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the sky was clear, there were seen some of those meteors, called falling stars.

Several persons have positively asserted, that, in the evening of the 16th day, they perceived a certain stench in the air, like that which is sometimes occasioned by a fog. The same has been taken notice of at other times, when such phænomena have appeared.

There was a very thin fog in the air not only on the 16th day, but also on the preceding and ensuing days. The mornings of the 17th and 18th, before and a little after sun rise, the air appeared of an uncommon fiery colour. The evening of the 17th, the crepusculum was of an extraordinary height. Between the north and west, there was seen a very thin red vapour, which lasted almost till night.

4. Observed at Rome, by S. de Revillas, Math. Prof. & F.R.S. These observations are similar to the foregoing.

5. By Mr. James Short, at Edinburgh.

We were surprised, on looking out of the windows, about six o'clock, to find the sky as it were, ail in a flame; but on further inquiry, it was nothing but the aurora borealis, composed of red light. There was an arch of this red light reached from the west, over the zenith, to the east; the northern border of this light was tinged with somewhat of a blue colour. This aurora did not first form in the north, and after forming an arch there, rise towards the zenith, as they commonly use to do; neither did the light shiver, and by sudden jirks spread itself over the hemisphere, as is common; but gradually and gently stole along the face of the sky, till it had covered the whole hemisphere; which alarmed the vulgar, and was indeed a strange sight. A great circle of this light came from the west to the zenith, which seemed to be the magazine whence all the rest were supplied. It is but about a year since Mr. S. first observed this red light in the aurora bo realis, and only then in very small quantities.

6. At Rosehill, Sussex, by John Fuller, Esq. jun. F.R.S. It was a strong and very steady light, nearly of the colour of red ochre. It did not seem to dart or flash at all, but continued going on in a steady course against the wind, which blew fresh from the south-west. It began about north north-west, in form

of a pillar of light, at about 6h. 15m. in the evening; in about ten minutes, a fourth part of it divided from the rest, and never joined again; in ten minutes more it described an arch, but did not join at top; exactly at seven, it formed a bow, and soon after quite disappeared. It was all the while lightest and reddest at the horizon. It gave as much light as a full moon.

At 8, it began exactly north; it was very light then, but not near so light as before: in half an hour it made an arch from east to west, and went quite away to the south, when it ended muck with the same appearance as it began in the north, but not quite so red.

SECTION V.

Account of Luminous Arches.

By Mr. William Hey, of Leeds, F. R. S.

WHILE Mr. Hey was at Buxton, in March, 1774, about half-past eight, he saw a luminous arch, which appeared very beautiful in the atmosphere. Its colour was white, inclining to the yellow; its breadth in the crown apparently equal to that of the rainbow. As it approached the horizon, each leg of the arch became gradu. ally broader. It was stationary while he viewed it, and free from any sensible corruscations. Its direction seemed to be from about the N.E. to the S.W. at least its eastern leg was inclined to the north, and its western to the south. Its crown, or most elevated part, was not far from the zenith. The evening was clear, and the stars appeared bright. It continued about half an hour after it was first ob. served by the company.

In October, 1775, he saw a similar arch at Leeds, of the same colour, breadth, and position. It began to disappear in five or six minutes after he had discovered it, without changing its situation. The manner in which it vanished was quite irregular; large patches in different parts, and of different dimensions, ceasing to be luminous, till the whole had disappeared. The evening was rather cloudy.

In the evening of March 21, 1783, between eight and nine o'clock, Mr. H. observed something like a bright cloud in the eastern part of the hemisphere, and also a similar appearance in the opposite part of the heavens. These luminous parts, which appear.

ed in the eastern and western parts of the horizon, were connected by an arch of a fainter light.

