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his mind, led him to expatiate in a field | kind was, that of all the stars which are which was vast and unbounded, as well as singly visible, about one in thirty is underunexplored.

going observable change. “ The catalogue of Messier, communicated to

The powerful instruments at Slough fully the academy in 1771, and inserted, with some confirmed the opinion that the stars are additions, in the Connaissance des Temps' of not, in the ordinary sense of the word, 1783, contained 68 nebulæ, which, together with magnified; on the contrary, the more pow28 added by Lacaille, made up a lotal of 96. ersul the telescope, the less the apparent This branch of science took a rapid flight, how- diameter of the star. The efficacy of the ever, as soon as Herschel applied to it his pow. telescope in stripping the star of its crown erful instruments, his rare penetration and unconquerable perseverance. "lo 1786 he publish- of splendor to which it owes it apparent ed, in the Philosophical Transactions, a cata- magnitude, more than counterbalancing logue of a thousand nebulæ or clusters of stars. the increase of the real disk. The stars in Three years later, there appeared, 10 the aston- the heavens thus resemble many of our ishment of practical astronomers, a second cata-stars on earth, from which, if we take away logue froin him, quite as extensive as the first; the flash and glitter, it will be found hard and that again was followed, in 1802, by a third catalogue of 500 nebulæ. Two thousand five to raise their solid merits by any magnifyhundred nebulæ! such was the contingent fup- ing power to an appreciable quantity. But plied by Herschel to a branch of astronomy to speak more precisely: Herschel ascerwhich had been hardly touched before him. At tained that the apparent diameters of the the same time, the extensiveness of this work stars are really increased by telescopes, was its least merit.”

though not in the same proportion as the In surveying the astronomical labors or magnifying powers; a double power showHerschel, our object is not so much to in- ing a star with less than double its previous sist on their number, variety, and combined his instruments, and his scrupulous acco

of value, as to show that from the boldness of his genius, his assiduity, and the accura- below the measures previously assigned to

racy,

reduced these apparent diameters far cy of his observations, he took his station

them. at once among the most eminent astrono- Sirius to be four minutes; Tycho Brahe

Kepler believed the diameter of He turned his attention to the supposed that stars of the first magnitude changes taking place in the sidereal bea- have, in general, a diameter of two minutes. vens, and the result was, a catalogue of With the improvement of instruments these stars, classed according to their intensities, measures, or rather estimates, were conso numerous and exact as to suffice for the inually reduced, till at length Cassini asbasis of all future labors in that department. signed to Sirius a diameter of five seconds. As to his observations of changing stars, it Herschel, however, employing the highest does not comport with our plan or limits magnifying powers, found that the apparent to enter far inio such details. The seventh diameter of the chief star in the Lyre is pleiad is not the best authenticated instance about the third of a second ; and that of of an extinguished star. The journals of Arcturus, two-tenths of a second, wbich he the astronomer of Slough could furnish several other examples, but the following the value of these observations may be

supposes to be double of the true diameter. will suffice.

collected from the following remarks of M. • The star numbered the 55th of Hercules, Arago:placed in the neck of the figure, has been insert “It is of the greatest importance to ascertain ed in Flamisteed's catalogue as a star of the fifth the share which illusions of vision bave in the magnitude. The 10th of October, 1781, Her- magnitude of the diameter under which we see schel saw it distinctly, and noted that it was the stars, whether with the naked eye or with red; the 11th of April, 1782, he perceived it telescopes. Suppose the disks, seen with the again and marked it in his journal as an ordina- naked eye to be the real disks, then it will follow ry star. Nine years later it was not to be found, that some stars will be 9000 million of leagues though repeatedly looked for. So the 55th of in diameter. In fact, it is proved, by observaHercules has disappeared."

tions of parallax, that, at the distance of the

nearest stars, a diameter of one second would If old stars perish, it is equally certain answer to at least 38 millions of leagues; consethat new stars occasionally appear. Her- quently the diameter of Sirius, according to schel watched closely, also, the periodical Kepler?s measure of that star, would be at least stars, which undergo a change of bright. Gassendi and Cassini, though much reduced, ness at regular intervals of time, and he

would still ve to some of the stars diameters furnished lists of the colored stars. The of :380 millions of leagues. The observations of general result of his observations of this. Herschel give us, for the diameter of Arcturus,

mers.

