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to have no superior for delicate accuracy in the stars, so many of which have been recorded in comparison of the magnitudes and varied colours of the annals of Astronomical science. Our thoughts the stars, while the other gentlemen were equally would paturally be carried back three centuries, to eminent for the application of the Spectroscope to the days of Tycho Brahe, who witnessed the sudden the analysis of the nature and sources of stellar apparition of a new star, in brilliancy exceeding the light.
brightest in the heavens, but which he was sure It is surely far from a sign of the decadence of a had not been visible half an hour before. The great country, which like our own, by its natural habits | Danish astronomer, unfortunately for us, had not and free institutions, produces a supply of men, who | the means and appliances which since his day have for no fee or reward, but impelled by the love of the accumulated in the hands of modern observers, and thing, and often when their day's proper work is little else was left for him to do, but to gaze, and done, set themselves, at the cost of expenditure and to guess, and to be astonished. tsil, to consume the hours of midnight in increasing Science, however, during the last few years has the knowledge of their fellow men, and in searching | taken one of those sudden bounds which render its into the wonderful works of the Great Creator. We | annals so fascinating to the student; and especially may be thankful that not a few such men exist in Astronomical science, owing to many causes, has England; and among them none are worthier than recently received a strong impulse in a new directhe three gentlemen whose names have been men tion; and no longer finding the grasp of her powers tioned above.
restricted to the weighing of suns and planets, and I shall now proceed to give the results at which to the measuring of their distances, she now aspires Mr. Baxendell arrived in his examination of this to a loftier aim, and hopes she is henceforth perremarkable star.
... !!mitted by the Supreme Wisdom to understand some On the 15th of May it had decreased from the little of the processes from whence are elaborated koond magnitude, which it had attained when ob the heat and the light of the sun, and what are served at Tuam, to nearer the fourth than the third | the sources of even those paler fires which come magnitude when first seen by Mr. Baxendell'at spangling to us from the more distant stars. Manchester. It then continued to diminish with The means by which this unexpected accession to very great rapidity, until on the 26th of Jupe it our knowledge has been obtained, the long train had sunk to nearly the tenth magnitude, and thus of ingenious experiments (those questionings of kad ceased to be visible excepting in excellent tele. Nature), and the logical deductions therefrom, scopes alone. .. .
which enable us to say with undoubting confidence, Thus the intensity of the star's light on the 12th of «In yonder star there existe iron at a burning heat; Nay was fully five hundred times greater than on the in another, there is incandescent vapour of lime ; in *th of June ! !
Polvo ....!Lalmost all of them there are strong avis
almost all of them there are strong evidences of the Vor were the variations in colour much less ré. existence of magnesia and salt, and the recent outmartable. When first seen there was a slight ne burst in the remarkable star of which we have Imkeity about it, and there was a bluish tinge, as spoken, was owing, in part at least, to the sudden
the yellow of the star were seen through an over combustion of hydrogen gas :" these things—we lying film of a blue tint. After the 25th of May may almost call them wonderful things we shall this bluish tinge disappeared, and the colour changed now proceed to lay before the reader. through many various tints of orange and yellow. | In so doing, we fear we shall of necessity make a
From the 26th of June to the 20th of August, serious call upon his attention ; but, in return, things remained without observable change, but, we promise him a rich reward for his exercise of
strange to say, a second outburst of light commenced patience. On the other hand, out of the hundreds in the latter date. By the 15th of September it of thousands who will read these lines, there are
had risen two magnitudes, that is to say, its light probably some few who are as familiar as the writer had again become sicfold. The star then remained with the simple but beautiful experiments we shall apparently tranquil until the 9th of November, find it necessary to describe. But, even to these when it once more began to decline, and at the few, it can scarcely fail to be pleasant to travel once present time has nearly diminished to its least ob-again over fields which, after all, present an inserved intensity. Its colour varied from a pretty exhaustible variety; for there are visions of glory bright yellow on the 17th of Septernber, to a light which never satiate, and there are truths the conmange on November the 6th, and then fading templation of whose comprehensive simplicity never
