8 ANNUAL BECORD OF SCIENCE AND INDUSTRY. 



upon the movements of the asteroid Themis. The result is 

 singularly in accordance Avith those that have been hitherto 

 accepted, and is based on all the observations made during 

 the seventeen years 1853-1870, and gives the mass of Jupiter 

 ^^ 1047.538 0.192 - '^^^^ rcsult rcccutly obtained by Muller from 

 liis study of the movements of Faye's comet was 1047.788=1= 

 0.186. The most generally used by astronomers was long 

 since determined by Bessel from observations of Jupiter's 

 satellites, and is 1047.879d=0.159. 1 B, March 2, 1873. 



CHANGES ox JUPITEr's SUEFACE. 



Tacchini reports that, during January, 1873, he has ob- 

 served quite remarkable changes in the appearance of the 

 belts of Jupiter. The belts were no longer parallel to his 

 equator as usual ; but from the equator southward were seen 

 numerous brilliant white spots, and also many black spots 

 surrounded by white. These, and other appearances, are 

 evidently due to some peculiar alterations in the planet, and 

 Tacchini calls upon all having good telescopes to give special 

 attention to this planet. 



MOONS OF URANUS. 



Observations of the planet Uranus, at the Bothkamp Ob- 

 servatory, in the spring of 1871, revealed occasionally, under 

 favorable conditions, small stars near it, two of which certain- 

 ly, and two others probably, were satellites. Their periods 

 of revolution were fixed, by calculations of Vogel, at 13.462, 

 8.705, 4,15, and 2.54 days respectively. 19 f, November 23, 

 1872,383. 



WHITE APPEARANCES IN THE MOON. 



A writer in Nature suggests that the white telescopic ap- 

 pearance in many parts of the moon's surface, resembling 

 snow, may be really a coating of salt on extinct volcanoes 

 of that satellite. The dazzling, snow-white efl?ect of the 

 mountains is commented upon ; and it is thought that a clew 

 to the phenomenon is furnished by the late eruptions of Mount 

 Vesuvius. In this instance a crust of crystals of salt was 

 formed over the entire surface of the lava on cooling. 12 A^ 

 Ja7U(ari/ 16,1816,221. 



