be one of the designs of the Creator, namely, to grant to the intelligent inhabitants of our globe a gradual display of his stupendous plans in the universe as the reward of their incessant and unwearied contemplation of his wondrous works. Were the period arrived (and of its arrival I entertain no doubt, from the present movements of the human mind) when the majority of mankind shall devote a portion of their time and attention to the purposes of science, and to the con emplation of nature—then the different tastes of individuals, and the various situations in which they may be placed, would lead them to cultivate more particularly the science most tongenial to neir minds; and were distinct

departments of the same science marked out for distinct classes of individuals, as the more immediate field of their investigation, on the principle of the division of labour, every leading principle and fact in relation to that science would soon be detected and illustrated in all its practical bearings. Even as matters presently stand, were the whole literary and scientific world to form itself into one great republic, and to allot the several branches of every department of knowledge to the different classes of such a community, according to their respective tastes and pursuits, as the object of their more particular attention, it might be followed by many interesting results, and important discoveries and improvements. But we live in too early a period in the history of science to expect a general interest to be taken in such objects; we are but just emerging from the gloom of ignorance and superstition; the great body of mankind still suffer their faculties to lie in a state of languor and inactivity, and those who are more vigorous and alert are too much engrossed in commercial speculations, in grasping at power and opulence, and in the indulgence of sensual gratifications, to think of attending to the interests of science and the progress of the human mind. Much, however, might be accomplished in this respect, with ease and pleasure, by various classes of society, and without interfering with their ordinary avocations, were their minds inclined and their attention directed to such pursuits. Sailors, in crossing the Atlantic, the Pacific, and the Indian oceans, have frequently excellent opportunities of observing the phenomena of the waters, the atmosphere, and the heavens, peculiar to the climates through which they pass; and were the facts presented to their view observed with care, classified, and recorded, they might, in many instances, contribute to the advancement of science. But thousands of such persons can sail twice “from Indus to the frozen pole, as ignorant as their log, and as stubborn as their compass,” without importing one intellectual acquisition. The observations made during a single voyage across the Atlantic, by a single observer, M. Humboldt, on the aspect of the Antarctic region of the heavens—the peculiar azure of the African sky—the luminous meteors of the almosphere—the tides, the currents, and the different colours of the ocer., and other phenomena which happened to present themselves to his view—are of more value to the scientific world than the observations of ten thousands of other beings who, for a series of years, have traversed the same regions. Yet these possessed, on an average, the same sentient organs, the same intellectual powers, though somewhat differently modified and directed, the same natural capacities for observation as this distinguished philosopher, which required only an impulse to be given in a certain direction, in order to accomplish the same ends. And was Humboldt more burdened and perplexed, or did he feel less cornfortable and happy than his ignorant and grovelling associates in the ship that wasted them across the ocean No. He felt emotions of delight and intellectual enjoyments to which they were utter strangers. While they were lolling on their hammocks, or loitering upon deck, viewing every object with a “brute unconscious gaze,’ and finding no enjoyment but in a glass of grog, —a train of interesting reflections, having a relation to the past, the present, and the future, passed through the mind of this philosopher. He felt those exquisite emotions which arise

from perception of the beautiful and the sub

lime; he looked forward to the advancement of natural science as the result of his observations, and beheld a display of the wisdom and grandeur of the Almighty in the diversified scenes through which he passed. Such observations and mental employments as those to which I allude, so far from distracting the mind, and unfitting it for the performance of official duties, would tend to prevent that languor and ennui which result from mental inactivity, and would afford a source of intellectual enjoyment amidst the uniformity of scene, which is frequently presented in the midst of the ocean. From the whole that has been now stated on this subject, it appears, that in order to make science advance with accelerated steps, and to multiply the sources of mental enjoyment, we have only to set the machinery of the human mind (at present in a quiescent state) in motion, and to direct its movements to those objects which are congenial to its native dignity and its high destination. The capacity of the bulk of mankind for learning mechanical employments, and for contriving and executing plans of human destruction, proves that they are competent to make all the researches requisite for the improvement of science. The same mental energies now exerted in mechanical labour and in the arts of mischief, if properly directed, and acting in unison, and accompanied with a spirit of perseverance, would accomplish many grand and beneficent effects, in relation both to the physical and moral world, and would amply compensate the occasional want of extraordinary degrees of mental vigour. Were only a hundred millions of eyes and of intellects, (or the tenth part of the population of our globe) occasionally fixed on all the diversified aspects, motions and relations of universal nature, it could not fail of being followed by the most noble and interesting results, not only in relation to science, but to social and moral order, and to the general melioration of mankind. Were this supposition realized, our travellers, merchants, and mariners, along with the pro

duce of soreign lands, might regularly import, without the least injury to their commercial interests, interesting facts, both physical and moral, scientific observations, chymical experiments, and various other fragments of useful information for rearing the Temple of Science, and extending the boundaries of human knowledge.

SECTION IV.

on trie Pleasura es and Enzoynients coroin Ected with the pursuits or science.

MAN is a compound being; his nature con sists of two essential parts, body and mino Each of these parts of the human constitutio. has its peculiar uses, and is susceptible of peculiar gratifications. The body is furnished with external senses, which are both the sources of pleasure and the inlets of knowledge, and the Creator has furnished the universe with objects fitted for their exercise and gratification. While these pleasures are directed by the dictates of reason, und confined within the limits prescribed by the Divine law, they are so far from being unlawful, that in the enjoyment of them we fulfil one of the purposes for which our Creator brought us into existence. But the pursuit of sensitive pleasures is not the ultimate end of our being; we enjoy such gratifications in common with the inferior animals; and in so far as we rest in them as our chief good, we pour contempt on our intellectual nature, and degrade ourselves nearly to the level of the Leasts that perish.

Man is endowed with intellectual powers, as well as with organs of sensation,-with faculties of a higher order, and which admit of more varied and sublime gratifications than those which the senses can produce. By these faculties we are chiefly distinguished from the lower orders of animated existence; in the proper exercise and direction of them, we experience the highest and most refined enjoyments of which our nature is susceptible, and are gradually prepared for the employments of that immortal existence to which we are destined. The corporeal senses were bestowed chiefly in subserviency to the powers of intellect, and to supply materials for thought and contemplation; and the pleasures peculiar to our intellectual nature, rise as high above mere sensitive enjoyments, as the rank of man stands in the scale of existence, above that of the fowls of the air, or the beasts of the forest. Such pleasures are pure and refined; they are congenial to the character of a rational being; they are more permanent than mere sensitive enjoyments' they can be enjoyed when worldly comforts are

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