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Yet once more, Baxendell of Manchester has proved that certain periodic meteorological phenomena, detected by him in the tabulated statements of the best observatories, can be explained by the theory that there exists around the Sun a ring or zone or spheroid of matter (his theory does not insist, he says, on any special form) at about that same distance from the Sun which Leverrier has assigned to the family of intra-mercurial planets.

Assuming that the meteoric families which undoubtedly exist, and undoubtedly become more densely aggregated with approach towards the Sun, do thus-as Leverrier's theory and Baxendell's would alike suggest -grow even yet richer at about that distance from the Sun to which the corona extends when most favourably seen, we have this also to further strengthen our belief in the resulting brightness of the solar appendage thus formed—that these meteors would be severally illuminated with inconceivable splendour on account of their nearness to the Sun. If we add to this that those approaching most nearly to him would be rendered incandescent, if not vaporised, by the intensity of his heat, and that most probably electric discharges would take place between them on account of the intense

I am aware that under ordinary terrestrial conditions the electric discharge will not take place through a vacuum. But we have no evidence that an actual vacuum exists where the corona is seen. On the contrary, it is probable that multitudes of the minute bodies travelling past the Sun become vaporised, and so combine to form a moving vaporous region, whose constituent parts are continually changing as fresh matter arrives and as portions pass away to distances where they

energy of the solar action, we have, I think, abundant reason for expecting that when the Sun undergoes eclipse an aureola of splendour would be seen around

him.

We have, then, two distinct lines of argument. We have been led by the consideration of the phenomena actually presented by the corona to the conclusion that multitudes of bodies too minute to be separately visible exist around the Sun; while we have been led by the consideration of what we know respecting multitudes of minute bodies actually travelling around the Sun to the conclusion that a corona or aureole of light would be seen around him during total eclipse. It seems clear, too, that all those peculiarities of the corona which have seemed to oppose themselves so obviously to other theories accord most perfectly with this. Save, perhaps, one only. If the corona is really crossed by radiating dark bars such as are shown in Mr. Gilman's picture, and described by several observers of total eclipses, then most certainly that phenomenon is not accounted for by the theory here put forward. The meteoric theory will account for a radial dark bar-by which I mean a bar directed in a straight line from the Sunas an occasional phenomenon. But that such bars should be a characteristic phenomenon of the corona, or that in any single case the corona should be seen

can resume their normal condition. Changes also occur, in all probability, which no physical researches yet made can explain, since we have proof of peculiar forms of action in the formation and rapid growth of cometary appendages.

streaked with several such bars, is a phenomenon which nothing in the meteoric theory considered per se is calculated to explain.

Now this is a difficulty which must be faced by some better means than a mere attempt to negative the evidence. That erroneous observations are made from time to time is unfortunately true; but when a characteristic phenomenon which does not seem likely to be merely imagined, is attested by trustworthy observers, a theory begins to wear a most questionable aspect which can only be supported by assigning those observations to illusion.

The difficulty in this case is that, even setting aside the objections (overwhelming as I think) which have been brought against all other theories but the meteoric one, we do not find in any of these theories the means of explaining this particular phenomenon.

Certainly no theory involving the existence of a lunar atmosphere can aid us in this strait; because if the radial bars were due to the passage of the solar rays straight through such an atmosphere in lines touching the Moon's edge (and no other path would account for the observed phenomenon), then the extension of the lunar atmosphere necessary to account for the observed appearances would be about 200,000 miles, or the lunar atmosphere would extend nearly to the Earth.* We cannot for a moment imagine this.

It is easy to see this by making a diagram showing the Moon and Earth, with the paths of the imagined rays extending along the boundary of the Moon's geometrical shadow, carrying the rays on until, as seen from the station of an observer on the Earth (and within the shadow. BB

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Nor again can the atmospheric glare' theory explain this phenomenon, unless we suppose the Earth's atmosphere to extend nearly to the Moon's distance,which is altogether incredible. Indeed, even if we admitted this, the bright rays between which the dark rays are seen ought to grow brighter and brighter with increase of apparent distance from the Moon, which is the reverse of what is actually seen.

It remains, then, that we should account for the phenomenon by the theory to which we have been led by other considerations. In fact, since the meteoric theory has been shown to accord so well with other phenomena, while it derives a negative strength from the obvious flaws in all the other theories, we are justified in accepting with a certain degree of confidence any explanation of these dark radial bars which the meteoric theory may point to. In other words, instead of feeling bound to explain these dark bars before admitting the meteoric theory, we may employ the meteoric theory to supply the explanation we require.

Now, there are two phenomena-one belonging to the solar system, the other to the Earth's economywhich seem likely to aid us in this matter. One is the appearance of comets' tails; the other is the aspect of auroral streamers. As respects the former phenomenon, it is to be remarked that the directive forces, whatever they may be, which cause the tails of comets

cone), they shall subtend an angle four or five times as great as that subtended by the Moon's diameter.

to project from the Sun, reside undoubtedly in the solar globe, and act undoubtedly with very great energy on certain forms of matter near him. Hence, as we have abundant reason for believing that the corona is not free from a certain association with cometary matter, we need not be altogether surprised if we find in the corona evidences of the same sort of action that we recognise in the formation and projection of comets' tails. Yet again, as respects the second phenomenon, we have the striking evidence afforded by the spectroscope to show that a resemblance of some sort exists between the coronal light and that of our auroras; so that we are justified in finding some resemblance, and even in conceiving that some association exists, between the long straight streamers which form so remarkable a feature of the aurora borealis, and those straight radial bars,* with dark intervening spaces, seen in the solar corona.

There is a circumstance which seems to render this relation more striking in the fact that the only explanation one can readily conceive of the observed characteristics of the auroral spectrum seems to bring us again upon that subject of meteoric astronomy which has thus far stood us in such useful stead. For

It is worthy of notice that a difficulty exists in the relatively small section of the radial bars, both bright and dark; for this phenomenon would imply that the centre of that action to which these bars are due cannot have the dimensions of the solar globe which we are able to measure. It seems far from unlikely (since indeed we have other evidence corroborating such a view) that the central and more condensed portions of the Sun's mass may be the real seat of this intense repulsive action.

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