324 EPOCHS IN THE HISTORY OF THE CONTEMPLATION OF 



to have been condensed from this vapour, and redissolved 

 into it again. ( 497 ) In his " new arid strange discourse 

 on long-haired stars/' he represented comets also (to which, 

 before the actual investigation of the elliptic orbits of the 

 planets, he attributed a rectilinear not a closed or re-entering 

 path), as formed from the " celestial air." He even added, 

 in accordance with the old fancies of spontaneous genera- 

 tion, that comets were formed " like the herbs which grow 

 without seed from the earth, and as fishes are produced 

 from salt water by generatio spontanea." 



More happy in his other cosmical anticipations, Kepler 

 adventured the following propositions : That the fixed stars 

 are all suns like our own, surrounded by planetary systems ; 

 that our sun is enveloped in an atmosphere which shews 

 itself as a white corona in total solar eclipses; that the 

 situation of our sun in the great island of the universe 

 to which it belongs is in the centre of the crowded ring of 

 stars which forms the Milky Way ; ( 498 ) that the sun ro- 

 tates round its axis as do the planets and the fixed stars 

 (this was before the discovery of the solar spots) ; that 

 satellites, like those which Galileo had discovered revolving 

 round Jupiter, would be discovered round Saturn (and round 

 Mars) ; and that in the much too large interval ( 499 ) be- 

 tween Mars and Jupiter, where we are now acquainted with 

 seven asteroids, (and also between Venus and Mercury), 

 there moved planets, which their small size rendered invi- 

 sible to the naked eye. Anticipatory annunciations of this 

 nature felicitous conjectures, which have been for the most 

 part realised by subsequent discoveries excited general 

 interest; while none of Kepler's cotemporaries, not even 

 Galileo, paid any just tribute of praise to the discovery of 