four millions of leagues, which is still eleven the British Association at its last meeting, times the diameter of our sun.

it will be here sufficient to state briefly,

that he found the parallax of a small star, The earth, in its annual revolution, moves in the constellation of the Swan, to be in an orbit having a diameter of 76 millions about the third of a second, or more strictly of leagues. Now it must strike every one 04. 31. This parallax corresponds to a that a star ought to appear in different po- distance from the earth, exceeding 600,000 sitions, when viewed from two points 76 times the distance from the earth to the millions of leagues asunder. If when the sun; and which, light, with its velocity of earth is in the southern part of its orbit, a 77,000 leagues in the second, could not pass star be observed near the North Pole, then, over in less than ten years. six months after, when the earth is 76 mil. Herschel's labors in seeking the parallax lions of leagues further north, that star of the fixed stars were not wholly thrown ought to appear higher in the heavens, un away. Though he did not find what he less the diameter of the earth's orbit be as sought, he made, incidentally, discoveries nothing compared to the distance of the no less memorable and quite unexpected. star. The angle, nevertheless, indicating Movements of the stars had been previously such a change of place in a star (and which detected, and For lle had ventured to is called parallax), was in Herschel's time suggest that our sun also moved. thought inappreciable, being too minute to

“So far," observes M. Arago, “astronomers be safely disentangled from the inevitable remained within the domain of conjecture, and errors of observation. No one could show of mere probability. Herschel went beyond that the parallax of any fixed star equalled these limits; he demonstrated that the sun aca single second; whence it necessarily tually moves; that in this respect, too, the imfollowed, that the nearest star was, at leasi, mense, dazzling central body of our system, eight millions of millions of leagues from must be counted as a star; that the apparently the earth. He, however, made a grand step

inextricable irregularities of the sidereal motions, towards the decision of this interesting the solar systein; and finally, that the point of

are partly derived from the change of place of question. He proposed that instead of ob space towards which our system is constantly serving the absolute position of a single moving, is in the constellation of Hercules. These star, we should fix our attention on a double are magnificent results. The discovery of the star; for if the two stars, which were ap- proper movement of our system will always be parently brought together by an effect of reckoned among Herschel's chief titles to re

nown.” projection, happened to be at very different distances from the earth, then, having dif- But he went further than this: he showed ferent parallaxes, they would change place not only that the sun is a star, and holds with respect to each other, a motion which, a place in the sidereal movements, but also however minute, might be observed with that the stars are many of them suns and ease and certainty. It does not detract the centres of systems. He showed in from the merit of this suggestion that the fact, that there are groups of stars not same method had before occurred to the formed accidentally nor associated by perminds of Galileo and Gregory. Herschel, spective, but connected together and formwho was strong in original genius though ing true systems. He pointed out the fact, not in erudition, certainly did not borrow that there are stars revolving round other the hint from his precursors; and with him stars in less time than is required by Uranus moreover it was no hint, but a well-develop- to complete its circuit of the sun. And ed method ; and to facilitate the proceed these discoveries did not proceed from a ing which he recommended, he published hot theorist possessing practical dexterity catalogues of the double stars which seemed enough to confirm his views; they were best adapted for the purpose.

the discoveries of one whose work was To choose the proper star for observa- always of the most solid kind ; a consumtions of parallax, is, in a great measure, a mate observer; whose enthusiasm stimumatter of good fortune. Herschel did not lated but never overruled his sagacity and make the discovery, though he showed the perseverance. path to it; but his method has recently had “There is no branch of astronomy which complete success in the hands of M. Bessel Herschel might more justly have called his of Königsberg, to whom belongs the glory own, than that which treats of clustered of first demonstrating the exact value of an stars and luminous nebulæ. Besides the element which goes far to determine the wide latitude which he found in that remote dimensions of the universe. As the details field of speculation for the exercise of a of M. Bessel's discovery were laid before daring sagacity, he enjoyed, in the posses

