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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 under unexplored.
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 pow. 28 added by Lacaille, made up a lotal of 96. erful the telescope, the less the apparent This branch of science took a rapid Right, 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. In 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, to 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 from 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 eup- 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. Attained 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 of 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 accu.
apparent diameter. But the perfection 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. Kepler believed the diameter of ai once among the most eminent astrono- Sirius to be four minutes; Tycho Brabe mers. He turned his attention to the supposed that stars of the first magnitude changes taking place in the sidereal hea: 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, so numerous and exact as to suffice for the tinually reduced, till at length Cassini as
measures, or rather estimates, were conbasis 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, which he the astronomer of Slough could furnish
to be double of the true diameter.
supposes several other examples, but the following the value of these observations may be 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 Flamsteed's catalogue as a star of the fifth the share which illusions of vision have 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."
lions 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,
9000 millions of leagues. The determination of ness at regular intervals of time, and
he would still leave 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,
four millions of leagues, which is still eleven the British Association at its last meeting,
it will be here sufficient to state briefly,
that he found the parallax of a small star,
“So far," observes M. Arago, “astronomers
inextricable irregularities of the sidereal motions, towards the decision of this interesting the solar systein ; and finally, that the point 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 slar ; 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 Hersche's chief titles to re
the discoveries of one whose work was
VOL. II. No. IV. 36
sion of the most powerful instruments, ad-fthis science oves 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 hosts that these atmospheres, 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 luminous, will yet be found by an experivery plausible. The recollection of the Zodiacal light--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 “Every thing justifies the opinion of the in their centre condensations of light more or illustrious astronomer. In the course of less decided, will present themselves to the imagination as the first outlines of stars, or as a ager, the clustering power (this is Her. state of luminous matter intermediate between schel's expression) will inevitably bring the uniformly diffused nebula 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 vigilaut 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 revolation of that ory. The small circular or rather globular luminary on its axis. Herschel believed nebulæ
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 so:
yet been . has been deerned 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 shoi mane treatment, and which, by exact defi. at in the street by a man who was arrested nitions, shall teach us “insanire ratione on the spot. Her clothes were set on fire, modoque;" it may not be amiss to call atbut 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 moun. defence 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 with 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 hazardand 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 after his acquittal, He was assuredly insane. See with the discovery of six. Some of these the “Gentleman's Magazine,” for 1787, pp. 636 and 645.
satellites are so minute, and, owing to their obscurity, so hard to be detected, that I mena, than to engage in computation, or doubts have even been thrown on their ex. the more arduous and essential, ibough 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, une of those which had been ed us to read this shallow and ill-considered so long missing. On the whole, the dis- judgment in the "History of Astronomy" covery of Uranus, and its satellites, may in the last edition of the “Encyclopædia be justly reckoned among the most re. Britannica." markable additions made to astronomy in Herschel was not only a freat man; he 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. hy Herschel to examine the rings of Saturn; Again he was fortunate in having M. Arago nor of his 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 genileman suhis discovery that beat 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 forin. 'as 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 resuïts. 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 Guells. He died in his eighty-third year, 20 feet telescopes—instruments of which, on the 23d of August, 1822.
in their present state of perfection, the "For some years before his death,” says his elder of them may be said to have been the biographer," he enjoyed the purest delight 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 phenomenn, 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 10 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
Milton.-A large tablet to the memory of Milthese, however, is filled with speculations of 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.