40 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



is thus suggested of the existence of a system of bodies, such 

 as the planets revolving around the sun, in which the masses 

 of the different bodies are so adjusted to their mean distances 

 as to insure to the system a greater degree of stability than 

 would be possible by any other distribution of masses. The 

 mathematical consideration of the criterion for such a dis- 

 tribution of the masses has not yet been fully developed, and 

 the problem is here introduced for the purpose of calling the 

 attention of mathematicians and astronomers to it. Smith- 

 soiiiaii Report J 1871, 272. 



THE SPECTEUM OF THE SOLAK ATMOSPHERE. 



Rayet has communicated some novel observations made 

 by him on the spectrum of the solar atmosphere. He on the 

 16th of August made the remarkable and entirely unexpect- 

 ed discovery of the reversion of one only of the two lines 

 that constitute the sodium line D in the solar spectrum. At 

 a proper altitude, one only of these two lines, namely, the 

 less refrangible, seemed bright, and at a proper distance from 

 the solar limb both the lines were reversed the less refrangi- 

 ble w^as always far brighter than the other. As yet these 

 two lines of the spectrum have always appeared identical in 

 the laboratory experiments; but it is notable that they are 

 not precisely equal, and that upon the sun the most refrangi- 

 ble is slightly brighter. In considering his observations 

 upon other substances, Rayet considers it probable that there 

 may be a general law applied in a great number of neigh- 

 borinsc lines belono-ingj to the same substance. The less re- 

 frangible will be those that are most easily reversed. 6 J^, 

 1873,530. 



sporee's obseevations upon the sun. 



Sporer has quite recently communicated to the Academy 

 of Sciences in Berlin the result of his recent observations upon 

 the solar spots and protuberances. In the case of many of 

 the protuberances, known as the red flames, it seems to him 

 that they owe their origin to the presence of solar cyclones. 

 "Sporer accounts for the presence of protuberances on several 

 successive days in very nearly the same spot by the suppo- 

 sition that volcanic eruptions take place. He divides the 

 protuberances into two classes, those that are of the nature 



