of fourteen feet, with a long screw, moved either by hand or by a clock, with a rate variable with the declination. The hour angle will, in such cases, be obtained by another circle and level. The other pier carries the galleries for the observers, which, for fear of producing tremor, Lord Rosse was unwilling to attach to the tube. The galleries will consist of three stages, with some help from ladders, each stage being pushed forward in succession from the top of the piers.

This immense mass of matter weighing about twelve tons, requires to be counterpoised, and Lord Rosse's arrangements for this purpose are most ingeniously contrived. When in the zenith, the tendency of the telescope to fall is nothing, but on each side it gradually increases, and is a maximum at the horizon. The first plan of a counterpoise was this. A chain attached to the upper end of the tube passes over a pulley, and carries the counterpoise which rolls on a curved railway, which can be so formed that the telescope may be in equilibrium through its whole range. The arrangements for this contrivance are already made, but Lord Rosse intends to try a much simpler method, in which the weight, in place of rolling, is kept attached to a fixed point by a guy, so that when the tube is low the weight acts to great mechanical advantage, and when high with less advantage.

Such is a brief description of the noble telescope completed by the Earl of Rosse-a telescope gigantic even among the giant instruments which preceded it. In order to form an idea of its effective magnitude, we must compare it with other instruments, as in the following table, which contains the number of square inches in each speculum, on the supposition that they were square in place of round.

In glancing over the preceding table, and marking the rapid strides of the reflecting telescope, it is impossible to restrain the mind from anticipating still grander achievements. If Sir William Herschel made such a start a-head of his predecessors, and if Lord Rosse has taken such a flight beyond his first high position, may we not expect that he, or at least his successor in discovery, will execute the two instruments which we have placed below his own? But it is not merely in the course which has been already pursued, that we are to look for an extension of our astronomical knowledge. We have yet to try what can be effected by specula of moderate apertures and extremely long foci, in which the spherical aberration will almost disappear, for there can be no doubt that a true spherical figure can be more perfectly attained than a parabolic one. The value of fixed telescopes, too, kept in dry vaults of uniform temperature, into which the rays are to be admitted by plain reflectors, remains to be tried; and we venture to propose as practicable, the combination of two or more specula in a single telescope. If a six feet spherical speculum has its circular diaphragm of six feet converted into two of three feet each, the effect will be exactly the same as that produced by the combinations of two three feet spherical reflectors. Lord Rosse may, therefore, by the fine adjustments which he has already executed, unite his two six feet mirrors, and thus produce a speculum with a proportional area of 10368 square inches, exceeding in surface our hypothetical speculum of 83 feet!

But our views must not be confined to the principle of reflexion. The Achromatic Telescope may yet take the start of reflectors, as it once did; and when we consider the successive steps of Lord Rosse's progress, we can scarcely doubt, that with his hands so skilful, and his head so stored with the chemistry of fusion, and the physics of annealing, lenses of flint and crown glass may yet be executed of gigantic magnitude, or even meniscuses of plate glass to hold gallons of fluid for the construction of aplanatic object-glasses.

In cherishing these high expectations, we have not forgotten that the state of our atmosphere must put some limit to the magnifying power of our telescopes. In our variable climate, indeed, the vapours, and local changes of temperature, and consequent inequalities of refraction, offer various obstructions to the extension of astronomical discovery. But we must meet the difficulty in the only way in which it can be met. The astronomer cannot command a thunder-storm to cleanse the atmosphere, and he must therefore undertake a pilgrimage to better climates-to Egypt or to India, in search of a purer and more homogeneous medium;- -or even to the flanks of the Himalaya and the Andes,

VOL. II. NO. III.

that he may erect his watch-tower above the grosser regions of the atmosphere. In some of those brief yet lucid intervals which precede or follow rain, when the remotest objects present themselves in sharp outline and minute detail, discoveries of the highest value might be grasped by the lynx-eyed astronomer. The resolution of a nebula-the bisection of a double star-the details of a planet's ring-the evanescent markings on its disc-or perhaps the display of some of the dark worlds of Bessel-might be the revelations of a moment, and would amply repay the transportation of a huge telescope to the shoulder or to the summit of a lofty mountain.

In looking back upon what the telescope has accomplished;—in reckoning the thousands of celestial bodies which have been detected and surveyed;-in reflecting on the vast depths of ether which have been sounded, and on the extensive fields of sidereal matter out of which worlds and systems of worlds are forming, and to be formed-can we doubt it to be the Divine plan that man shall yet discover the whole scheme of the visible universe, and that it is his individual duty, as well as the high prerogative of his order to expound its mysteries, and to develop its laws? Over the invisible world he has received no commission to reign, and into its secrets he has no authority to pry. It is over the material and the visible that he has to sway the intellectual sceptreit is among the structures of organic and inorganic life that his functions of combination and analysis are to be chiefly exercised. Nor is this a task unworthy of his genius, or unconnected with his destiny. Placed upon a globe already formed, and constituting part of a system already complete, he can scarcely trace either in the solid masses around him, or in the forms and movements of the planets, any of those secondary causes by which these bodies have been shaped and launched on their journey. But in the distant heavens, where creation seems to be ever active, where vast distance gives us the vision of huge magnitudes, and where extended operations are actually going on, we may study the cosmogony of our own system, and mark, even during the brief span of human life, the formation of a planet in the consolidation of the nebulous mass which surrounds it.

