VOL. XXIX.] PHILOSOPHICAL TRANSACTIONS. 'ilQ 



by the testimony of Stow, on the 7th of October 1564. And from foreign 

 authors we learn, that in the year 1575 the same was twice repeated in Brabant, 

 viz. on the 13th of Feb. and 28th of Sept.; and seen and described by Cor- 

 nelius Gemma, professor of medicine in the university of Lovain, and son of 

 Gemma Frisius the mathematician. In a discourse he wrote on the prodigies 

 of those times, after several ill-boding prognostics, he thus very properly de- 

 scribes the cupola and corona he saw in the Chasma, as he calls it, of February. 

 " A little after, says he, spears and new flames arising, the sky seemed to be 

 all on a flame, from the north quite up to the zenith ; and at last, the face of 

 the sky was, for a whole hour together, changed into the uncommon form of 

 a dice-box, the blue and white changing alternately, with no less swiftness 

 and vertiginous motion than the sun beams do, when reflected from a mirror." 



Here it is not a little remarkable, that all these four already mentioned fell 

 exactly on the same age of the moon, viz. about two days after the change. 



As to the other of September in the same year 1575, Gemma writes; " The 

 form of the Chasma, of the 28th of Sept. following, immediately after sun- 

 set, was indeed, less dreadful, but still more confused and various ; for, in it, 

 were seen a great many bright arches, out of which gradually issued spears, 

 cities with towers and men in battle array ; after that, there were excursions of 

 rays every way, waves of clouds and battles; mutually pursued and fled, and 

 wheeling round in a surprising manner." From hence it is manifest that this 

 phenomenon appeared in our neighbourhood three several times, and that with 

 considerable intervals, within the compass of one year; though our English 

 historians have not recorded the two latter; nor did Gemma see that of Nov. 

 1574, probably by reason of clouds. After this, in the year 1580, we have 

 the authority of Michael Moestlin, (himself a good astronomer, and still more 

 famous for having had the honour to be the great Kepler's tutor in the sciences) 

 in his book de Cometa 1580, that at Baknang in the country of Wirtemburg 

 in Germany, these chasmata, as he likewise stiles them, were seen by himself 

 no less than 7 times within the space of 12 months. The first and most con- 

 siderable of these, was on the very same day of the month with ours, viz. on 

 Sunday the 6th of March, and was attended with much the same circumstances. 

 And again, the same things were seen in a very extraordinary manner on the 

 Qth of April and 10th of Sept. following: but in a less degree, on the 6th 

 of April, 21st of Sept. 26th of Dec. and l6th of Feb. 1581: the last of 

 which, and that of the 21st of Sept. must needs have been more considerable 

 than they then appeared, because the moon being near the full, necessarily 

 effaced all the fainter lights. Of all these however no one is mentioned in our 



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