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of any ſuch Sight either from home or abroad; notwithſtanding that for above half that time, theſe Philoſophical Tranſactions have been a conſtant Regiſter of all ſuch extraordinary Occurrences. The firſt we find on our Books, was one of ſmall Continuance ſeen in Ireland by Mr. Neve on the 16th of November 1707 of which ſeen Phil. Tranſ. No. 320., And in the Miſcellanea Berolinenſia publiſhed in 1710, we learn that in the ſame Year 1707, both on the 24th of January and 18th of February, ſt. ver. ſomething of this kind was ſeen by M. Olaus Römer at Copenhagen: and again on the 23d of February, the ſame excellent Aſtronomer obſerved there ſuch another Appearence, but much more conſiderable; of which yet he only ſaw the Beginning, Clouds interpoſing. But the ſame was ſeen that Night by Mr. Gotfried Kirch, at Berlin above 200 Miles from Copenhagen, and laſted there till paſt Ten at Night. To theſe add another ſmall one of ſhort Duration, ſeen near London, a little before Midnight between the Ninth and Tenth of Auguſt 1708, by the Right Reverend Philip Lord Biſhop of Hereford, and by his Lordſhip communicated to the Royal Society: ſo that, it ſeems, in little more than eighteen Months this ſort of Light has been ſeen in the Sky, no leſs than five times; in the Years 1707 and 1708.
Hence we may reaſonably conclude that the Air, or Earth, or both, are ſometimes, though but ſeldom and with great Intervals, diſpoſed to produce this Phænomenon: for though it be probable that many times, when it happens, it may not be obſerved, as falling out in the Day-time, or in cloudy Weather, or bright Moon-ſhine: yet that it ſhould be ſo very often ſeen at ſome times and ſo ſeldom at others, is what cannot well be that way accounted for. Wherefore caſting about and conſidering what might be moſt probably the Material Canſe of theſe Appearances; what firſt occurr’d wasthe Vapour of Waterrarified