Vol. II. No. IV. 36

sion of the most powerful instruments, ad - this science owes more to his practical vantages for the study of the smaller stars skill than to his happy conjectures. He which had never been enjoyed before. was the first who really gauged (to use his This superiority may be best estimated own expression) the heavens. The stars from the fact, that in a small luminous visible in the heavens on a clear night are spot or nebula, in which before him no eye about 5000 in number. Now Herschel, by had ever discerned a star, he was able to reckoning the stars in given spaces where count 14,000 stars! We have seen that he the stellar light is equally diffused, ascerrapidly raised the number of observed nebu- tained that within the space of five degrees lous stars from 96 to 2500. The general in the Milky-way there are at least 331,000 result of his speculations on these pheno- stars. He also clearly established by thoumena is thus explained by his biographer : sands of observations, that the whiteness

“On the grounds of probability no reasonable of the Milky way, is due not to these mulperson will refuse to adopt the views of Herschel, titudes of discernible stars, but to gatherand he will remain convinced, that there really ings of stars too small to be distinguished. exist brilliant stars surrounded by atmospheres, The crude luminous matter or raw material luminous of themselves; and the supposition here plays a subordinate part among bosts that these almospheres, becoming condensed of stars. The Milky-way, though to a unite with or are absorbed in the central stars so careless observer it may appear uniformly as to increase their splendor, will then appear very plausible. The recollection of the Zodiacal luminous, will yet be found by an experilight--that immense luminous zone surrounding enced eye to be divided into separate the equator of our sun, and extending even as far groups, and this grouping of the light was as the orbit of Venus-will then strike the mind, considered by Herschel as progressive. M. as a new feature of resemblance between our sun Arago shares his belief, and exclaims, and certain stars: and the nebulæ which have is

Every thing justifies the opinion of the in their centre condensations of light more or less decided, will present themselves to the

illustrious astronomer. In the course of imagination as the first outlines of stars, or as a ages, the clustering power (this is Herstate of luminous matter intermediate between schel's expression) will inevitably bring the uniformly diffused nebulæ and the nebulous about the disruption, subdivision, and sepstars properly so called. These speculations of aration of the Milky-way. Herschel conduct to nothing less than the sup- The sun also shared the vigilant attenposition that the formation of new stars is con- tion of the Astronomer of Slough : and tinually going on, and that we witness the slow, here again his opinions have made such an progressive creation of new suns."

impression on the learned world as can only For many years Herschel held that all be effected by those issuing from a master the nebulæ are composed of stars. He spirit. According to bim, the light of the subsequently modified this opinion, how. sun does not proceed from the solid nuever, and admitted that there are some ne. cleus of that body, but from a cloud-like bulæ which are not of a starry nature. substance which floats in its atmosphere This recognition of luminous matter ex. This doctrine is now generally received, isting in the universe in a rude, or, as it and we need not discuss its advantages in may be called, elemental state, was of great accounting for the spots on the sun, or the importance towards the formation of a the phenomena attending the revolution of that ory. The small circular or rather globular luminary on its axis. Herschel believed nebulæ may be looked upon as luminaries that the sun is inhabited; but his arguin a more advanced state of growth, and ments to this effect only go to prove, that in some of these, which have an extent we may conceive the atmosphere of the equal to about a tenth of the moon's sur- sun to be so constituted, that the solar face, Herschel calculated that there are at nucleus suffers no inconvenience from the least 20,000 stars. To him also belong the proximity of that circumambient heat and important remarks that the nebulæ lie for light which enliven the solar system. Other the most part in strata, and that the heavens and better arguments, as M. Arago intiin their immediate vicinity are generally mates, may still be urged in favor of that quite free from stars.

opinion. The favorite object of Herschel's study We cannot refrain from turning aside for and contemplation was the Milky-way. an instant from the grave review of these That also he considered to be a stratum of speculations and discoveries, to glance at stars, in the middle of which nearly is our the fate of an unconscious fellow-laborer of sun. But this was not the speculation of Herschel. Had this wonderful man been a mere theorist. Though his bold genius unpensioned he could never have dared to has enlarged the bounds

of Astronomy, yet I publish so many new and bold opinions.

