Page:Philosophical Transactions - Volume 029.djvu/423

 was ſcarce to be believed, ſeeming not inferiour to that of Lightning; and exhibiting, as it paſt on, a ſort of momentaneous Nubecula, which diſcovered it ſelf by a very diluted and faint Whiteneſs; and was no ſooner: formed, but before the Eye could well take ‘it, it was gone, aid left no Signs behind it. Nor was this a ſingle. appearance; but for ſeveral Minutes that we regarded: it, about ſix or ſeven times in a Minute, the ſame was again and again repeated; theſe Waves of Vapour (if I may be allowed to uſe the Word) regularly ſucceeding one another, and, as we gueſt, at intervals very nearly equal; all of them in their Aſcent producing a like tranſient Nubecula.

By this particular we were firſt aſſured, that the Vapour we ſaw, whatever it were, became conſpicuous by its own proper Light, without help of the Suns Beams: for theſe Nubecula did not diſcover themſelves in any other part of their paſſage, but only between the South-Eaſt, and South, where being oppoſite to the Sun they were deepeſt immerſt in the Cone of the Earths Shadow; nor were they viſible before or after. Whereas the contrary muſt have happened, had they borrowed their Light from the Sun.

We then made all the haſt we could to a place where there is a free Proſpect of the Northern Horizon. Being come there, net much paſt Ten of the Clock, we found, on the Weſtern Side, viz. between the W. and N. W. the Repreſentation of a very bright Twilight, contiguous to the Horizon; out of which there aroſe very long Beams of Light, not exactly erect toward the Vertex, but ſomething declining to the South, which aſcending by a quick and undulating Motion to a conſiderable Height, vaniſhed in a little time, whilſt others, tho’ at uncertain intervals, ſupply’d their Place, But at the ſame time through all the reſt of the Northern Horizon, viz, from the North