A. MATHEMATICS AND ASTRONOMY. 47 



power of the reading microscopes to several hundred times; 

 smallness of dimensions, and consequent cheaj^ness; and avoid- 

 ance of almost all the questions of flexure and local efiects of 

 temperature." 



CINCINNATI CATALOGUE OF NEW DOUBLE STARS. 



The Cincinnati Observatory has just published in a neat 

 octavo form a catalogue of fifty new double stars, discovered 

 with the 11-inch refractor, by H. A. Howe, with the places of 

 the stars for 1880.0. The pages are well arranged, every 

 thing relating to the positio7i of the star being on the left- 

 hand page, and the position-angle^ distance, and magnitudes 

 of the doubles, with the date of discovery and remarks, being 

 opposite, on the right-hand page. 



The stars are mostly small, and all are below the sixth 

 magnitude; but, on the other hand, the pairs are close, no 

 less than twenty-one out of the fifty pairs being two seconds 

 of arc or less in distance, and none greater than eight seconds. 

 Most of them are also very far south, in a field comparatively 

 un worked before. 



LIST OF LATITUDE STARS EMPLOYED IN THE COAST SURVEY. 



It has heretofore been the custom in the Coast Survey to 

 determine the latitudes of the various astronomical stations 

 by means of pairs of stars selected from the catalogue of the 

 British Association, for observation by Talcott's method. 

 These pairs were observed in the field, and the note-books 

 sent to Washington, where the final reductions were made. 

 The declinations for the observed stars were obtained from a 

 comparison of good modern authorities, such as the publica- 

 tions of the observatories of Greenwich, Washington, Rad- 

 clifFe, and Armagh. In many cases the observatories of 

 Washington and of Cambridge, Mass., have determined the 

 declinations specially. The Coast Survey has selected from 

 the "Durchmusterung" all stars between the declinations of 

 4-88 40' and 1 48', and above the 5.9 magnitude, 2164 in 

 all, and has published in its report for 1873 a list of these, 

 with the approximate places for 1880.0. 



It is further intended to publish shortly accurate places of 

 all these stars, so that a complete working catalogue of nearly 

 all the naked-eye stars of the northern hemisphere will be 