Fortunate as he was, and the favorite of apply the common maxim "noscitur a soa king, he has yet been sneered at for what ciis." No definitions can safely decide has been deemed a constant hankering what is monomania and what is not; no after the prodigious; but there can be no act of parliament can mark the exact line doubt that much of what the world ac- which separates madness from philosophy, cepted as philosophy from him, would have poetry, or love. At the present day, when been thought madness in one less advan. there is such a call for a law on monotageously circumstanced.

mania which shall settle to a nicety the It happened that in 1787 Miss Boydell, degree of mental obliquity entitled to huthe niece of Alderman Boydell, was shot mane treatment, and which, by exact defiat in the street by a man who was arrested nitions, shall teach us “insanire ratione on tbe spot. Her clothes were set on fire, modoque;" it may not be amiss to call at. but she suffered no serious injury, and intention to the difficulties surrounding such deed it was never proved that the pistols an attempt. were loaded with any thing destructive. By a natural transition, we pass from a The prisoner turned out to be a medical case of lunacy to the moon. An immense practitioner named Elliot. On his trial the height was formerly ascribed to the moundefence set up was insanity, in proof of tains in our satellite. Galileo estimated which Dr. Simmons, physician to St. their general elevation at nearly 30,000 Luke's, came forward among other wit- feet. Hevelius, more accurate, reduced nesses. The Doctor, in order to show the them to 17,000 feet. Herschel, however, disordered state of the unhappy man's lowered to 9,000 feet the highest of the mind, produced in court a paper which lunar mountains, and to the generality of Elliot had sent to him, for the purpose of them he allowed but a very moderate elevabeing presented to the Royal Society, but tion. In this particular he is at variance which the Doctor thought too visionary with those who have followed him in the for that learned body. He called the at- same line of inquiry. According to Beer tention of the court particularly to a pas. and Maedler, who have bestowed so much sage, in which the author asserted “that care on the study of the moon, there are the sun is not a body of fire as hath been in that satellite six mountains exceeding hitherto supposed, but that its light pro- Cotopaxi in height, and twenty-two which ceeds from a dense and universal aurora, rise above the elevation of Mont Blanc. which may afford ample light to the in- In reference to the disagreement existing habitants of that body's surface beneath, between the conclusions of recent Selenoand yet be at such a distance aloft as not graphists and those of Herschel, the acute to annoy them. No objection," he pro- and impartial M. Arago makes an observaceeds to say, "ariseth to that luminary's tion which deserves to be well weighed by being inhabited, and vegetation may obtain those inimical to the reputation of the there as well as with us. There may be latter. “Allow me to remark,” he says, water and dry land, hills and dales, rain “how incompatible the conclusion hazard. and fair weather; and as the light, so the ed by Herschel is, with that affectation of season must be eternal; consequently it the extraordinary and gigantic, which some may be easily conceived' to be by far the have maintained on very slight grounds, to most blissful habitation of the whole sys- have been the characteristic of that illustem.” Here then we find adduced as a trious astronomer.” proof of the madness of Mr. Elliot, the very « The active volcanoes which Herschel doctrine which Herschel promulgated with fancied that he could descry in the moon, much applause eight years later.

were doubtless optical delusions, or else The Recorder, who tried Elliot, held that spots on the moon's surface, illuminated extravagant opinions are no proof of mono- from the earth. We have already menmania. "We are disposed to think that, in tioned his discovery of the remote planet this particular case, the physician of St. named by him the Georgium Sidus, but to Luke's was better qualified to decide than which continental astronomers persisted in the judge.* To a man's opinions we may giving his name, and which is now, by

general consent, called Uranus.

