AND THEORY OF THE HEAVENS. 6 1 



instruments and the perfection of astronomy, give us well- 

 founded hopes for the discovery of such peculiar and 

 remarkable things. 1 The credibility of the fact itself, in 

 accordance with the principles of nature and analogy 

 which well support this hope, is such that they may 

 stimulate the attention of the explorer of nature so as to 

 bring about its realization. 



The Milky Way is, so to speak, the zodiac of new 

 stars which alternately show themselves and disappear, 

 almost only in that region of the heavens. If this 

 alteration of their visibility arises from their periodical 

 removal and approach to us, then it appears from the 

 systematic constitution of the stars here indicated, that 

 such a phenomenon must be seen for the most part only 

 in the region of the Milky Way. For as there are stars 

 which revolve in very elongated orbits around other fixed 

 stars like satellites around their planets, analogy with 

 our planetary world, in which only those heavenly bodies 

 that are near the common plane of the movements have 

 companions revolving round them, demands that those 

 stars only which are in the Milky Way will also have 

 suns revolving round them. 



I come now to that part of my theory which gives it 

 its greatest charm, by the sublime idea which it presents 

 of the plan of the creation. The train of thought which 

 has led me to it is short and natural; it consists of the 

 following ideas. If a system of fixed stars which are 

 related in their positions to a common plane, as we have 



1 De la Hire, in the Memoires of the Paris Academy of the year 

 1693, remarks that from his own observations, as well as from com- 

 parison of them with those of Ricciolus, he has perceived a marked 

 alteration in the positions of the stars of the Pleiades. 



