ON THE PROGRESS OF SCIENCE. XXIII 



tauri exceeds nine tenths of a second, or that its distance from the sun is 

 about twenty billions of miles. So far as we have the means of judging, 

 this star is our -nearest neighbor in the sidereal spaces. The attention of 

 foreign astronomers is still directed to the irregularities in the proper 

 motions of stars, and the opinion seems to be gaining ground that many 

 of them are accompanied by non-luminous companions. The most remark- 

 able astronomical discoveries of the past year have, undoubtedly, been 

 those of the American astronomers, relative to the nature and constitution 

 of Saturn's rings ; two new ultra-zodiacal planets, Irene and Eunomia, have 

 also been added to the solar system, by Messrs. Hind and Gaspasis. An 

 invention of great value has been made by Prof. Mitchel, of Cincinnati, 

 for the observing and recording right ascension and N. P. distance ; a new 

 lunar formula has also been constructed by Mr. Longstreth, of Philadel- 

 phia, by which an error, hitherto disregarded, is eliminated, and perfect 

 coincidence with observation is obtained. The valuable astronomical jour- 

 nal, JJstronomisches Nachrichten, the existence of which was endangered 

 by the recent death of its editor, Prof. Schumacher, has been continued by 

 Prof. Hansen and Dr. Petersen. 



The valuable mathematical and astronomical library of the late Prof. 

 Jacobi has been purchased during the last year, at Berlin, for Harvard 

 University. It consists of about nine hundred volumes, many of them of 

 great value, and was considered one of the most complete libraries of the 

 kind in Europe. 



The British Surveyors in the North American Provinces have adopted 

 the longitude of the Observatory in Cambridge as the zero for constructing 

 their maps and charts, being satisfied that the longitude of that point is 

 better known than any other on this continent. To facilitate an important 

 object, mutually advantageous to the United States and Great Britain, in 

 determining the longitude of various places on the coast, a telegraphic 

 communication has been established between the Observatory at Cambridge 

 and Halifax. This communication is now complete, and is effected by a 

 single battery, through a space of seven hundred and seventy miles, by 

 the course of the wires, and the transit of a star at either of those places 

 is distinctly recorded at the other. These operations are in connection 

 with the U. S. Coast Survey, and they promise valuable results, in afford- 

 ing a greater security to navigators, on a long line of coast much fre- 

 quented by American vessels. 



Among the other topics of interest, related to astronomy, which have 

 occurred during the past year, Foucault's experiment, on the rotation of 

 the plane of simple pendulum's vibration, has excited universal attention. 

 In regard to this experiment, Prof. Airy, in his address before the British 

 Association, says, "It is certain that M. Foucault's theory is correct; 

 but it is also certain that careful adjustments, or measures of defect of 