Seven Elliot was acquitted under the indictment for years elapsed before he could discover any an attempt to murder, but was ordered to be tried satellites attached to the new planet; his for the assault. Chagrined at his detention in perseverance, however, and the perfection prison, he refused food, and died on the twelfth day of his telescopes, were at length rewarded the “ Gentleman's Magazine," for 1787, pp. 636 with the discovery of six. Some of these and 645.

satellites are so minute, and, owing to their

obscurity, so hard to be detected, that mena, than to engage in computation, or
doubts have even been thrown on their ex. the more arduous and essential, though
istence. It is therefore not unimportant less fascinating labors, through which the
to observe that M. Lamont, of Munich, ob- science can be really benefited.” It griev.
served in 1837, one of those which had been ed us to read this shallow and ill-considered
so long missing. On the whole, the dis. judgınent in the “ History of Astronomy."
covery of Uranus, and its satellites, may in the last edition of the “Encyclopædia
be justly reckoned among the inostre. Britannica.”
markable additions made to astronomy in Herschel was not only a great man; be
modern times.

was also a most fortunate man. He was We have said nothing of the pains taken fortunate in having George III. for a patron. by Herschel to examine the rings of Saturn; Again he was fortunate in baving M. Arago nor of bis Memoirs on the optical pheno- for a biographer, who, while complete masmena called the Newtonian rings; nor of ter of his subject, is also a gentleman suhis discovery that heat and light have not perior to envy, and capable of sympathizing exactly the same refrangibility. Yet when with the truly great. Thrice fortunate he showed that in the solar spectrum form. was he in transmitting his name and fame ed by refraction with a prism, the thermo- to one who, with the amplest intellectual meter rises higher beyond the limit of the resources of an accomplished scholar and red rays than in any, even the brightest, philosopher, evidently cherishes the chapart of the spectrum, he led the way to in-racteristic boldness of his father's spirit, quiries which have since yielded the most and upholds that liberty of conjecture which important results. Regard to our limits, is indeed the mainspring of sagacity. Sir however obliges us to pass over in silence, John Herschel has observed about 2500 as many of his ingenious disquisitions as nebulæ, and perhaps 2000 double stars in would suffice to make the reputation of an the southern hemisphere. He has detected ordinary man.

among them ample evidence of that change The degree of Doctor was conferred on and revolution which had fixed his father's Herschel by the University of Oxford in attention. When we consider that the 1786, and thirty years later he was made Herschels, father and son, have carefully a knight of the Hanoverian order of the examined the whole starry firmament with Guelfs. He died in his eighty-third year, 20 feet telescopes-instruments of which, on the 23d of August, 1822.

in tbeir present state of perfection, the “ For some years before his death,” says bis elder of them may be said to have been the biographer, “ he enjoyed the purest delighi from inventor—and that they have made known the distinguished success of his only son.

In to us thousands of the most interesting his last moments he closed his eyes in the grate sidereal phenomena, it appears to us hardly ful thought that that beloved son, the inheritor an exaggeration to say, that Astronomy, of a great name, would not allow it to sink, but beyond our own system, rests chiefly on would even clothe it with fresh lustre, and that

their labors. great discoveries would also adorn his career. No prediction of the illustrious astronomer has

It is generally understood that the one ever been more fully realized.”

sole object of Sir John Herschel's labors

is to complete those of his father, and to The sketch which we have given of develop fully those views respecting the Herschel's discoveries will be sufficient to Construction of the Universe which, when show that his mind was at once the boldest demonstated, will immortalize its author. and the most practical. Skilful, and un- For such an undertaking, Sir John Herschel conquerably persevering as a contriver, has inexhaustible materials in the journals constructor, and observer, he was bold even of the observatory at Slough; he has col. to temerity in his speculations, but his bold- lected all the evidence which the southern ness was always guided by great natural hemisphere can supply; and inspired, as penetration. Yet this great man has not he is, by a noble and pious purpose, we escaped the censure of those modish phi- doubt not that his work, whenever it shall losophers who, measuring by the standard appear, will be reckoned one of the most of their own minds, would restrain all remarkable monuments of modern science. speculations within narrow limits. One of this school, after mentioning Herschel's sixty-nine memoirs, adds, "A great part of these, however, is filled with speculations

Milton.-A large tablet to the memory of Milof no value to astronomy; and his taste last. It bears for an inscription Dryden's well

ton was erected in Allhallows Church on Monday was rather to observe astronomical pheno-known sextain.- Court Journal.

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