26 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



of the actual existence of the satellite; but whether any tele- 

 scope would ever show it could not be settled except by trial. 

 When, in 1870, Professor ISTewcomb negotiated the contract, 

 for the great Washington telescope with Messrs. Clark, he 

 advised them that their first duty with the new object-glass 

 would be to discover this satellite. But while the object- 

 glass was being finished last summer and autumn, the star 

 was not in a position in which the trial tube could be pointed 

 at it during the night ; and, after its position was improved, 

 the Clarks were too busy in finishing the iron and brass work 

 of the telescope, and too fearful of risking tlic glass by carry- 

 ing it about, to point it at any thing. 



Meanwhile it is likely that Struve had heard of the inten- 

 tion of the Washington astronomer to make the discovery of 

 the satellite in question the first test of the new telescope 

 when it should be mounted, and therefore determined to see 

 if he could not anticipate the discovery with his own smaller 

 glass. On the 29th of March last he w^as successful so far as 

 to find a satellite in the direction of that predicted ; and, we 

 remark, direction alone, and not distance, can be predicted 

 in such a case. It must now be determined whether it is 

 moving around the bright star in the proper way a ques- 

 tion which the Washington telescope, if successfully mounted, 

 will speedily settle. 



THE ERUPTION OF VESUVIUS. 



Palmieri, the famous investigator of the volcanic phenom- 

 ena of Vesuvius, has just written to the Paris Academy of 

 Sciences, through Monsieur St. Claire Deville, that since the 

 publication of the work compiled by him on the phenomena 

 of the recent eruption of Vesuvius, "I have made a great 

 number of spectroscopic researches upon the vapors of the so- 

 called fumaroles, or little vents, and I have found in most of 

 them the presence of thallium; and I have also found in these 

 vajoors other products and substances quite rare at Vesuvius 

 amoncT them boracic acid. Other substances that I have 

 found are mentioned in a printed memoir, where is also 

 given a confirmation of some of your observations, especi- 

 ally on carbonic acid gas. Since the last great eruption of 

 1872, Vesuvius has gradually attained a state of extraor- 

 dinary repose. On the bgrders of the ciater and its interior 



