OF ARTS AND SCIENCES. 



19 



4. Solar Eclipse of May, 1845. 



Micrometric Measurements during the Solar Eclipse of May 5l.li, 

 1845. Corrected for Refraction. 



Cambridge Observatory, Lat. 42*^ 22' 49", Long. 4^- 44!"- 32': 



" Note. The sky was clear, but the sun's limb was very tremulous. 

 The refraction corrections are somewhat uncertain, the sun being but 

 one degree above the horizon at the commencement of the series. 

 The observations were made by William C. Bond with the 46-inch 

 equatorial telescope (aperture 2f inches), and Troughton's spider- 

 line position micrometer. 



" The time of ending of the eclipse, expressed in mean solar time 

 for the meridian of this Observatory, as observed by Hon. William 

 Mitchell, with an achromatic telescope, by Tully, of 3j^-inch aper- 

 ture and 45 inches focus, was 5"- IT- 18™- 02.2'-. 



" As observed by W. C. Bond, with a refractor by Troughton 

 and Simms, of 2f-inch aperture and 46 inches focus, it was b"^' 17''- 

 IB-" 04.3". 



" As observed by George P. Bond, with a refractor by Lerebours, 

 having a rock-crystal object-glass of 3 inches aperture and 4 feet 

 focus, it was 5"- IT- 18'"- 04.2'-. 



