THE MATERIALS OF THE UNIVERSE.

From Fraser's Magazine. a hundred substances - each a compound in itself. From the chemists, who are the only authorities upon this subject, we learn that there are about 62 elements at present known, of which 49 are metals, 8 substances with an individual character of their own, which does not admit of their being ranked with the preceding, and 5 gases. Such appear to be the materials of which our globe is composed. We cannot affirm it to be matter of demonstration that none of these may be some day found reducible to a more simple form. We cannot pronounce with mathematical confidence that no unexpected and startling discovery may yet effect at least a partial change in some of these positions. But we may safely affirm, from the accordance of rigid theory with accurate and extensive observation, that the probability of any general revolution in chemical knowledge is almost infinitesimally small; and though we cannot as yet claim the reduction of every stronghold, we may believe that the ground which has been won during the present century is effectually secured from becoming again the possession of ignorance and uncertainty.

To some of our readers the title of this paper might seem to involve a degree of assumption; to others, a want of sense. We hope to prove, in a short time, that it does not justly incur either imputation. As to want of sense-though even in scientific matters traces may occasionally be found of that minus quantity, and followers may still exist of him, who, when it was supposed that a geometrical figure had been discovered in the moon, proposed to trace out something similar in the plains of Siberia, by way of opening a communication with our neighbours across the sky, we trust that all we have to say will be amenable to sound reason. And as to the idea of too great pretension, it would have undoubtedly attached to any attempt to speak of all the materials which the Creator has seen fit to employ; but we have carefully avoided any such extensive epithet. Our aim is merely to show, in a simple and intelligible way, and as far as may be fairly expected in a rough and general outline, what has been ascertained as to the elements of the creation at largea wonderful subject, and deserving of far better handling.

We may say, therefore, without presumption, that we know pretty well of what our But, first of all, we have to define the globe is made. Then comes the interesting term element,' and to describe the extent inquiry, Is the rest of the universe comof its application. By an element,' it is posed of similar, or of entirely unknown scarcely necessary to say, is meant a sim-materials? Sun, moon, and stars, what ple substance, which, so far as our means are they in their actual nature and ultimate of investigation extend, is incapable of de- composition? We see their light; in indicomposition, or reduction to any more vidual cases we can detect something of primitive form. And we may presume the arrangement of their surfaces; but upon our readers' knowledge of the fact what is their chemical character? Of what though some experience in teaching leads are they made? Are the elements that we us to be careful even as to this presump- here know the sole substratum everywhere tion- that the 'four elements,' universally employed by the Great Creator as the recognised as such but two or three gen- foundation of His glorious work? Or has erations ago, have entirely disappeared He seen fit to employ, in other places of from the list. Not one of them is now His dominion, materials, to us wholly, or considered a simple body. Air is known it may be only in part, unknown? to be a mixture of two transparent gases, It is a daring question; and but a few nitrogen and oxygen. Water is a com- years back would have been almost a hopepound of oxygen and hydrogen, another less one. How could it be possible to regas. Even in fire, the light and heat may ply to it? We have no means of bridging be separated, and it is now generally ad- over that wide gulf that separates us from mitted that each may be reducible to a every other body of our system. One subtle form of motion. And earth is but strange and singular exception must inthe common name of — we had almost said deed be mentioned. Irom time to time a

messenger reaches us from the outward ence has been found capable of reveal

ing to us secrets as to their nature perfectly unsuspected. We have now learned, so to speak, to dissect it, to separate it into its component parts, and to cause some at least of those parts to tell us the mystery of their origin. To explain, in as simple a mode as we can, how this marvellous disclosure has been brought about, will be the object of the following remarks.