Such is the knowledge which man has yet to acquire-such the lesson which he has to teach his species. How much to be prized is the intellectual faculty by which such a work is to be performed;-how wonderful the process by which the human brain, in its casket of bone, can alone establish such remote and transcendental truths. A soul so capacious, and ordained for such an enterprise, cannot be otherwise than immortal.

But even when all these mysteries shall be revealed, the mind will still wrestle with eager curiosity to learn the final destiny of

such glorious creations. The past and the present furnish some grounds of anticipation. Revelation throws in some faint touches of its light; but it is in the indications of science chiefly-in the results of mechanical laws-that we are likely to find any sure elements for our judgment. In the creations around and near us all is change and decomposition. The solid globe, once incandescent, and scarcely cooled, has been the theatre of recurring convulsions, by which every thing has been destroyed, and after which every thing has been renewed. Animal life in its varied organizations has perished, and written its epitaph upon imperishable monuments. Man too, though never extinct as a race, returns one by one to his clay, and his intellectual functions are perpetuated in the reproduction of his fellow. In the solar system, we see fragments of planets-asteroids, as they have been called-occupying, in almost interlacing orbits, the place of a larger body; and in the direction and amount of the annual and diurnal motions of the primary and secondary planets, we recognize the result of a grand creative movement, by which the sun, with its widely extended atmosphere, or a revolving atmosphere itself, has cast off, by successive throes, the various bodies of the system, at first circling in gaseous zones, but subsequently contracted into planets and a sun.

This system, so wonderfully formed, is again enchained with another more distant by an assemblage of comets—a class of bodies which doubtless carry on some reciprocal intercourse for the benefit of both. Composed of nebulous matter, they may yet be consolidated into habitable globes; and resembling in aspect the vast nebula which fill the sidereal spaces, and forming a part of our own system, they countenance the theory, that the nebulæ which the telescope cannot resolve may be the pabulum out of which heat and motion are to form new systems, where planets, thrown off from a central nucleus, will form new abodes of life and intelligence.

But while all the phenomena in the heavens indicate a law of progressive creation, in which revolving matter is distributed into suns and planets, there are indications in our own system, that a period has been assigned for its duration, which, sooner or later, it must reach. The medium which fills universal spacewhether it be a luminiferous ether, or arise from the indefinite expansion of planetary atmospheres-must retard the bodies which move in it, even though it were 360,000 millions of times more rare than atmospheric air; and, with its time of revolution gradually shortening, the satellite must return to its planet, the planet to its sun, and the sun to its primeval nebula. The fate of our system, thus deduced from mechanical laws, must be the fate of all others. Motion cannot be perpetuated in a resist

ing medium; and where there exist disturbing forces, there must be primarily derangement, and ultimately ruin. From the great central mass, heat may again be summoned to exhale nebulous matter;-chemical forces may again produce motion, and motion may again generate systems; but-as in the recurring catastrophes which have desolated our earth, the great First Cause must preside at the dawn of each cosmical cycle-and, as in the animal races which were successively reproduced, new celestial creations, of a nobler form of beauty, and of a higher order of permanence, may yet appear in the sidereal universe. "Behold, I create new heavens and a new earth, and the former shall not be remembered." "The new heavens and the new earth shall remain before me." "Let us look, then, according to his promise, for the new heavens and the new earth, wherein dwelleth righteousness."

The Public and Private Life of Lord Chancellor Eldon, with Selections from his Correspondence. By HORACE TWISS, Esq. Three vols., 8vo. London, 1844.

In an age which, unlike that in which Tacitus wrote, is little liable to the charge of being "incuriosa suorum," this is one of the best biographies, in a literary point of view, that has lately appeared. To write a good life, if not the highest effort of narrative talent, must be one of the most difficult, if we are to judge by the frequency of failure. The incidents, indeed, in the lives of ordinary men, which are of the greatest personal importance to themselves, seldom have enough of point or peculiarity to raise interest in the mind of the general reader; and the biography of many a man whose days have been spent in stirring scenes, and who may have contributed to the great events of his age, may yet, when in the hands of an historian, be little more readable than a merchant's day-book.

There is, however, one secret of story-telling, of which, when the subject admits of it, the biographer may avail himself with great effect. It has been very truly said, that if all the little events of any man's life were narrated from day to day, they would in the end make an interesting book. Perhaps this may arise from the interest we always take in the development of unforeseen results from any regular progress of events; or perhaps it is a branch of that implanted curiosity which creates in all male and female hearts so great a sympathy in their neighbours' concerns, and makes a dinner party or a wedding next