through a dull orange, is now of a dullish white. palls. Among such, we venture to believe, are the ' If the state of our scientific knowledge were now laws of interaction which the Supreme Wisdom has
no further advanced than it was abont seven years impressed upon the material elements which are ago, there could be no definite conclusions relative scattered in almost unbroken continuity through to these two singular outbursts of light, which the universe of things. could safely be drawn, even from the elaborate and We strongly advise the great majority of our accurate observations of Mr. Baxendell. Nearly all readers to repeat the experiments we shall detail. that eould be said would be, that we have here one with this end in view, we shall describe them of the most remarkable instances of those variable simply and fully; and, moreover, we shall in
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12om Dos tentionally select such as require no great degree of bably he may see a variety of beautiful coloured skill, and involve no apparatus beyond such as is bands flitting about, but what he seeks is the ributterly inexpensive, and can now be procured in bon, which proceeds from the light of the slit, and most houses and every village. rituoso villains this he may distinguish from all the others, by re
Let the reader, then, who desires to follow the questing an assistant to cover over the slit itself train of our reasoning, take a piece of cardboard or with a finger, from time to time. ait aidt yvigource stiff paper, about a foot or eighteen inches square ; to When the experimenter has at last caught the any colour is somewhat better than white, and it sight of this beautiful coloured ribbon, or spectrum, must be impervious to the light. In the middle of as we shall now call it, he will find that, as he this, carefully cut a clean aud even straight slit, humours the glass (always holding its edge vertical) parallel to one of the sides, not more than the the spectrum itself will greatly vary in length and twentieth of an inch wide, and about an inch and a in its distance to the left of the slit ; The must then half long. Fix this opaque paper, with wafers or so place the glass as to obtain the shortest spectrum otherwise, i against a clean pane of glass in the he can, and then he must gradually open it out a
window of a room, so that the thin slit shall be little. If he has succeeded, and unless the glass be ano wako vis vi modt dust 159 10109
92901 Sotodrome very uneven and full of veins,
he will now see something not very dissimilar to the subjoined
engraving agail szedt 25897 L3D The colour near to c is red,
s towards Dit becomes orange, ve and then, a little, yellow, and
then green, and about the 91.9 to
colour is blue. But what he is 9:13 Diagram of the Compound Spectrum of the Teruporarily Bright Star, 75tBwon especially to look for (and what,
sib 30 ani a bolo 5 Gorona Borealis. saiosa o ato IMOT wo Savbe in fact, is the object of the boog niwir ei od olid viiulit bua tu bollt veel betejanouwhole experiment), is the prevertically, upright, and at a height from the floor sence of one, or two, or three, or four, black vertical equal to the height of the obseryer's eyes
lines, like the lines C, D, and y, in the diagram. The Now let him take a glass lustre off a chandelier. writer himself, after a careless experiment like the It will be best for him to select two or three, with one described, at this moment, on a dull day, sec out veins, if such can fortunately be found, and two lines, namely, D and F. As we have already much the better if the shape of the glass pendant said, the sight of these dark lines is the object of happens to be, in section, an equilateral triangle; the search. They are not to be seen without patience: but in modern fashion these glass pendants for the few philosophers are even now aware that they can most part have two of their faces perpendicular to be seen at all with so rude an apparatus ; and when each other. Through this rectangular edge vision they were for the first time observed by our great is impossible, and the reader must avoid it. Now I countryman Dr. Wollaston, in 1802, they immor let him stand with bis right eye exactly opposite to talised the discoverer. Chiw mid dedi aoga bata the slit, and if he can, through the slit, see a bright Jens Thirteen years after this, Fraunhofer, at Maniel, white cloud, that will be in his favour: his distance by diminishing the breadth of the slit, by reflecting from the slit may be eight, or ten, or twelve feet, the direct sun-light through it from a looking-glass or even more. The lustre is to be held with one of outside, by then using a prism of pure glass, and, its acute edges (not the rectangular edge, if it has lastly, by looking at the slit through the prism, not one) vertically upright, and therefore parallel to the with the naked eye, but with a small telescope, 96-1 slit and close to his right eye, and with this eye he served and accurately measured the position