442 



Berlin astronomer had already distinctly declared, in the 

 second edition of his popular and extremely useful Anleitung 

 zur Kenntmss des gestimten Himmels, that " he had taken 

 the law of the distances from a translation of Bonnet's Con- 

 templation de la Nature, prepared by Professor Titius at 

 Wittenberg," still it has generally borne his name, and 

 seldom that of Professor Titius. In a note which the latter 

 added to the chapter on the System of the Universe, 81 he 

 says: " When the distances of the planets are examined, it 

 is found that they are almost all removed from each other by 

 distances which are in the same proportion as their magni- 

 tudes increase. If the distance from Saturn to the Sun is 

 taken as 100 parts, the distance of Mercury from the Sun is 

 4 such parts, that of Venus 4 + 3 = 7 such parts, the Earth 

 4 + 6 = 10, Mars 4 + 12 = 16. But from Mars to Jupiter 

 there is a deviation from this accurate (!) progression. Mars 

 is followed by a space of 4 + 24 = 28 such parts, in which 

 neither a principal planet nor a subordinate planet has yet 

 been seen. Is it possible that the Creator should have left 

 this space empty? It cannot be doubted that this space 

 belongs to yet undiscovered satellites of Mars ; or that per- 

 haps even Jupiter has further satellites around him, which 

 have not hitherto been seen by any telescope. In this space 

 (unknown to us as regards its contents) Jupiter's circle of 

 action extends to 4 -f 4S =z 52. Then follows Saturn in 

 4 + 96 = 100 parts an admirable proportion." Titius was 

 therefore inclined to consider the space between Mars and 

 Jupiter as containing, not one, but, as is actually the case, 

 several cosmical bodies; however, he conjectured that they 

 were more likely to be subordinate, than principal planets. 



11 Karl Bonnet, Betraclitung iiber die Natur, translated by 

 Titius, second edition, 1772, p. vii. note 2 (the first edition 

 appeared in 1766). In Bonnet's original work no such law 

 is noticed. (Compare also Bode, Anleit. zur Kenntniss des 

 gestirnten Himmels, second edition, 1772, p. 462.) 



