346 SCIENTIFIC RECORD FOR 1885. . 



pothesis. It also throws light on the cause of the observed distribu- 

 tion of satellites in the solar system. It is, in Professor Darwin's opin- 

 ion, a factor which cannot be left out of account, and has a bearing 

 on theories of evolution which cannot be neglected. Professor Darwin's 

 paper concludes with a summary of the advantages and disadvantages 

 of M. Faye's scheme. The conception of the growth of planetary bodies 

 by the aggregation of meteorites is a good one, and perhaps more prob- 

 able than the hypothesis that the whole solar system was gaseous. The 

 internal aunulation of the meteorites is left unexplained, and this com- 

 pares very unfavorably with Laplace's system, where the aunulation is 

 the very thing explained. The diflference of orbital motion of the inner 

 and outer meteorites of a ring, the development of that difference as time 

 progresses, and the consequence of direct and retrograde rotation at dif- 

 ferent distances from the sun, is an excellent idea. But it is necessary 

 to this idea that the inner planets should have been formed firet,* and 

 we are met directly by the fact that the single surviving ring, that of 

 Saturn, is nearer to the planet than are the satellites, and we should be 

 driven to the startling conclusion that Saturn's ring is the oldest feature 

 of his system. The actual distribution of satellites in the solar system 

 is at variance with M. Faye's theory, for as, according to him, the internal 

 planets were generated from rings whose motion was such as would give 

 greater moment of momentum to the planetary agglomeration than would 

 the external ones, the number of satellites should be greater the greater 

 the amount of rotation in the primitive agglomeration of meteorites, and 

 thus the nearer planets should be richer in satellites than the remote 

 ones. On the whole, then, there are great difficulties in the acceptance 

 of INI. Faye's scheme, notwithstanding its excellences; but science is un- ^ 

 donbtedly the gainer bj^ such suggestive theories." {Observatory.) m 



For further discussion of these interesting questions we must refer ■ 



the reader to the valuable articles of MM. Radau and Wolf in Volumes 

 I and II of the Bulletin Astronomique, and to a paper by Prof. Daniel 

 Kirkwood, read before the American Philosophical Society (November 

 21, 1884) and published in the April number of the tSidereal Messenger. 

 We are glad to learn that M. Wolf intends to elaborate his discussion 

 still further, and that it will be brought out in book form by the pub- 

 lishing house of Gauthier-Villars. 



NEBULA. 



JVeio nebulce. — M. Stephan has published in the Astronomische NacJi- 

 richten, No. 2661, positions and descriptions of 100 nebuloe discovered 

 at Marseilles in the years 1883-85, in addition to the large number pre- 

 viously detected at that observatory. Not the least notable character- 



* In fact, according to M. Faye, the earth is older than the sun. " If it were other- 

 wise, the whole appearance of the sky would be changed; the stars would rise in the 

 west and set in the east; the moon would have a retrograde motion like the satellites 

 of Uranus and Neptune." (Sur VOrigine du Monde, p. 192.) 