of is to look through the left hand face of the glass. many hundreds of these lines. Without a telescope, The direction also in which he must look must be if the reader possesses a tolerably good prisin, he towards the left, and, as it were, to some place on may readily see more lines than he can count. the left not quite so far from the slit as he is him. These lines have henceforth been called Fraunself distant from it. He will then see the thin line hofer's Lines. In fact of priority, they are Wollasof light from the slit spread out into a ribbon ton's ; but, unfortunately, our countryman did not coloured with a variety of successive colours. The at once see the importance of his discovery, and red colour will be nearest to the slit, on the right; he dropped the subject. Newton also, who a cenand the blue will be furthest, on the left. To see tury before Wollaston first observed and studied this ribbon of coloured lights will require patience the spectrum, lost the fame of this discovery from and some humouring of the glass lustre ; but to the the simple fact of not placing the prism close to his writer, who, nevertheless, bears in mind Columbus's eye. a toa b omo
odred egg, the whole actual manipulation at this moment Strange to say, these dark lines contain the key has occupied less time than the description. The to the enigma of the material constitution of a star, render may consider himself fortunate if his own and of our sun; and that is the reason why we success requires twenty minutes to achieve. Pro. have been thus particular in describing the easiest
and most simple way of seeing a few of the most The next step in advance was taken by Professor conspicuous among them, namely, c, d, and F. ; Wheatstone, about three years after Brewster's dis
The reader will probably have little or no diffi- covery of the absorption of certain lights by certain culty in 'understanding that the coloured ribbon of coloured vapours. By a process of considerable light, called the spectrum, is nothing more than difficulty he contrived to render the vapours of the thin line of light in the slit, spread orit. He may certain of the metals incandescent; and then viewconceive this line to resemble å bundle of indú- ing the light emitted by these vapours through a tierable coloured faggots, and that the glass or slit and prism, as before, he found that the spectra prism, through which they have passed, has did not consist of a continuous coloured ribbon of arranged them all in an orderly manner. But then light, but simply of a few detached bright coloured comes the question, What is the significance of the lines. The incandescent vapours of no two metals dark interruptions? Do tlie colours which would gave precisely the same lines. In fact, so extremely otherwise properly belong to these dark spaces, not definite was the spectrum of each metallic vapour, least in the natare of things? Or do they not exist that Professor Wheatstone did not hesitate to say in solar light? Or do they in reality exist in light that by this method the presence of extremely emanating from the sun, but subsequently have minute portions of the metals could be detected been absorbed somehow and somewhere? These with greater certainty than by any other known dre Datural, inevitable questions occurring in rela- process. tion to Fraunhofer's lines; but for upwards of fifty | The reader may easily try the experiment on a years these lines remained a perplexing mystery. small scale for himself, by burning a little magThe Sphinx had spoken, but Edipus was not. Who nesium wire (now, thanks to the wide diffusion of conld have conceived that the true solution lay in scientific knowledge, so easily procured,) behind the the existence of heated terrestrial substances dis- slit, when he will at once recognise a peculiar persed in the sun and throughout the universe ? spectrum of certain bright greenish lines. Or if he
In 1832- that is just thirty years after their dis- drop a little salt into the flame of a lamp or candle, covery by Wollaston-Dr. Brewster, by a very will immediately see a bright yellow line in the simple experiment (wbich we advise our readers to precise position of the line marked p in the diarepeat, however roughly), demonstrated that these gram. And further, if while he is viewing a good dark lines are produced by the absorption of those spectrum of the light from the candle, an assistant particular coloured lights which, in the spectrum, opens and shuts with some violence an old dusty they displace. Let the reader take a candle or a book close to the light, he will probably see, for the lamp, and in front of it let him place the narrow moment, a vast iumber of bright-coloured lines elit as before,' and let him as before obtain the suddenly start into existence throughout the specspectrum of the light ; 'he will then see the same trum.! These lines arise from the vapourization Sort of beautiful coloured ribbon with which by and incandescence of a vast number of minute subthis time he must be familiar; but he will see no stances collected in the dust. ',.'
