440 SCIENTIFIC EECOED FOE 1885. 



- - - "The volume closes with a count of the Durchmusterung 

 stars between — 2° and -f 13°, a determination of the constants of some 

 of the other instruments, meteorological observations for 1884, a sum- 

 mary of the same as taken at Madioon continuously from 1853 to 1884, 

 and is throughout a highly creditable publication." - - - {Science, 

 November 20, 1885.) 



Willets Point Observatory. — The astronomical observations made dur- 

 ing 1885 were of the same nature as those described at some length for 

 the preceding year in the "Account of the Progress in Astronomy in 

 1884." The observatory is established for training engineer of&cers in 

 the applications of practical astronomy to geodesy. The course of in- 

 struction, jis well as the arrangement of the observatory building and 

 its equipment (described and illustrated with a plan of the observatory 

 in General order No. 3, series of 1881, and Printed order No. 3, series of 

 1882), may well be taken as a model in this branch of astronomy. A 

 large number of latitude observations made by different observers from 

 1880 to 1884, and apparently showing a steady decrease in the latitude 

 of the post, has been submitted to a critical discussion by Miss Alice 

 Lamb, of the Washburn Observatory. By selecting the best determined 

 stars, and by rejecting the observations with one of the instruments, 

 and the Avork of some observers, whose probable errors are about twice 

 as large as the probable errors of those whose work is retained, she 

 concludes that there is strong reason to attribute the systematic change 

 to errors of observation rather than to a real diminution of the latitude. 



Yale College Observatory. — The following is a brief statement of the 

 work accomplished or in progress under the direction of Dr. W. L. 

 Elkins, who has charge of the heliometer, the only instrument of that 

 class, we believe, in operation in this country. 



The principal object of research has been the triangulation of the 

 Pleiades, to which work the instrument was devoted from September, 

 1884, to March, 1885. It was originally intended to confine the investi- 

 gation to the stars measured at Konigsberg; the scheme has been ex- 

 tended, however, to include all the stars in the Bonn Durchmusterung, 

 within certain limits, down to the magnitude 9-2, making sixty-nine stars 

 in all. The reductions are in a forward state. 



Other observations are reported : 



Measures of the Moon from neighboring stars, diameters of the Moon, 

 diameters of Venus, and the outer ring of Saturn, and a series of ob- 

 servations of Titan referred to its primary, which is being continued by 

 Mr. A. Hall, jr. 



There have been various additions made to the working appliances 

 of the instrument. The oil-lamps illuminating the scales and circles 

 have been replaced by half-candle incandescent lamps. The most im- 

 portant addition is, however, the registering micrometer, which Messrs. 

 Kepsold have made for reading the scales. The principle consists in 



