Tasmania. Meanwhile, what's the use of an Aborigines Protection Society? They don't seem able to protect any. The Yankees, we are told, put sacredly aside the native reserves; but they take care that close to the reserve of one tribe shall be that of another which is decidedly hostile to the first. Hence the reserves speedily lapse for want of inhabitants. Canon Kingsley used to comfort himself by calling all these natives rotting races, created to perish away before the white man. It is a happy thing for us that the old Romans didn't have that opinion of the Germans and the Britons.

From The Spectator.
OXYGEN IN THE SUN.

its deviations are all limited to one plane, and the spark, as actually presented before the slit of the spectroscope, appears as a straight line. As with all these improve. ments, the coincidences remain as perfect as before, we may fairly admit that the evidence has been greatly strengthened, -not quite in the degree perhaps mentioned in the Times of Monday last (sixty-eight thousand seven hundred and twenty-five mil lionfold,) but still to a very noteworthy extent.

The

We do not wish to discuss here, however, the details of Dr. Draper's researches, but to consider some of the striking conclusions which his results appear to suggest. The view of the solar spectrum originally suggested by Kirchoff was simply this, that the glowing mass of the sun, whether consisting in the main of solid, liquid, or highly compressed NEARLY two years ago, we had occasion vaporous matter, shines with all the tints to consider in these columns Dr. H. Dra- of the rainbow, giving of itself a perfectly per's recognition of the bright lines of continuous spectrum; while the relatively oxygen in the spectrum of the sun. At cool vapors surrounding it absorb those that time, doubts were expressed as to the rays over which they have power (the rays validity of the evidence he had obtained. they absorb being in fact those which they Some even went so far as to assert that no are capable of emitting). Thus, the dark element in the sun can possibly show its lines, or missing tints, indicate the prespresence by bright lines, at least, not ence of an absorptive vaporous envelope, permanently. That hydrogen does so at exceedingly complex in structure. times is admitted; but that oxygen or any dark lines of hydrogen, sodium, magneother element should always do so, was sium, iron, calcium, and several other eleregarded as impossible. Yet there are ments were easily detected, and thus the stars as Gamma Cassiopeia, the middle presence of these elements in the gaseous star of the bright five which form the envelopes of the sun was recognized. straggling W or (in some aspects) M of But even now, with all the advances which that constellation in which the lines of spectroscopists have made, as well in the hydrogen are permanently bright; and one study of the solar spectrum as in the incan recognize no sufficient reason why the vestigation of the spectra of terrestrial elebands of oxygen in the solar spectrum ments, thousands of solar dark lines should not be also always bright. Others remain unidentified. In fact, with each considered the dispersive power of Dr. increase in the severity of the spectroDraper's instrument insufficient, though scopic scrutiny of the sun, the number of his enlarged photographs were on half the unidentified lines increases. When Kirc scale of Angström's well-known normal hoff first compared the spectrum of ironspectrum, and were on a larger scale than vapor with that of the sun, sixty iron lines the spectra from which Kirchoff had orig. were known, and all were found (as dark inally demonstrated the presence of hy- lines) in the solar spectrum. Now, nearly drogen, iron, sodium, magnesium, etc., in five hundred iron-lines are known, and all the sun. He has now removed this ob- are found in the solar spectrum. But the jection, however, by so increasing the same increase of power which has enabled power of his instrument as to obtain nega- spectroscopists to identify some four hun. tives as large as his former enlarged posi-dred new iron-lines in the solar spectrum, tives, and enlargements on such a scale has revealed many thousands of lines bethat the entire spectrum on the same scale fore unrecognized, and not a quarter of would be some eight or nine yards in these have been identified with the bright length. He has also purified his spectra, lines of terrestrial elements. by using what he calls a spark-compressor, taking the electric spark in air between two closely adjacent walls of soapstone, so that instead of being zig-zag in all directions,