' | dark lines, it will be continuous and uninterrupted, But these lines in the spectra of metallié vapours
But now let him procure à small uncut glass and the same remark applies 'equally to incandescent tumbler, in it let him placé some small copper coin, gases, such as hydrogen, &c., -are all bright lines, and upon it let him, with all necessary caution, whereas those in the solar spectrum are dark. pour as much aquafortis (or nitric acid) as will just what, then, is the relation between the two ? keover the coin, and immediately place a paper cover And now came a variety of guesses ; one might 06 the top, in order to confine the orange-coloured almost call them divinations of the truth. The Papours of nitrous gas which will presently fill the annals of Science tell us that such divinations of Nad This class is to be quickly placed between truth beforehand pot rarely precede the discovery the light and the slit, and the spectrum is now' to of great, comprehensive, pregnant truths. They be observed. It is no longer the bright uninter. | preceded the discovery of the Law of Gravitation ; mupted spectrum which he had seen from the lamp they preceded the discovery of oxygen they prebefore, but the coloured ribbon 'is crossed with a ceded the discovery of electromagnetism ;'and even wnltitude of lines, greatly resembling, but not now they seem to loom before the discovery of the identical, with the lines discovered by Fraunhofer, yet unknown cause of gravitation itself. Newton The experiment, if well performed, is extremely divined the 'combustible nature of the diamond a bextitiful, and one not likely to be forgotten. Here century before Allen and Pepys succeeded in showthere is a demonstrated fact, that 'media do exist ing it was nothing but pure crystalized carbon. "... capable of absorbing light, and of producing' a' But what is it--- we may ask-what is it which, phenomenon closely resembling the dark lines in as it were, causes coming and substaüitial disthe solar spectrum. vedi
-* coveries so often' to throw their shadows before | But there comes the question, What is it that them? 'Is it some single word, or some chance exabsorbs certain portions of the solar light? Is it pression, which, as a winged seed falling from one sémething in the atmosphere of the sun, or some- 'master-mind, is wafted, like a rumour, 'amongst thing in the atmosphere of the earth? Thus the other minds, until, at length, it finds a proper and wystery became increased! 1,2,3 tot so l is SRB sil) giulis vai utitur minds me orci l kipared hoine, and then germiuates aud fructifies
into the ripeness of some general truth? Or is it spectra lay superposed before him, and admitted that the minds of men, after some unknown process, the most exact comparison. The iron spectrum and in accordance with some magnificent pre- consisted of thirty or more definite and widely arrangement of the Great Eternal Mind, become, separated bright lines, and these were absolutely from time to time, by the interaction of circum- coincident with as many dark lines in the solar stances, polarised, and when the tension becomes spectrum. This coincidence of so many lines, and oi extreme, break forth at length into the force and all of them, could not arise from chance, but demon. light of discovery?
