during eclipses. The following six pictures represent in order the work of the Astronomer-Royal, Mr. Dawes, Mr. Hind, Mr. Lassell, Mr. Gray, and Mr. Stephenson. Mr. Airy thus writes respecting the prominences:

'The form of the prominences was most remarkable. That which I have marked a (fig. 58) reminded me of

The coloured prominences seen during the eclipse of 1851.

a boomerang. Its colour for at least two-thirds of its breadth-from the convexity towards the concavitywas full lake-red; the remainder was nearly white. The most brilliant part of it was the swell farthest from the Moon's limb; this was distinctly seen by myself and my friends with the naked eye. I did not measure its height; but judging generally by its proportion to the Moon's diameter, it must have been three minutes This estimation perhaps belongs to a later

of arc.

period of the eclipse. The prominence b was a pale white semicircle based on the Moon's limb. That marked c was a red detached cloud or balloon of nearly circular form, separated from the Moon's limb by a space differing in no way from the rest of the corona of nearly its own breadth. That marked d was a small triangular, or conical, red mountain, perhaps a little white in the interior. These were the appearances seen instantly after the formation of the totality. I employed myself in an attempt to delineate roughly the appearances on the western limb, and I took a hasty view of the country; I then remarked the Moon a second time. I believe (but I did not carefully remark) that the prominences a b c had increased in height; but d had now disappeared, and a new one, e, had risen up. It was impossible to see this change without feeling the conviction that the prominences belonged to the Sun, and not to the Moon. I again looked round, when I saw a scene of unexpected beauty. I went to my telescope with a hope that I might be able to make the polarization observations, when I saw that the sierra, or rugged line of projections shown at f, had arisen. The sierra was more brilliant than the other prominences, and its colour was nearly scarlet. haps increased in height, but no additional new ones had arisen. The appearance of the sierra nearly in the place where I had expected the appearance of the Sun warned me not now to attempt any other

The other prominences had per

physical observations. In a short time the white Sun burst forth, and the corona and every prominence vanished.'

Mr. Hind's narrative is as follows:- On first viewing the Sun without the dark glass after the commencement of totality, three rose-coloured prominences immediately caught my eye, and others were seen a few seconds later. The largest and most remarkable of them (a in Mr. Airy's drawing) was straight through two-thirds of its length, but curved like a sabre near the extremity, the concave edge being towards the horizon. The edges were of a full rosecolour, the central parts paler, though still pink. Twenty seconds, or thereabouts, after the disappearance of the Sun, I estimated its length at forty-five seconds of arc, and on attentively watching it towards the end of totality I saw it materially lengthened—probably to two minutes-the Moon having apparently left more and more of it visible as she travelled across the Sun. It was always curved, and I did not remark any change of form, nor the slightest motion during the time the Sun was hidden. I saw this extraordinary prominence four seconds after the end of totality, but at this time it appeared detached from the Sun's limb, the strong white light of the corona intervening between the limb and the base of the prominence. About ten degrees south of the above object I saw during the totality a detached triangular spot of the same rose-colour, suspended, as it were, in the light of the corona, which

gradually receded from the Moon's dark limb, as she moved onwards, and was therefore clearly connected with the Sun. Its form and position with respect to the large prominence continued exactly the same so long as I observed it. On the south limb of the Moon appeared a long range of rose-coloured flames, which seemed to be affected with a tremulous motion, though not to any great extent. The bright rose-red of the tops of these projections gradually faded towards their bases, and along the Moon's limb appeared a bright narrow line of a deep violet tint; not far from the western extremity of this long range of red flames was an isolated prominence, about forty seconds in altitude, and another of similar size and form at an angle of 145° from the north towards the east.'

I may add Mr. Dawes' account of the great prominence marked a in Mr. Airy's picture (fig. 58). A red protuberance of vivid brightness and very deep tint, arose to a height perhaps 14 when first seen, and increased in length to 2′ or more, as the Moon's progress revealed it more completely. In shape it somewhat resembled a Turkish scimitar, the northern edge being convex, and the southern concave. Towards the apex it bent suddenly to the south, or upwards, as seen in the telescope. Its northern edge was well defined, and of a deeper colour than the rest, especially towards its base. I should call it a rich carmine. The southern edge was less distinctly defined, and decidedly paler. It gave me the impression of a somewhat conical protuberance, partly hidden on its

southern side by some intervening substance of a soft or flocculent character. The apex of this protuberance was paler than the base, and of a purplish tinge, and it certainly had a flickering motion. Its base was, from first to last, sharply bounded by the edge of the Moon. To my great astonishment, this marvellous object continued visible for about five seconds, as nearly as I could judge, after the Sun began to reappear, which took place many degrees to the south of the situation it occupied on the Moon's circumference. It then rapidly faded away, but it did not vanish instantaneously. From its extraordinary size, curious form, deep colour, and vivid brightness, this protuberance absorbed much of my attention; and I am therefore unable to state precisely what changes occurred in the other phenomena towards the end of the total obscuration.'

Such are a few of the records of the appearance presented by the prominences during the eclipse of 1851. It would have been easy to have filled forty or

* The evidence of Mr. Dawes is very valuable, on account of his exceptional powers of vision. Probably he has never been surpassed in this respect. It may therefore be regarded as fortunate that he addressed his sole attention to one prominence; since some of the facts he detected are such as no later observations could have more satisfactorily established. Such, for instance, is his observation of the flickering motion of the upper part of the prominence. He was too well accustomed to recognise the apparent motions produced by our own atmosphere to be deceived into inferring real motion where none existed. His observation of the visibility of the prominence for several seconds after the Sun's reappearance confirms Mr. Hind's, and the fact is one of extreme importance, as tending to afford a measure of the luminosity of the larger prominences.