tions matter is ejected with a velocity fully equal to the requirements of the eruption theory of the corona. The only question, then, which remains is whether along with, or in front of, the uprushing hydrogen, some solid, liquid, or at least very dense matter, is expelled in these stupendous eruptions-such matter retaining a much larger proportion of its velocity, because much less effectually resisted by the solar atmosphere than hydrogen, the rarest of all known gases. On this point we have no direct evidence; but we have indirect evidence of such a character as to leave little room for any doubt. Much evidence of this sort has already been given in the earlier part of the present essay and in the preceding paper. There is yet other evidence; but this evidence is not such as can be suitably presented at the close of a paper already drawn beyond the limits proposed when it was commenced. For the present, then, I must remain content with having presented the evidence recently obtained respecting the nature of solar eruptions—as respects the regions where they chiefly occur, the features which distinguish the prominences to which they give birth, and the enormous velocities with which the erupted matter travels when close by the solar surface. Viewed in connection with the eruption theory of the corona, the facts here adduced amount very nearly to a demonstration; but apart from all reference to theoretical considerations they possess an exceeding interest, in so far as they bear on our ideas respecting the physical habitudes of the great luminary which rules the planetary system. COLOURS OF THE DOUBLE STARS. 6 OLD ZAHN, in the strange work called the Syntagma,' says of the stars that they shine 'more like torches burning with eternal flame before the altar of the Most High, than the lamps of the ethereal vault, or the funeral lights of the setting sun.' And he proceeds to discuss the various colours seen among the stars, arguing that the stars show by their tint to which planetary party they belong. There are the partisans of Saturn, with a dull and leaden aspect; the Jovial stars brilliantly white; and the Martial party with fiery, ruddy rays. Those stars which have an orangecoloured light are the adherents, he thought, of our sun; while those which are pale and faint belong to the moon. Lastly, the stars which obey the planet of Love, shine with a box-coloured light! One cannot wonder that even before its true significance was understood, a phenomenon so beautiful as the coloured splendours of the stars should have attracted attention. In our latitudes, indeed, the colours of the stars are not very striking, though even here they may be very easily recognised when the air is clear and dry. But in southern climes, and especially in the land where astronomy had its birth, the colours of the stars form a very beautiful feature of the nocturnal heavens. The whole sky,' remarks a modern traveller, 'seems set with thousands of varied gems.' Nay, even the shooting-star, as it flashes across the heavens, exhibits colours which are never seen in our latitudes. Sir Alexander Burnes remarks on the magnificent spectacle presented by the coloured shooting-stars seen from the elevated table-land of Bokhara, and Humboldt was deeply impressed by the same beautiful phenomenon. The colours, then, which we notice in the stars are to be looked upon as giving but the faintest notion of the real splendour of the hues with which those distant suns are shining. If the mere change from our latitudes to tropical climes can add so much to the brilliancy of the stellar colours, how gorgeous would be the scene if we could behold the galaxy of suns from above the limits of our own obscuring atmosphere! We should see Arcturus and Aldebaran, Pollux, Antares, and Betelgeux blazing like sun-lit rubies among their fainter neighbours; the glorious yellow of Capella and Procyon would surpass the most splendid golden or topaz colours known to our artists; while the brilliant white hues of Vega and Altair and the blazing Sirius would be no less beautiful and striking. But even such a scene as this, wonderful as it would appear, would be as nothing when compared with the splendours which would come into view if the powers of the observer's vision could be gradually increased until the stars, which are now only detected by the piercing eye of the telescope, were seen in all the richness and variety of their colours. It is among the stars which are invisible to the unaided eye that the real splendours of celestial colouring are to be found. No words can adequately describe the beauty of the scene which our observer would behold; but if he sought to convey some imperfect notion of the glories revealed to him, he could find perhaps no apter account than the well-known lines of Thomson : First the flaming red Sprang vivid forth; the tawny orange next, In this order would the colours of the stars come into view. We see in the nocturnal skies no traces of those green and violet and blue and purple suns which are really pouring forth their richly-tinted rays on other worlds and other scenes. Only the ruddier tints of the prismatic colour-scale are visible to the unaided eye, and even these not with that fulness or depth of tone which may be recognised in the telescopic stars. But even among the stars which the telescope reveals to us, the full range of colour is only to be seen among the members of a peculiar order. There is a little difference among astronomers on this point; but most of them agree that no isolated stars of a blue, or green, or purple colour can be seen even with powerful telescopes. So commonly has this been asserted, that the late Admiral Smyth, who thought he could recognise very decided blue tints among the minuter stars, expressed a doubt whether this might not be due to some idiosyncrasy of his eyesight. And certainly there is no instance, among the thousands on thousands of stars whose places have been recorded, of one isolated star of a well-marked blue colour. But when we turn to those interesting objects, the double stars, the scene is wholly changed. Every variety of colour is seen among these singular systems. We not only find all the tints of the rainbow, but a number of other colours, such as fawn, buff, ashcolour, silvery white, coppery, and grey. The range of colour seems, in fact, wholly unlimited; and astronomers need the aid of a practical artist before they can even tabulate the long list of colours which the double stars exhibit to them. There are few subjects which seem better calculated to attract and interest even the least thoughtful than the presence of these singularly beautiful colours among the orbs of heaven. Regarding the fixed stars as suns, the centres of schemes of dependent worlds resembling in many respects the worlds which circle around our sun, we cannot but look with wonder upon the strange scene which must be presented amid those distant |