388 ANNUAL OF SCIENTIFIC DISCOVERY. 



that did not at all detract from the evidence of their attachment to 

 the sun ; for we never could cut off' completely the highly-illuminated 

 atmosphere through which we look at the sun and all about him. 

 Cut off all we could, there would still be a blaze of light that would 

 extinguish anything even much brighter than these prominences. 



ASTRONOMICAL SUMMARY. 



The Ring of Saturn. Mr. Lassell, the English astronomer, in a 

 recent notice in the (English) Astronomical Society's Journal, states 

 that he has observed that the black shadow of the ring of Saturn, in 

 passing the ball or planet, is evidently knotted or notched, thus con- 

 veying the idea of mountains upon the plane of the ring, intercept- 

 ing portions of the thin line of shadow, and almost breaking it up into 

 a thin line of dots. Capt. TV. S. Jacob, of Hartwell, who observed 

 the same phenomena, May 19th, 1861, is, however, inclined to attrib- 

 ute them to the variation in the shade or tone of the shadow, by 

 which the darker portions appeared to project beyond the rest. 



Movements of Sirius. It has been for a long time known to as- 

 tronomers that there were certain anomalies in the motion of the 

 bright fixed star Sirius, which could not be explained by reference 

 to the aberration or refraction of light, or to imperfections in the instru- 

 ments employed in observation. Mr. T. H. Safford, of the Cam- 

 bridge (Mass.) Observatory, who has recently been engaged in inves- 

 tigating the phenomena in question, considers, as the results of his 

 researches, that the following propositions may be received as 

 certain : 



1st. That the motion of Sirius in declination is not uniform. 



2d. That the deviations from uniformity are readily explained upon 

 Bessel's hypothesis, that Sirius is, as to its visible position, not the 

 centre of gravity of its own system ; in other words, that there is a 

 large invisible mass present in that system. 



The legitimate conclusion from these premises is, that the star 

 Sirius revolves around an invisible companion at a very considerable 

 distance from its optical centre. This period of revolution is be- 

 lieved to be about fifty years. 



Hole in the Moon. Messrs. Bout and Mannheim, who were sent 

 by the French government to Algeria, to observe the great solar 

 eclipse of July, 1860, state, in their official report, that they both saw, 

 one with a telescope, the other with the naked eye, a luminous point 

 on the moon's disc. This phenomenon was perceived by Admiral 

 Ulloa and his companions, in 1778, and by M. Valz, at Marseilles, in 

 1842 ; but it has hitherto been considered an illusion. M. Mannheim 

 states, however, that he saw the brilliant point so unmistakably as to 

 leave no doubt of its being a reality. Its place on the lunar disc has 

 not yet been determined ; but, should it prove to have been always 

 seen at the same place, the only explanation possible would be that 

 the moon is pierced with a hole. 



Recent Researches on Comets. - -During the last eight years twen- 

 ty-two new comets have been added to the list of our'luminous visit- 

 ors, including the most superb one of our age, first seen by Donati 

 on the 2d of June, 1858, and that which flashed with scarcely less 