But now the question arises whether the assumption that the bright background of the solar spectrum is a simple, continuous spectrum, a rainbow-tinted streak, such as

we get from a mass of metal at a white | mass were very dense at the centre, then heat, was admissible, or even whether it the observed absence of compression was not, on the whole, as improbable an would result as a necessary consequence. assumption as could have been made. Another line of evidence, pointing in the Have we reason to suppose that, apart same direction, is even more striking, from the vaporous envelope surrounding though some may not consider it equally what we call the sun-in other words, satisfactory. The study of the earth's that particular part of a far vaster object crust, and especially the careful compariwhich is limited by the bright surface of son between the present processes of dethe photosphere-it is constituted so sim- nudation and the observed traces of longply (as regards the condition of its multi- continued denudation in different parts of tudinous elements) as to give a simple, the earth, has shown that with the present continuous spectrum? Have we not, on amount of solar action (to which, of course, the contrary, most powerful reasons for all processes of denudation are primarily adopting an entirely different opinion? due), some hundred millions of years That vast orb, containing more than three would be required to have produced the hundred thousand times as much matter as observed features of the terrestrial strata. the earth, every part of which is acted on We are not necessarily bound to believe by centripetal forces far exceeding the that the sun has been at work for a hunforce of gravity at the earth's surface, has dred millions of years, causing rain and a mean density scarcely exceeding one- snow to fall on the earth, winds to blow fourth of the earth's. We cannot imagine over her surface, and in other ways causthat this small mean density is the same, ing processes of denudation. He may or nearly the same, as the density of the have worked far more actively in remote sun's central regions. The central por- times, and so have produced those effects tions must have a far greater density, the in much less time. But that does not outer portions, even to a depth of tens of affect our present argument, which relates thousands of miles below the visible sur- only to the work done by the sun, not to face, must have a far smaller density, than the time occupied by him in doing it. that mean density of the sun which yet Now we find that even if the sun's present very little exceeds the density of water. mass be supposed to have been originally We have, however, further evidence of a spread through infinite space, and thence very striking nature (as yet insufficiently gathered in to occupy the space he now considered by most astronomers) on this seems to occupy, in such sort, that is, as to point. It has been shown by Mr. G. H. form a globe of nearly uniform density Darwin that the sun, if of uniform or some eight hundred and fifty thousand nearly uniform density, should, at his miles in diameter, the solar radiation reactual rate of rotation, exhibit a compres- sulting from that process of contraction sion which, though small, ought not to would have only been equivalent to his have escaped the processes of measure- present rate of emission continued for ment constantly applied to the sun. It is twenty millions of years, and would thus true, the observations of the sun at Green- have fallen far short of the supplies of light wich and other national observatories are and heat which we know he has poured not applied with the object of detecting any upon the earth. Now, Croll gets over this compression of the solar globe, if such difficulty by the theory that part of the compression existed; but they are none sun's supply of light and heat was derived the less effective to that end. And it is from the velocities with which two or more certain that so utterly is all evidence of orbs came into collision to form the sun's compression wanting, that on one occa- present mass, a theory wild in the exsion, when a careful amateur observer treme. We might as reasonably explain thought he had detected such evidence, the astronomer-royal remarked (and justly) that the apparent recognition of solar compression from a limited series of observations could only demonstrate the inexact ness of the observations, so absolutely do the observations (practically unlimited in number) of professional astronomers demonstrate the absence of detectible compression. Now, Mr. Darwin further showed, by mathematical reasoning of a most satisfactory kind, that if the sun's

the small number of killed and wounded in a battle, by assuming that nine-tenths of the bullets encountered each other in midair between the two armies. But if we accept the evidence of the geologists, and there seems no way of escape in that direction, and if we admit, which also seems clear, that the bulk of the sun's radiation must be accounted for by processes of contraction which he has undergone in the past, then we arrive inevitably at the conclusion to which we have been already led

in other ways, that his central regions | His spectrum would thus come to be are far denser, his outer portions far rarer, regarded as compounded of many gaseous than his mass regarded as a whole. In spectra, forming a continuous but by no other words, the process of contraction means uniform background. And Dr. has gone much farther than had been sup- Draper's discovery would seem to show posed when the whole globe of the sun that oxygen forms so important a constituwas regarded as of nearly uniform density. ent of this deep gaseous envelope around Adopting the conclusion thus arrived at the real globe of the sun, as to give a by three independent lines of argument, spectrum standing out by its superior we perceive that the sun's mass must prob- brightness from the rest of that continuably be gaseous to a depth of many thou-ous background. sands of miles below the apparent surface.

