ASTRONOMICAL OBSERVATORIES. 



209 



building, consisting of a center with two wings, the whole 

 being 48 feet in length by twenty in breadth. The cen- 

 tral apartment is surmounted by a revolving dome 13 

 feet in diameter, and each wing has an opening through 

 the roof for meridian instruments. Under the dome was 

 placed a Herschelian telescope of 10 feet focus, mounted 

 equatorially. The circle for right ascension was a foot in 

 diameter; the declination semicircle jvas 30 inches in 



WILLIAMS COLLEGE OBSEEVATOBY. 



diameter. Both were made by Mr. Phelps, of Troy, New 

 York, and read to minutes. In the east wing has been 

 placed a transit instrument by Troughton, having a focal 

 length of 50 inches, and an aperture of three and a half 

 inches. In the same room is a compensation clock by 

 Molineux. 



In 1852 an achromatic refracting telescope, having an 

 aperture of seven inches, and a focal length of nine and a 



