392 ANNUAL OF SCIENTIFIC DISCOVERT. 



8th magnitude. In Taylor's Madras Catalogue it is marked of the 7th magni- 

 tude. Finally, in Argelander's Uranometria Nova it is called variable. 



Prof. Parson, in a recent communication to the Royal Astronomical So- 

 ciety, describes a star in Libra (Right Ascension, 15h. 45m. and South Decli- 

 nation, 15 49') which suddenly appeared on the 3d of May, 1857, as of the 

 9'5 magnitude, on the 19th of the same month, as of the llth magnitude, 

 and on the 1st of June was no longer discernible. Its whole duration of 

 visibility was therefore only about a month. 



Mr. Baxendal, of England, has also called attention to the variability of the 

 star 30 Herculis. In October and November, 1855, this star was nearly invis- 

 ible to the naked eye, even in the finest night; and the mean of several 

 comparisons with other stars, made at different times, gave its magnitude 5'9. 

 It is now, however, a conspicuous star, and not less than 4'9 magnitude 

 the mean of several nights' estimations since June 18 being 4'85. Professor 

 Argelander rated this star 5'6 magnitude, or less than v. 52 and 42 Herculis; 

 but it is now brighter than any of these stars. On the other hand, it appears 

 from the Radcliffe Observations of 1851 that it was of the 4'8 5'0 magnitude 

 at the end of June and beginning of July of that year. It is very probable, 

 therefore, that its light is subject to periodical changes; but the observations 

 hitherto made are not sufficient to afford even a rough approximation to the 

 length of the period. The red color which is so common amongst the variable 

 stars (especially those of long period) is also very decided in this star. 



OBSERVATIONS ON THE PLANET MARS. 



Prof. Secchi, of Rome, under the date of July 19, forwards to Dr. Peters, 

 of Altona, for publication in the Astronomische Nachrichten, a minute de- 

 scription of the surface of the planet Mars, together with two pictures of the 

 planet taken with an interval of about one-third of a revolution on its axes. 

 The spots seen and drawn by Captain Jacob, at Madras, in 1854, are seen 

 in these representations also, and are therefore to be considered permanent, 

 although there seems to be some confusion among those about the pole. 

 On the other hand, a small round spot, portrayed by Madler in 1830, has cer- 

 tainly disappeared. Any one, however, who will take the trouble to com- 

 pare Secchi's drawings of the curious group of solar spots seen on successive 

 days in March (14, 15 and 16) 1858, with a larger and better drawing of the 

 same group accidentally made on one of the same days, March 15, by Schwabe, 

 and both of them published by Dr. Peters, pages 236 and 342 of the Astrono- 

 mische Nachrichten, will see how much depends on the quality of the tele- 

 scope, the condition of the atmosphere, and the truth of eye and skill of hand 

 of the observer, in determining these delicate tests of cosmical stability or 

 instability in bodies so far beyond our reach. For Secchi's drawings would 

 lead anyone to put unhesitating faith in the popular theory that the spots of 

 the sun are consequences of vortical or whirlwind movements in the equato- 

 rial belts of its atmosphere, so spirally has he drawn them, and so evidently 

 have the little ones on each successive day advanced spirally a certain dis- 

 tance round the larger ones. "Whereas, Schawbe's better drawing shows no 

 such movement whatever, not a trace of it; but, on the contrary, a curiously 

 cracked or shivered condition of each spot in the group, especially the larger 

 ones, through the cracks in the even black surface of which the white light 

 shines with much sharper edges than around the limit of the spot itself; 