The

IN PRAISE OF THE BLUE-bottle. animal is wanted for the special purpose of destroying carrion, so as to prevent its becom-ness on the wing. Bees are very properly ap ing a nuisance. The creature appropriate for this purpose is a small worm, known as a maggot. But how are such worms to be extemporized, when a mass of putrid meat is to be disposed of? The difficulty is beautifully got over by sending a particular kind of big fly called a blue-bottle, that is entitled to rank as a scavenger-general. Instinctively, the bluebottle discovers where its services are required. There it deposits eggs; the eggs very speedily become maggots, and the maggots make short work of eating up every scrap of the putrid mass. When that is done they cannot fly away. This, however, is provided for. They undergo a transformation into flies, and they set off in a flight for new substances requiring their attention. This is but a brief explanation of the process of transformation, which is various according to circumstances. It is sufficient to impress us with the fact that the creature referred to is in a sense two distinct animals. It has a flying life and a crawling life; or more correctly, while in its flying state, it can originate a host of crawling creatures admirably adapted for the design in view. In pursuing its professional avocations, the blue-bottle is far from being particular. It will as readily attack a joint of meat as a dead horse. Cooks, of course, have a detestation of blue-bottles, which they think are created only to torment them, and they would be glad to hear that they were exterminated off the face of the earth. This is being a little unreasonable. Blue-bottles have a right to live, if they can. No doubt, they make themselves very troublesome when by accident they find their way into a room, and keep buzzing on the window panes. On these occasions they are to be pitied. They are trying to get out, with a view of performing their proper functions, and they should be let out accordingly. | If they wish to go about their business, why not let them go by all means, and be thankful for the riddance? In short, though apt to be an annoyance, blue-bottles are sent for a good purpose. They have their appointed uses in creation, and for these uses, their structure,

An while not displeasing to the eye, is admirably
adapted. Look at their alacrity, their swift-
plauded for their industry. But we doubt if
they are a whit more industrious than blue-
bottles, for they are ever actively roaming
about to "improve each shining hour," on
their own proper mission, which is to remove
what is unwholesome and unsightly.
merits of blue-bottles have been a little over-
looked in literature. Heraldry has strangely
neglected them. Should the fraternity of
scavengers think of getting up a coat of arms,
they might with great propriety adopt the blue-
bottle as a crest. We know that cooks will
never be reconciled to blue-bottles. All they
have to do is to keep joints out of their reach.
Chambers' Journal.

DISTRIBUTION OF WORK TO A DISTANCE BY ELECTRICITY. Several experiments have lately been made in France in transmission of work by means of two Gramme machines, one made to produce electricity by mechanical work, the other to do the opposite and restore the work. Exact data of such an experiment at Sermaize (Marne) have been published by M. Tresca. There is a Gramme machine in the sugar-works there, driven by a steam-engine at the rate of twelve hundred revolutions in a minute. This was connected by a copper wire or cable with a Gramme machine on a carriage at four hundred mètres distance, and another Gramme machine two hundred and fifty mètres further away; a commutator on the first carriage allowed of directing the current to work either machine as required. These secondary machines were caused to actuate drums with cables wound round them whereby ploughs of the double Brabant type were drawn in a field. An effective force of three-horse power was thus obtained. The first Gramme actuated by the current made eleven hundred and twenty-three turns in the minute, the second eight hundred and ninety. The current could also be applied to move the carriages on which the Gramme machines were conveyed.

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