Naturall philosophie reformed by divine light, or, A synopsis of physicks by J.A. Comenius ... ; with a briefe appendix touching the diseases of the body, mind, and soul, with their generall remedies, by the same author.

Of Comets.

XX Comets are accessory stars, which som∣times shine, and go out again: for the most part with tayles, or busbes of hair.

We reckon them to the heaven and stars, not to the air and meteors: because they are not generated in sublunary places, (as Ari∣stotle thought) but in the highest Heaven, even above the Sun: which 1 Their moti∣on, swifter always then the Moon it selfe. 2 Their parallax, lesse then the Moons, som∣times none at all, do shew.

XXI Comets are not vapours kindled; but a reflexion of the Suns light, in vapours so far elevated.

The first is easily proved. For if a Co∣met were a vapour kindled, it could not last halfe an hour. (For nothing can be kin∣dled but a sulphury matter, but that is con∣sumed in a moment, as it appears in Gun-powder, Lightning, a Chasme, a falling star, &c.) but histories relate that comets have lasted three years. The second is shewed, because comets 1 Cast a taile from the Sun, as the Moon doth a shadow; (for those dry vapours are not an opacous body, like to the Moon, but semidiaphanous.) 2 They are eclipsed (as Campanella testifies) by the shadow of the earth, as well as the Moon: which vvould not be, if they bur∣ned with their own fire.

N. W. That which is reported of a ful∣phureous matter, or stone, which fell from a burning comet, if it be true, it is to be thought, that it was made of some fiery meteors, not of a comet.

XXII The ends of comets are, that it may appear; 1 That the whole heaven moves, not the stars only. 2 That it is liquid and trans∣meable, not hard like Chrystall. 3 That va∣pours ascend so high, and that there are muta∣tions every where in this visible world.

Vapours, I say, whether exhaling from

this our inferiour world, or from the super∣celestiall waters. For there is nothing to the contrary, why we should not hold, that they also exhale, and are spread abroad in∣to the thinner region of the stars.