space, much more frequently indeed than might be supposed; it has been calculated that on some part or other of our planet an aërolite descends daily. Wonderful things these strangers are, flying as it would seem by millions through every portion of our orbit at random but that the Creator does nothing at random — and very singular is usually their appearance, and very unlike that of the ordinary materials around That ordinary or white light may be deus. But whatever may be their aspect, they composed by refraction into what are combring us much less intelligence than might monly known as the 'colours of the rainhave been supposed. Not being of the bow,' is a familiar fact. Every transparent earth, we might reasonably as well as substance, of greater density than that of eagerly inquire what news they convey; air, and bounded by surfaces inclined to but strange to say, there has not as yet one another, gives evidence of this disperbeen discovered a single element not al- sion, as the separation into colour is techready existing here, nor, indeed, so much nically called. We see it in the drops that in number as a third of those already fall from the clouds, or glitter upon the known. Wherever they may come from, branches, or are dashed into fragments by or whatever may be their destination, they the fury of the cataract. We see it in the lead us but to the negative conclusion, that flashing hues of the diamond, and often to there is no evidence, so far, of any other great advantage in the pendents of chandeconstitution in the distant regions of this liers: but it is most conveniently and pergreat universe, than that which we already fectly exhibited by what is called a prism; know. And, so far, our question is left in -a piece of glass having two surfaces its original hopelessness. In fact, if we greatly inclined to each other. Light, have oftentimes much trouble in ascertain-after passing through any of these dising the chemical composition of substances persive media, is no longer of simple and with which we are hourly familiar, which uniform whiteness; it is transformed into we can not only see, but handle, and a series of the most vivid and delicate weigh, and taste, and smell, and expose tints, melting into each other by an insento all kinds of chemical reaction, what possible gradation, from a dark heavy red, sible prospect can there be that we should through brilliant orange, green, and blue, ascertain the real nature of those to which to a deep tender violet. We are not now we never draw nearer, in the most favourable case, than almost a quarter of a million of miles, while in other instances we are separated from them by hundreds or thousands of millions, and distances passing calculation, and outrunning imagination itself? We see that the bodies are there and that is all we know. It is only by their light that we become aware of their existence.

concerned with the inquiry — though in its own place a most interesting one-how this diversity of hue is universally found where refraction, or bending of the rays of light takes place; and whether colour is so connected with refraction that every progressive degree of refraction produces its own tint-in which case each hue would be simple and independent, - or whether some, at least, of the colours may not be And yet it is that very light that has of of composite character - as indeed every late been made the means of informing us artist would from mere inspection at once of much more than that they are merely conclude. Sir Isaac Newton's division into where we see them. A most unexpected seven colours, having no other basis than advance an advance that but a few years an inadequate analogy with the notes of ago might have been ranked with impossi- music, has dropped out of use, with other bilities has actually been made. That hypotheses; and the question now seems light-the sole indication of their exist- to lie between a superimposition of three

bands of the colours recognised as prima- tributing its own share of light to every ries in painting, red, yellow, and blue, portion of the spectrum, so that the latter, equal in extent but very unequal in in- instead of being a simple decomposition of tensity in different parts of their length; one pencil of light issuing from one point, and a continuous series of literally is an overlapping, to a certain small but innumerable hues, each equally elemen- not inconsiderable degree, of innumerable tary and self-subsistent, and each pass- spectra from an infinite number of luminous. ing, without the least overlapping, into its points, producing a confusion, the limit of neighbours on either side by the most deli- which is of course the apparent breadth of cate and imperceptible modification. The the source of light. Within that confusion, former, the idea of Brewster, is now so that crowding together and intermixture of generally considered as supplanted by the neighbouring tints, some mystery may lie latter, that an attempt to get the cause re- concealed; we shall at any rate naturally heard may be thought to savour of ignor- seek to disentangle it—and fortunately the ance or obstinacy; yet there are those means are ready to our hand. We can willing to take it in hand, and to risk the thin out the crowd to a simple rank, by recharge of temerity in the cause of truth. ducing the visible breadth of the sun to a Experiments of a novel and very interest- single point. Or, better still, since the ing character have been made, and are now tints are mingled and confused only in one in progress, which it would be premature direction, that of the refraction, we may, to describe at present, but which, as far as by means of a slit which can be adjusted to they have gone, have given results not, as any amount of opening, narrow the sun's it seems, capable of explanation on the disc to a mere transverse line of light, more modern hypothesis, but decidedly which, preserving the full breadth of the corroborating the theory of Brewster. spectrum in its own direction, and giving But we will let these pass. Should their ultimate results prove accordant with their existing premise, the public will be invited to judge of their value.