strated the existence of heated iron vapour absorb. Be all this as it may, it is certain, that Professor ing certain qualities of light emanating from the Stokes, in England; Balfour Stewart, in Scotland; M. incandescent body of the sun. And in the same Foucault, in France; and M. Angström, in Sweden, manner Kirchhoff obtained the spectrum of incanall assigned a probable cause for portions, at least, descent hydrogen superposed upon the solar specof the obscure but interesting phenomena before us, trum. The hydrogen spectrum cousisted mainly of and had any one of them followed up his reasoning the bright lines c and F of the diagram on page 272, but one step onwards, he would have anticipated in absolute coincidence with two of the lines dis. the grand discovery of Kirchhoff which, in 1859, covered by Wollaston, and marked by Fraunhofer grasped the whole question, and soon laid open to with the same letters o and F. Hydrogen, there the human mind very much of the material con fore, exists in the atmosphere of the sun, and it stitution of the sun, the stars, nebulæ, and comets. stops or absorbs the red light c and the bluish
What Kirchhoff did was virtually this. He de- green light F, which emanate from its incandescent monstrated experimentally that if the vapour of a nucleus. metal, or a gas, when incandescent, emits light of a The reader is now in a condition to intelligently certain quality, that same metallic vapour or gas, understand the evidence upon which we conclude when less heated, absorbs precisely the same quality that the remarkable outburst of light in the star, of light. The vapour of sodium, for instance, when which has been described in the former part of this sufficiently heated, emits a bright yellow light, all article, probable arose from, or was accompanied of which is coincident with the dark line D of the by, a couflagration of hydrogen gas. On the night solar spectrum ; but if this light be made to pass of the morning when the intelligence reached Pro through vapour of sodium less heated than the fessor Miller and Mr. Huggins, relative to the sudemitting vapour, it will be absorbed entirely, and no den appearance of the star, they at once viewed its light at all will be visible, Aud so with other spectrum with the same admirable apparatus which metals and various gases. Here, then, was not had already conducted them to so many important only a clear explanation of the origin of Wollaston's discoveries connected with the physical constitution or Fraunhofer's lines, but an insight is thereby of the heavenly bodies. But what a sight was there given into the material constitution of the sun : revealed to the well-practised initiated eye of s and the same remark applies equally to the stars. philosopher! There lay before then the evidence
The sun, or the star, must be considered as con. which suggested the atmosphere of a star, a stiu, i sisting, first, of some nucleus with its solid or world, on fire. And the evidence was this: the liquid surface intensely heated, so that the light instrument revealed two spectra, the one superposed emitted from it, like the light from every other in- upon the other: one of them was the usual species tensely heated solid or liquid with which we are of spectrum generally afforded by the stars, viz, s' acquaiuted, affords & continuous uninterrupted spectrum interrupted, as we have seen the sole
im. In froot of the incandescent surface spectrum is, by numerous dark lines, and indicating must be various heated gases and metallic vapours, for the star, an incandescent solid or liquid nucleut, and each of these stops precisely those qualities of surrounded by an atmosphere containing the vapour light which, if more intensely heated, it would of sodiuin, and it may be iron, or magnesium, of emit. *
various other elements which are fouud upon this There was but one step more to be taken, in our earth. But besides this spectrum there is order to prove incontestably that such metals as another, and that other full of a remarkable signil. iron, sodium, magnesium, &c., and such gases as cance. It consisted of four bright lines, and from hydrogen, &c., do actually exist in the sun and in their relative position two of them appeared to arise the stars. Kirchhoff took this step. Through the from INCANDESCENT HYDROGEN." This, within their lower half of the slit, so often spoken of, he ad- knowledge and experience, was a solecism in the mitted solar light, and obtained its spectruun; heavens. Of the dark lines c and F in the spectra through the upper half he aclmitted the light of stars, evidence enough existed; the significauce of emanating from various incandescent metallic va- these lines was hydrogen indeed, but of hydrogen pours, from iron, for instance. Thus the two not heated to extreme incandescence. 'Here, how
ever, the lines c and y were brighter than the con It is important here to observe that the less intensely tiguous parts of the spectrum, and thus they spoke heated vapours themselves emit some rays of the sanie unmistakably for themselves. But so far the coquality or refrangibility as those which they have wholly | absorbed; but tbese are so feeble as to appear dark when incidence of two of the bright lines with c and To contrasted with the adjacent lights in the spectrum. i. Fraunhofer was rather suspected than prored, an
consequently these cautious experimentalists put tinge may be seen in perfection when the wind into requisition the exquisite apparatus and arrange- blows over and provides a supply of oxygen for an Dents with which they were provided. They pro- illumination by gas. Such a state of things would duced the spectrum itself of incandescent hydrogen, also go far to explain the great variability in the vi they placed it exactly over the spectrum of the colour of the star. The collision of an oceanless
r; the coincidence of two of the bright lines of satellite would consistently account for the second tie star with the two bright lines of incandescent and smaller outburst. But we are confessedly in Zydrogen was absolute. The other two bright lines the regions of speculation, and there let us leave the of the star are not ascertained as yet to indicate the subject, or at all events this truly hypothetical esistence of any element known to the inhabitants part of it. this earth.