It reached the horizon in the W.S.W. point. In its course it passed about 12° to the south of the zenith. Its breadth was about 9 or 10. It remained visible about ten or twelve minutes after he first discovered it, and then vanished gradually and irregularly. He observed no corruscations, nor any motion in this arch. A few minutes after another, and still more beautiful, arch made its ap. pearance. It arose a point or two nearer the N. E. than the former had done. Its southern edge passed up a little to the north of the tail of the Great Bear, which was then in a vertical position. Its northern edge appeared at first a little to the south of the polar star; but, during the continuance of the phenomenon, it gradually receded about 10° to the south. The arch descended about the W. N.W.; but neither the eastern nor western extremities reached the horizon; each of them ending in a point gradually formed a little above the horizon. This arch might be about 10 or 12° at its vertex. It continued visible for half an hour; and though he could not discover any corruscations, or quick motion, in any part, yet the different portions of it were perpetually varying in the density of their light, and the whole arch, or at least its vertex, made a slow and equitable motion towards the south. Where the light was the most dense, the smaller stars were rendered invisible by the arch, but stars of the second magnitude were not totally eclipsed by it. This arch disappeared, as the former, by patches; the light gradually becoming less intense. The colour of both these arches was white. Before the latter arch had entirely disappeared, a small one, not quite so broad as the rainbow, arose from its eastern leg, and ascending in a curvilineal direction to the polar star, terminated there. Its light was more faint than that of the other two arches; and it continued visible about a quarter of an hour. The evening was very fine when he saw these beautiful phænomena; the stars were bright, and there was not a cloud to be seen except in the horizon. There was a steady light in the north, without the least corruscation, extending from the N. E. to N.W. The wind blew from the N. E.

March 26, about the same time in the evening, Mr. H. was entertained with a similar appearance. He first observed two or

three columns of aurora borealis shooting upwards in the north; and in a short time after a complete arch, like those already de scribed, though somewhat different in its position. It arose between the E. and N. and N. E. points, passed obliquely to the south below Arcturus, and descended in the west through Orion, having almost the same direction through that constellation which the equator has. Its light was the most faint about the vertex of the arch. Its most dense parts were continually varying in the intensity of their light. The larger stars were visible through its densest parts. It varied its position, and it continued visible about half an hour; but there was nothing which could be called a shoot. ing, or quick corruscation. There was a steady northern light all the evening, or at least till the arch had disappeared.

The grandest specimen of this phenomenon which Mr. H. had seen, appeared on the 12th of April, between nine and ten in the evening. He perceived a broad arch of a bright pale yellow, arising between Arcturus and Lyra, about the right leg of Hercules, and passing considerably to the south of the zenith, its northern border being a little south of Pollux, and descending to the horizon near Orion, which was then setting. This arch seemed to be about 15° in breadth, and was of such a varied density, that it appeared to consist of small columns of light, which had a sensible motion. After above ten minutes he saw innumerable bright corruscations, shooting out at right angles from its northern edge, which was concave, and elongating themselves more and more till they had nearly reached the northern horizon. As they descended, their extremi. ties were tipped with an elegant crimson, such as is produced by the electric spark in an exhausted tube. After some time this aurora borealis ceased from shooting, and formed a range of beauti ful yellow clouds, extending horizontally about a quarter of a circle. The greatest part of the aurora borealis which darted from this arch towards the north, as well as the cloud-like and more stationary aurora, were so dense that they hid the stars from view. The moon was eleven days old, and shone bright during this scene, but did not eclipse the brightness of these corruscations. The wind was at north, or a little inclined to the east.

The last phenomenon of this kind which Mr. H. saw, was on the 26th of April. About a quarter before ten in the evening, he

observed in the W. a luminous appearance, of the colour of the most common aurora borealis. From this mass or broad column of light issued three luminous arches, each of which made a different angle with the horizon. That nearest to the south seemed to arise at right angles with the horizon; while that nearest to the north made the smallest angle, and passed towards the N. E. through the constellation Auriga, having Capella close to its upper edge. He had not viewed them many minutes when they were rendered invisible by a general blaze of aurora borealis, which possessed the space just before occupied by these arches. He was soon satisfied that where the aurora borealis was dense, it entirely hid from view the stars of the second magnitude. He observed this particularly with respect to the star ß in the left shoulder of Auriga. But the corruscations were never so dense as to render Capella invisible. The wind was between the N. and N. E. this evening.

After comparing the phænomena above described with each other, and with those observed by Mr. Cavallo, in London; by Mr. Swinton, at Oxford; by Dr. Huxham, at Plymouth; and by Mr. Sparshal, at Wells, in Norfolk; Mr. H. cannot entertain a doubt, that these arches had all the same origin; and that they ought to be considered as a species of that kind of meteor called aurora borealis.

[Phil. Trans, Abr. Vol. xvi, year 1790.

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