A. MATHEMATICS AND ASTRONOMY. 9 



eral nights, so that the whole observing time of the past year 

 was devoted to this inquiry. In no instance was any change 

 of relative position detected in the positions of the lines of 

 the nebulas and the lead. It follows that none of the nebulae 

 observed show a motion of translation toward or from the 

 earth so great as twenty-five miles per second, including the 

 earth's motion at the time. The observations seem to show 

 that the gaseous nebulae, as a class of bodies, have not " proper 

 motions" so great as many of the bright stars. Since the 

 existence of real nebulae has been established by the use of 

 the spectroscope, Messrs. Abbe, Proctor, and D'Arrest have 

 called attention to the relation of position which the gaseous 

 nebulae hold to the Milky Way and the sidereal system. It 

 was with the hope of adding to our information on this point 

 that these observations of the motions of the nebulae were 

 undertaken. Mr. HusCffins gives the results of observations 

 on seven different nebulae only; and it is to be hoped that, 

 notwithstanding the discouragement which he experiences 

 on account of the unfavorable atmosphere of England, he 

 will continue his researches in this difficult branch of ob- 

 servation. 12 A, 1873, IX., 454. 



THE DOUBLE STAR PROCYON. 



Concerning the minute companion star to Procyon, whose 

 existence has lately been discovered by Otto Struve, the emi- 

 nent Russian astronomer, he states that there can now be 

 no longer any doubt that this companion is, in fact, the per- 

 turbing body which for many years past has been known to 

 be deranging the movements of the brighter star. It is nee- 

 essary to assume, for Procyon, a mass eighty times as great 

 as that of our sun, and for the companion a mass at least five 

 times as great as that of the sun. The observations of the 

 past few months by Otto Struve have shown that the com- 

 panion star is now within a degree of being in the position 

 predicted by Auwers a year ago. 12 A, 1874, X., 37. 



REMARKABLE STELLAR SPECTRUM IX THE MILKY WAY. 



D'Arrest, the director of the observatory at Copenhagen, 

 in some remarks on the nature of the spectra of certain stars 

 and nebulae, calls attention to the spectroscopic revision of 

 the Milky Way, a work with which he has been for some time 



A 2 