us as it were a ribbon dyed in transverse bands instead of the single parti-coloured thread which would issue from one point of light, makes the phenomenon conspicuous Meanwhile the subject before us is indepen- enough for study, while the confusion arisdent of such researches, and unconnected ing from overlapping is removed. And with any theory of colour. The spectrum, now we shall be able to see whether anyas the band of varied hues is called, when thing has been lying hid in the crowd; and obtained direct from the sun by refraction well shall we find our trouble rewarded. - whether naturally, as through the bow set Thus formed from a single narrow transin the cloud, or the rain-drops pendent on verse streak of light, the spectrum is no the leaves, or artificially, as through a prism longer a continuous band. Its colours reof glass or other suitable material-exhib- main as they were, but it is full of interits to us nothing more than what we have ruptions. It is crossed in innumerable described, a succession of brilliant tints places - the best instruments show uppassing gradually from red of various qual-wards of 2,000-by dark lines, some ities through yellow and green to blue deep- much broader and more conspicuous than ening into violet. But a little considera- others, but all of hair-like minuteness, and tion will show us that these colours, how- in most irregular arrangement and fortuiever uncompounded in their own nature, tous grouping. What is the meaning of cannot, under these circumstances, be re- this strange spectacle? this marvellous and garded as absolutely simple and pure. closely compacted array of intervals of They would be so if the sun were a point; darkness, for the most part so extremely but the breadth of its surface, or in as- thin, yet so perfectly sharp and black, in tronomical language, disc, prevents the that bright beam that seemed just now to complete analysis of its light: for every be nothing but vivid though variegated portion of this disc, from the one side to light? What can there be in the sun to the other, in whatever direction the refrac- give rise to such interruptions in its pure tion may have been effected, has been con- and glorious emanation? Those lines are

evidently characters in an unknown language, which he who reads will have accomplished a more wonderful task than the deciphering of the recovered inscriptions of Nineveh of old. Yet, to a certain extent, they have been read, and they have told strange things. How has this been done?

To explain this, we must bear in mind that the sun is not the only fountain of light. All terrestrial substances, even the gases themselves, when adequately heated, glow out with an intensity proportioned to their temperature, and well depicted in a passage of that noble poem The Forging of the Anchor,' where hyperbole, as in so many other cases, conveys a more faithful, because a more living impression, than any coldly accurate enunciation of bare fact:

flame of the oxy-hydrogen lamp, or more
fierce than either, the mysterious and aw-
ful current of electric power.
A vivid spec-
trum at once streams from the prism; and
we are instantly struck with the difference
in every way from the solar result. Any
solid element thus ignited affords a band of
the same, or nearly the same brilliant col-
ours but without the crossing of a single
dark line. Urge it until it flows down in
fusion, still the unbroken spectrum remains.
But force on the heat till the material rises
into a glowing vapour, and the scene is
changed at once. At once the continuous
spectrum, the uninterrupted stream of col-
our, common to every ignited solid or fluid
element, is converted into a succession of
transverse lines, brilliantly and variously
tinted according to their place in the spec-
trum, extremely narrow fragments as it
were of the continuous spectrum, and sep-
arated by intervals, more or less wide, of
darkness -gaps where that spectrum has
This is strange, and
totally disappeared.
in its first impression strangely irregular:
but further examination shows us a yet
stranger regularity. There is no rule as to
the thickness or position or grouping of the
bright lines: but we shall find that every
chemical element, whatever its nature, has,
when in a state of vapour, a system of lines
of its own, and so peculiarly appropriate to
itself, that the appearance or non-appear-

of the presence or absence of that element.
It is true, this evidence is not in all cases
of ready attainment. Some materials stand
a great amount of violence, so to speak, in
refractory silence; but all have been found
to yield to the irresistible energy and sub-
tlety of electricity, that 'fervent heat,' per-
haps, as far as natural causes are concerned,
in which the elements shall hereafter melt
and pass away.

The terrestrial incandescence, thus vividly described, becomes a source of light independent of the sun, and capable of being examined as to its constitution with equal facility. The spectroscope, an instrument invented by the celebrated German optician Frauenhofer, and destined hereafter to take rank only after the tele-ance of those lines is an infallible criterion scope and the microscope as a revealer of mysteries, is the medium of investigation in either case. Its structure is sufficiently simple, comprising, as its essential parts for the details are subject to much variation-a slit of adjustable narrowness between two metallic plates, to eliminate the overlapping of the spectra; a prism, or rather, in order to obtain a wider dispersion, a combination of prisms, to decompose the admitted but straightened ray; But our investigation, however interestand a small telescope, the intention of which ing, does not thus far bring us to any conis to magnify the spectrum thus formed, clusion. We have been advancing apparand rendered sufficiently pure to exhibit its ently in parallel, in place of converging diinterior arrangement, so as to unfold more rections. The spectrum of the sun is diseffectually its complexity. The investiga- continuous, with hair-breadth tracks of darktion conducted by means of this beautifulness. The spectra of the terrestrial eleapparatus is known as spectrum analysis, and it is equally applicable to every kind and degree of light, provided it retains sufficient intensity, after this unsparing reduction and expansion, to form a distinct impression upon the eye.

