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The abovementioned light at its extremities was unequally jagged, and scattered, an] followed the course of the westerly wind; so that for a few hours it spread considerably wider, yet without ever reaching the zenith. About the 6th hour of the night the in. tenseness of the colour disappeared; some small traces of the inflammation still remaining towards the north-east and the west, which were all vanished at 7{h, of the night.

The inflamed matter, in the greatest part of its extent, gave a free passage to the rays of the stars, even of the 3d and 4th magni. tude, situate behind it. About the 4th hour of the night, a very regular arch, of a parabolic figure, was seen to rise gently, to 2° of rectangular elevation, and to 20° of horizontal amplitude. This phenomenon was seen all over Italy, as appears by several accounts of it, though with some disagreement between them.

The most probable opinion as to the cause of this phenomenon, ascribes it to the simple firing of a bituminous and sulphurous mat. ter, on account of its very little specific gravity, raised to the upper parts of the atmosphere, and there, by the clashing of contrary winds, broken, comminuted, and at last set on fire. This opinion has been defended with strong arguments in the Petersburg Com. mentaries, by Mayer, on occasion of the appearance of a similar phenomenon in those northern countries. And indeed the pre. ceding eruption of Vesuvius, the contrariety of the moving forces, the readiness of the matter to take fire, the unequal intenseness of the light, the streaks, and all the other circumstances observed in this meteor, are plain arguments of a genuine and real ascension. And Wolfius, on the appearance of a phenomenon much like this, which was seen all over Germany, on the 17th of March, 1717, is of opinion, that it should be called imperfect lightning, as being produced by the inflammable matter of lightning.

Observed at Padua, by the Marquis Poleni, F.R.S. At the time of this meteor, the air was calm, aod the barometer was remarkably high.

At 5.b. there appeared near the horizon a blackish zone, with its upper limb of a sky.colour, somewhat obscure. Above this zone was another very luminous, resembling the dawn pretty far advanced. The highest zone was of a red fiery colour. The altitudes of the zones seemed to bear such proportion, that the second VOL, IV.

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was double the first, and the third triple ; and in many places they rose somewhat above the 40th degree of altitude. Eastward they extended to the 55th degree on the horizon, and westward to the 70th.

It is remarkable, that after sun set on the preceding days, as well as this, there appeared in the west a remarkable redness es. panded on each side; and on the ensuing evening, the same bright red colour, appearing near the horizon, deceived the common peo. ple into a belief, that a new phenomenon, like the foregoing, was breaking out of the horizon. Near our zenith there appeared some thin lucid clouds, partly of a whitish red, in such a manner, that they seemed as if occasioned by the burning of houses at some distance to the north. Others of this sort bad happened before, and some were seen afterwards.

A little after 6, the upper parts began to emit red streamings, or rays, in plenty ; but in these the red was now and then intermixed with whitish and darkish colours. In a few seconds after, there issued out from the very equinoctial west, a red and very bright column, which ascended to the third part of the heavens, and a little after, it became curved in the shape of the rainbow.

At half after 8, almost in an instant of time, the bright zone, from the 8th degree west to the 50th east, became more vivid, and rose higher; and above this appeared a new large one, of a red fiery colour, with several successive streamings tending upward, and passing 60 degrees of altitude ; the western part had assumed the form of a thin cloud. At twelve, the light of the aurora was nearly extinct, there appearing only a very weak light along the tops of the mountains. Twenty minutes after, there appeared a white brightish beam, at 30° west, and 60° high ; but it soon became invisible. In half an hour after, a very weak light remained in the west, near the horizon; which had not been observable, if the brightness of the preceding phenomenon had not invited to continue the observation. 3. Observed at the Obscrvatory of the Institute of Bononia.

By Dr. Eustachio Zanotti, Deputy Professor of Astronomy. The aurora borealis, which was formerly a rare phenomenon, and almost unknown in this climate, is now become very frequenta In Bonopia a great number have been observed for some years past.

This time it was so very remarkable, that no one remembers to have ever seen the like. As to its extent, it spread so as to occupy about 140° of the heavens; and, as to its light, it was so vivid, as by it to distinguish houses at a great distance; which seemed of a red colour, which made some people attribute this light to a fire in the neighbourhood.

It continued at times variously increasing and decreasing.

About 8, the aurora formed itself into a concave arch towards the horizon. The polar star was near the top of its convexity, and some stars shone bright in the midst of the light; and, among these, I and y of Ursa major. The concave part was terminated by a basis somewhat dark; which separated the red light of the arch from a white and very bright light that remained within it. The arch, which was 15° broad, was of a deeper colour towards the horizon than towards the pole. The western limit, which was in. terrupted by clouds, was wider and more irregular than the eastern limit. Fig. 2, pl. 10, exhibits the phenomenon conformable to the description now given.

About 8h. 34', the red light continued spreading, and made, as it were, a basis of a weaker redness. At this time the aurora appeared unsettled and curious, as in fig. 2. At its eastern limit, the pyramid continued visible, but of a more intense colour to. wards the north, and from its middle there shot up vertically a streak of light, between a white and a yellow colour. A very dark narrow cloud crossed the whole phenomenon, and went to terminate in the pyramid. At the upper part, a considerable tract of the heavens was enlightened with a very vivid red light, which was interrupted by several streaks or columns of a bright yellowish light. These streamings shot up vertically, and parallel to each other, and the narrow cloud seemed to serve them for a basis. Under the cloud there issued forth two tails of a wbitish light, hanging downward ou a basis of a weak red, and it seemed as if they kindled and darted the light downward. There was likewise seen a white streak, which passed across these two tails, and extended from one end of the phenomenon to the other, in a position alaost parallel to the abovementioned cloud.

At", 4m. there now remained but a little reddish light at the north pole. All the rest was collected near the 2 nith, not ex. tending lower than the star a of Ursa major. In the south, where 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 ap. peared 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.

3. 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 to. wards 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 liemisphere; 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, bat 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 heautiful 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 westem to the south. Its crown, or most elevated part, was not far from the zenith. The evening was clear, and the stars appear. ed 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 east. ern part of the hemisphere, and also a similar appearance in the opposite part of the heavens. These luminous parts, which appear.

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