In tlie course of this article we have been speakThus the sudden outburst of light in this star, oring of many things, in the contemplation of which all events the light of the star, was in great part it is difficult to silence the imagination, and somekaet owing to hydrogen. As the light of the star times equally so to suppress a rising emotion. What mated, so the splendour of these bright lines waned, are we to say, for instance, of the evidence which
und so also the other continuous spectrum declined such researches have brought to light, of that scat2a brightness, and we are in a manner forced upon tering of material substances in patches as it were I the conviction that the outburst of light was ac- throughout the universe, just as, in like patches,
coispanied with the blaze of hydrogen in com- we find metallic substances scattered in various cestion, which gradually spent itself, and is now parts of our own earth? Some stars, we have seen, Dearly extinguished.
afford evidences of the existence of iron and lime, But is it possible to make even any plausible and others do not; most of those hitherto examined guess as to the cause of the outburst of light and contain magnesium, and almost all of them sodium. heat in this wonderful star? Thoughtful men have Of gold, and of silver, so far, they contain not a arrady made some guesses, and we shall now trace; shall we here then repeat the remark which tature upon another; it is given simply as a guess | centuries ago Tacitus made regarding the ancient wd as a mere speculation only, though we hope Germans :-"arrum et argentum, dii irati an proat wholly an uninstructive one in
| pitii negaverint, dubito." On referring to the Royal Observatory, Green. And lastly, there is another thought regarding wuch, it was soon discovered that this star, now this Stella Mirabilis, 'which we have already briefly alled T Coronæ Borealis, is not a new star, but was touched on, and with it we shall conclude. It has Pery probably observed by Sir W. Herschel, and by reference to the inconceivable distance of a body of 6. Wollaston; and certainly it is in the catalogue whose material constitution we nevertheless make, di M. Argelander, and is there marked as a star of and reasonably make, such confident assertions, between the ninth and tenth magnitude ; just the and regarding a possible catastrophe in which we able brilliance to which it has now sunk. If this have ventured, though not without reserve, to
ar be like other suns, there will be worlds circling | speculate. The thought is this : the conflagration Titd it, and these worlds. may like our earth have in this atmosphere of a star was first observed on katellites. Now it is the settled opinion of some the 12th of May, 1866 ; but when did it actually
itious philosophers that in the lapse of ages, that occur ? If this star is as near to this our world as Aster the lapse of many millions of years--we do is the nearest yet known of the stars, which prox
say millions of millions of years-the sun will imity nevertheless we have no reason to supposé, are lost the greater part of its heat and light, and then the increased outburst of the combustion of Der earth and its satellite will at length approach it hydrogen must have taken place at least three
hrer and nearer, and ultimately will rush into the years before it was visible at Tuam and inter22 darkened luminary; then utter indeed will be preted at Tulse Hill. But if, as is far more pro
ruin, and vast the outburst of light from the bable, this star is among those more distant orbs Take thereof. There is nothing chimerical, nothing which shine with a light so pale as to be visible pulosophical in the belief or the expectation of only in our more powerful telescopes, then the con
ultimate phenomenon. But the time is not flagration, of which the first tidings have reached 34 .
i us only to-day, must have actually waxed and [Sow it may have been that the outburst of light in waned for its little week, 'not now, nor yesterday,
Curopæ may have arisen from the falling into it, but it may be even hundreds of years ago. The Si of a world like our own, and subsequently of its imagination shrinks within itself at the thought, batelite. Such an hypothesis is somewhat consistent how the bright light from that evanescent epheme
th the greater, and with the lesser outburst ral outburst, winged its way, leaping century Which succeeded the former. If the world in col through century, from world to world, and telling hun was provided with a great ocean i like our successively the tale of its glory to (it may be)
2, then there is the source of the hydrogen ; and creatures nobler and more intelligent than ourLas it cooled somewhat, it recombined with the selves, at length reaches the little speck of our Wajnen, we can account for that peculiar blue tinge mortal abode, in its course onward we know not *ekh Mr. Baxendell observed, and which blue whither. But let us remember it is not the prism,