PORTION OF THE COSMOS. THE PLACETS. 317 



her in cosmical relations of space. In a kind of poetic 

 rapture, he makes Venus, together with the Earth, play 

 "major," "Dur," when in aphelion, and "minor," "Moll," 

 in perihelion; and even says that the highest tone of 

 Jupiter and that of Venus must unite in the " Moll," or 

 " minor consonance." But, notwithstanding all these fre- 

 quently employed, and yet merely figurative or symbolical, 

 expressions, Kepler says distinctly " Jam soni in ccelo nulli 

 existunt, nee tarn turbulentus est motus, ut ex attritu aura 

 coelestis eliciatur stridor" (Harmonice Mundi, lib. v. cap. 

 4). Here, then, is again mention of the rare and serene 

 celestial air (aura coelestis). 



The comparison of the intervals between the planets, with 

 the regular solids which he considered ought to fit into 

 those intervals, had encouraged Kepler to extend his hypo- 

 theses even to the heaven of the fixed stars ( 517 ). On the 

 discovery of Ceres and of the other small planets, Kepler's 

 Pythagorean combinations were vividly recalled to recollec- 

 tion, on account of his previously almost forgotten expres- 

 sions respecting the probable existence of a yet unseen 

 planet in the great gap between Mars and Jupiter : (motus 

 semper distantiam pone sequi videtur : atque ubi magnus 

 hiatus erat inter orbes, erat et inter motus). 



In his Introduction to the Mysterium cosmographicum, 

 Kepler says " I have become bolder, and now place a new 

 planet between Jupiter and Mars, as well as" a less happy 

 hypothesis, and one which long remained unnoticed ( 518 ) 

 " another planet between Yenus and Mercury : probably it is 

 the extraordinary smallness of both which has caused them to 

 remain unseen" ( 519 ). Subsequently Kepler found that he did 

 not require these new planets for the arrangement of his solar 



