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exhibited a very odd appearance; those on the right seeming sometimes to drive and push those on the left, and vice versa.

These are the principal phænomena; of whose causes I should have more willingly and with more certainty given my thoughts, if I had had the good luck to have seen the whole from beginning to end; and to have added my own remarks to the relations of others : and especially if we could by any means have come at their distances. If it shall by any be thought a bold supposition, that I assume the effluvia of the magnetical matter for this pur. pose, which in certain cases may themselves become luminous, or rather may sometimes carry with them out of the bowels of the earth a sort of atoms proper to produce light in the ether: I an. swer, that we are not as yet informed of any other kinds of efilu via of terrestrial matter which may serve for our purpose, than those we have here considered, viz. the magnetical atoms, and those of water highly rarefied into vapour. Nor do we find any thing like it in what we see of the celestial bodies, unless it be the effluvia projected out of the bodies of comets to a vast height, and which seem by a vis centrifuga to fly with an incredible swift. ness, the centres both of the sun and comet, and to go off into tails of a scarcely conceivable length. What may be the consti. tution of these cometical vapours, we the inhabitants of the earth can know but little, and only that they are evidently excited by the heat of the sun; whereas this meteor, if I may so call it, is seldom seen except in the polar regions of the world, and that most commonly in the winter months. But whatever may be the cause of it, if this be not, I have followed the old axiom of the schools, Entia non esse temere neque absque necessitate multis plicandu.

Lastly, I beg leave on this occasion to mention what, near 25 years since, I published in No. 195 of these Transactions, viz. That supposing the earth to be concave, with a less globe iucluded, in order to make that inner globe capable of being inhabited, there might not improbably be contained some luminous medium be. tween the balls, so as to make a perpetual day below. That very great tracts of the etherial space are occupied by such a shining medium, is evident from the instances given in the first paper of this Traosaction; and if such a medium should be thus inclosed within us; why may we not be allowed to suppose that some parts

of this lucid substance may, on very rare and extraordinary occa. sions, traosude through and penetrate the cortex of our earth, and being got loose may afford the matter of which this our me. teor consists. This seems favoured by one considerable circumstance, viz. that the earth, because of its diurnal rotation, being necessarily of the figure of a flat spheroid, the thickness of the cortex, in the polar parts of the globe, is considerably less than towards the equator; and therefore more likely to give passage to these vapours; whence a reason may be given why these lights are always seen in the north. But I desire to lay no more stress on this conceit than it will bear,

It having been noted that in the years 1575 and 1580, when this appearance was frequent, that it was seen not far from the lines of the two equinoxes; it may be worth while for the curious to bestow some attention on the heavens in the months of September and October next; and in case it should again happen, to endeavour to observe, by the method I have here laid down, what may de. termine, with some degree of exactness, its distance and height; without which we can scarcely come to any just conclusion.

[Phil. Trans. 1716.

SECTION III.

Observations on the Lumen Boreale, or Streaming, Oct, 8,

1726.

By the Rev. W. Derham, F.R.S. Tuene are two sorts of streamings, which have been noticed; one, by way of explosion from the horizon; the other, by open. ing and shutting, without shootings up, and swift dartings. Of the latter sort chiefly was that of October 8, 1726, in which, although the streams or spires, or lances, or cones, or whatever else they inay be called, were as large and remarkable as in the year 1715.6; yet they exhibited themselves principally by the vaporous matter opening and shutting, as if a curtain had been drawn and withdrawn before them. It began about eight o'clock, and soon streamed all round in the south, east and west, as much, or nearly as much, as in the north ; which was a thing not observed before in these phænomena.

These streams, or cones, were mostly pointed, and of different length, so as to make the appearance of flaming spires or pyramids; some again were truncatedl, and reached but half way: some had their points reaching up to the zenith, or near it, where they formed a sort of canopy, or thin cloud, sometimes red, sometimes brownish, some. times blazing as if on fire, and sometimes emitting streams all round it. This canopy was manifestly formed by the matter car. ried up by the streaming on all parts of the horizon. This some. times seemed to ascend with a force, as if impelled by the impetus of some explosive agent below, like that of March 1715.16. This forcible ascent of the streaming matter, gave a motion to the ca. nopy, sometimes a gyration, like that of a whirlwind; which was manifestly caused by the streams striking the outer parts of the canopy. But if it struck the canopy in the middle, all was then in confusion.

These two particulars, namely, the streaming all round, in all points of the horizon ; and the canopy in and near the zenith, are wliat were observed in all parts of England. But in the more southerly parts of Europe, it seems to have been somewhat different, by the accounts from different places.

One thing observed io most places was, that in some part of the greatest streaming, the vapours between the spires, or lances, were of a blood-red colour; which gave those parts of the atmosphere the appearance of blazing lances, and bloody-coloured pillars. There was also a strange commotion among the streams, as if some large cloud, or other body, was moving behind them, and disturbed them. In the northerly and southerly parts the streams were perpendicular to the horizon; but in the intermediate points they seemed to decline more or less one way or other; or rather to in. cline towards the meridian.

As for the cause of these phænomena, Mr. Derham takes it to be from the same matter, or vapours, which produce earthquakes : and that for these reasons : First, because some of these phæno. mena have been followed by earthquakes. As that which Stow gives an account of in his Annals, in the year 1574, on Nov.14; in which he says,

were seen in the air strange impressions of fire and smoke to proceed forth of a black cloud in the north towards the south. That the next night following, the heavens from all parts did seem to burn marvellous ragingly, and over our heads the flames from the horizon round about rising did meet, and there double and roll one in another, as if it had been in a clear fur. nace.” And after this, he says followed, on the 26th of February, great earthquakes in the cities of York, Worcester, Gloucester, Bristol, Hereford, and in the countries about, which caused the people to run out of their houses, for fear they should have fallen on their heads. In Tewksbury, Breedon, &c. the dishes fell from the cupboards, and the books in men’s studies from the shelves, &c.

So this last, in October, was preceded by that fatal carthquake at Palermo in Sicily, and succeeded by one in England, on Tues. day, October 25, following. This it seems was perceived in London, and was very considerable at Dorchester, Weymouth, Portland, Portsmouth, Purbeck, and several other places in Dorsetshire, that it caused the doors to fly open, shook down pewter off the shelves, and was felt in some ships that lay in the harbours.

Another reason is, that some gentlemen viewing this appearance, on the tops of their houses at Little Chelsea, plainly perceived a sulphurous smell in the air. Another thing which concurs with what has been said, is, that several persons heard a hissing, and in some places a crackling noise, in the time of the streaming, like what is reported to be often heard in earthquakes.

[Id. 1727

SECTION IV.

Collection of the Observations of the remarkable Red Lights shewn in the Air, Dec. 5, or 16, N.S. sent from different places to the Royal Society.

As observed at Naples by the Prince of Cassano, F.R.S. Dec. 16, 1737, N.S. in the evening, the sun being about 25 degrees below the horizon, a light was observed in the north, as if the air was on fire, and flashing; the intenseness of which gradually increasing, at the 3d hour of the night it spread much westward. Its greatest height was about 65°; for it occupied the whole extent of both the Bears and the polar star; yet at the sides it was not so high ; for in some places near the north it rose only to 50°, and it gradually diminished, so as to become insensible at the true horizon.

The abovementioord light at its extremities was unequally jagged, and scattered, and 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 20 of rectangular elevation, and to 20° of horizontal amplitude. This phenomenon was seen all over Italy, as appears by several ac. counts 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 mata 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 h. 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 colouar. The altis tudes of the zones seemed to bear such proportiori, that the second

VOL. IV.

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