8 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tion of this is that the star maybe surrounded by a rotating 

 nebulous ring of different thickness at various parts, so that 

 variations of both color and intensity are the results of ab- 

 sorption. 



DOUBLK, BINARY, AM) MULTIPLE STARS. 



Mr. Burnham, of Chicago, has published his ninth catalogue 

 of new double stars discovered with the G-inch refractor. It 

 comprises the discoveries of 1S76 and the first part of 1877. 

 It contains Nos. 453-482, i. e. thirty stars ; of these, eighteen 

 are closer than 2.11". 



No. 4 of the publications of the Cincinnati Observatory 

 for 1877 has been received. It gives the measures of 517 

 double stars. The introduction contains an account of the 

 methods of observing. Positions are measured by placing 

 the objects between parallel wires, and with both forward 

 and backward motions of the tangent screw and distances, so 

 as to eliminate the zero and to make the bisections symmet- 

 rical. The three observers were found to have a personal 

 equation in position-angle, which Professor Stone refers pri- 

 marily to the position of the observer's head. The observa- 

 tions are compared with older series, and the probable errors 

 determined. The colors are noted on a new plan, by using 

 numbers, which allow them to be expressed briefly. 



This publication of the detailed observations is followed 

 by a volume of il/ecm Results, which is a summary of the pre- 

 ceding work. It is in octavo form, sixty stars on a page, and 

 contains observations on 517 such pairs of stars. On the 

 average, about two observations have been made on each 

 pair, both in position and distance. The various columns 

 have for caption, "Number," "Name," "Epoch," "Position- 

 Angle," "Distance," and " No. of Obs." Many close pairs 

 have been measured, and also many neglected stars are to 

 be found in the list. 



The Rt ndiconti of the (Italian) Royal Academy of Sciences 

 for May, 1*77, contains a memoir by Signor A. Nobile on 

 the trapezium of Orion (^ 748). The instrument employed 

 was a refractor of 0.14" 1 (5.51 inches) aperture. The method 

 of observation employed was that invented by Nobile, and 

 previously described by him. We possess previous determi- 

 nations of tin- relative positions of these stars by W. Struve 



