The Train, he makes nothing else but the Beams of the Sun, falling on the head of the Comet, and passing through the same, refracted and reflected. And amongst his Observations and Schemes of this Comet, there occurs one, wherein the Tail is curve, so seen by him Decemb. 11/21. He assigns the causes why the Trains do so much vary, and shews also, on what depends their length.
Whether the same Comet returns again, as the Spots in the Sun? and, whether in the time of great Conjunctions they are more easily generated? and whether they can be certainly foretold? with several other Inquiries, he refers for to his great Book.
As to Prognostications, he somewhat complains, That men do more inquire what Comets signifie, then what they are, or how they are generated and moved; professing himself to be of the mind of those that would have Comets rather admired then feared; there appearing indeed no cogent reason, why the Author of Nature may not intend them rather as Monitors of his Glory and Greatness, then of his Anger or Displeasure; especially seeing that some very diligent Men (among whom is Gemma Frisius) take notice of as great a number of good as bad Events, consequent to Comets. Seneca also relating, That that Comet which appeared in his time, was so happy, that it did Cometis detrahere infamiam, it cleared the credit of Comets, and made People have good thoughts of them.
Having given some Account of what may be look'd for in this Prodromus, it follows, That some also should be rendred of the Animadversions mention'd to have been made upon the same. This was done by that Parisian Philosopher Monsieur Auzout, in a Letter of his to his Country-man Monsieur Petit; in which he strongly conceives, That this
Prodromus contains some mistakes, of which he chiefly singles out one, as most considerable, in Hevelius's Observation of Feb. 8/18, and declares thereupon, That he, and several very intilligent Astronomers of France and Italy concurring with him therein, (whereas M. Hevelius to him seems to stand single, as to this particular) found by their Observations, That this Comet could not, on that day of February, be there where M. Hevelius placeth it, viz. In Prima Arietis; unless it be said, That it visited that Star of Aries on the 18, and returned thence the 19th, into its ordinary course; in which, according to his, and his several Correspondents Observations the Comet on Feb. 17. was distant from that first Star of Aries at least 1 degree and 17 minutes; and on February 19. (he having missed, as well as his other Friends, the Observation on Febr. 18) was advanced in its way 12 or 13 minutes, but yet distant from the said Star some minutes above a whole degree, and consequently far from having then passed it. After which time M. Auzout affirms to have seen it as well as several others, for many daies, and that until March 7/17, observing, That about Feb. 26. or 27, when the Comet was nearest to the often-mentioned first of Aries, it approached not nearer thereunto, then the distance of 50. minutes.
This important Difference between two very Learned, and very deserving Persons, being come to the knowledge of some of the ablest Philosophers & Astronomers of England, hath been by them thought worthy their Examination: and they being at this very present employed in the discussion thereof, by comparing what hath been done and published by the Dissenters, and by confronting with them their own Domestick Observations, are very likely to discern where the mistake lies; and having discern'd it, will certainly be found hightly impartial and ingenuous in giving their sense of the same.
Of the Mundus Subterraneus of Athanasius Kircher.
This long expected Subterraneous World, is now come to light, dedicated (at least the Exemplar, that hath been perused by the Publisher of these Papers, who hears, That other Copies bear Dedication to other Great Princes) both to the present Pope, as being esteemed by the author to have a part of his Apostolical Kingdom there; and to the Roman Emperor now Regent, who indeed in his Kingdom of Hungary, and in several Provinces of Germany, hath very many and very considerable things, worthy to be observed, under Ground.