Our next process, therefore, is to submit to examination the light given out by the terrestrial elements. These the chemist knows how to raise to incandescence in the hard-piled forge or crucible, the insidious

ments are also discontinuous, but with hairbreadth lines of light. The one seems of a class which is the reverse of the other. But this apparent contrariety will lead to further thought and further investigation. There may be more connection here than meets the eye. Their relative position might be collated. No one element has bright lines at all comparable in number to the dark bands of solar light: still, if any single elementary line-system were found

to agree in position throughout with a cor- of these bands? If this cannot be exresponding number of solar interstices, plained, the whole remains in a state of would it not be a marvellous coincidence? unpenetrated obscurity. Nothing but such The interruptions are so extremely minute a reversal by actual experiment could estabfor the most part, and so perfectly invaria- ablish their identity; and what could seem blei n relative situation, that if it were pos- less likely than such an experiment, to be sible to match, and fill up precisely, any devised, or to be successful? Yet it has one set out of them, would it not be a most been done. Even this has not been denied suspicious and suggestive fact? But this is to the patient enterprise of man. A single just what the ingenuity of man has been instance of such a change would have been permitted to do. The skill of the optician sufficient to establish the principle - but has brought the bands of the terrestrial el- it has been effected over and over again. ements successively into direct comparison And though we have not as yet accomwith the solar lines, placing them side by plished a general reversion of these lines side in the same field of view. In very and no wonder, the conditions of the exmany cases no correspondence can be found. periment being peculiarly embarrassingThe sets of objects are similar in character, yet we have lifted the veil in so many plabut so dissimilar in position and grouping ces, and with so varied elements, that no that there can be no mutual relation. reasonable doubt as to what lies behind it But in other instances we are startled by can remain: the difficulty experienced in the accord. In number, in position, in applying our scanty means of operation thickness, the correspondence is absolutely would not be felt for a moment in the gloperfect; every line of the terrestrial ele- rious laboratory in the centre of our system. ment has its fellow, somewhere or other, in The principle then is this: that when an the long and multitudinous series of the so- element in the state of vapour has been so lar bands. Strange coincidences, without heated as to give out its characteristic bright real connection, there certainly have been, bands, if the light of these bands subseand are, in the system of things. For ex-quently traverses another stratum of the ample, it once happened to the writer to same vapour, of a lower and non-luminous bring out, at the close of an arithmetical temperature, these bands will be reversed, operation, the succession of figures 12345.6, absorbed we might say, in their transit, the chances against which must have been and will appear no longer bright but dark, extremely great. But there is something if there is any luminous background capamore here. A possibility of course there ble of exhibiting them by contrast. must be in the abstract, that such a corre- then will this apply to the case before us? spondence might be the effect of chance: We shall be at no loss for the explanation, that is, since the lines must be of some defi- if we only suppose, first of all, that the real nite number and dimensions, and must oc- body, or more correctly, photosphere of the cupy some definite position, there cannot be sun consists of materials of such a nature any natural impossibility that the number as to stand the amazing temperature concenand dimensions and position in each case trated there, if not without fusion, yet withshould correspond. But the resources of out being reduced to vapour. Carbon, posmathematics enable us to compute the sibly, might answer the description, but the probabilities of such matters, and it is stated means of identification are wholly absent. that, with regard to one set of lines only, Such bodies would give us the continuous consisting of about 60 individuals, the spectrum the brilliant background of vachances in favour of that coincidence im-ried colours. These, in fact, are the real plying identity are as 1,000,000,000,000,000,000 to 1. And this, we must remember, though possibly the strongest, is yet but one out of a considerable number of similar instances, each increasing the chance against error in so high a ratio, that though not a mathematical, it becomes a moral impossibility; and we are forced to admit a connection of the most intimate nature between those sets of luminous terrestrial and the corresponding non-luminous solar lines. It is obvious, however, that a very important link is wanting. How are the light and darkness to be reconciled? What has wrought the apparent reversal of the state

How

source of the solar light, and these perhaps may constitute the great bulk of that huge luminous mass; but of their nature we are, and must remain, in ignorance, since, as far as our present means of investigation extend, it could only be manifested to us by those elementary lines, which are not otherwise called out except by commencing volatilisation. Among these unknown solid or fluid materials, however, are interspersed, we must suppose, a number of elements of a less refractory character-substances which resolve themselves into vapour in the focus of that unearthly glow, and float at a limited height above it. These would ob