JOSEPH WINLOCK. 343 



be completed. In 1867, Mr. Winlock had directed a series of obser- 

 vations with the old meridian circle for the purpose of obtaining an 

 extended list of accurately placed time-stai's. The utility of a larger 

 catalogue of time-stars had been evidenced in the operations for the 

 determination of longitude conducted by the United States Coast Sur- 

 vey, of which Mr. Winlock was consulting astronomer. These obser- 

 vations, which assigned exact places to stars only two minutes apart 

 in right-ascension, but differing widely in declination, were finished in 

 December, 18G8, and have been reduced and printed. In 1871-72, 

 the same stars were reobserved with the new circle, and again for the 

 third and fourth times in 1874 and 1875. An additional set of stars 

 is required for the instrumental constants, expressing errors in azi- 

 muth, collimation, level, &c. For this purpose 5,000 observations 

 were made with the new circle in 1873 and 1874, intended to serve as 

 the basis of an improved catalogue of polar stars, and they are now 

 ready for publication. Therefore, no time has been wasted in reaping 

 the full benefits of the new instrument, although tiie 30,000 observa- 

 tions already made with it are only the first-fruits of the hapjiy de- 

 vices of Mr. Winlock. These materials, to which must be added a 

 catalogue of new double-stars, dissected by the great refractor, and a 

 most laborious and exhaustive work upon stellar photometry, will 

 magnify the forthcoming volume of the Annals of the Observatory, 

 and be a worthy monument to the skill and perseverance of the Direc- 

 tor and his gifted and faithful coadjutors. 



In 1869, Mr. Winlock was instructed by Professor Benjamin Peirce, 

 then Superintendent of the United States Coast Survey, to proceed to 

 Kentucky at the head of a party destined to co-operate with officers of 

 the survey in observing the total eclipse of the sun. on the 7th of 

 August. Mr. Winlock gave his attention, particularly, to the physical 

 aspects of the eclipse, examining the pliotosphere and the chromo- 

 sphere with the spectroscope, and taking eighty photographs of the 

 eclipse, in all its ])hases, seven of them during totality. It was his 

 habit to think out every subject which engaged him for himself; and, 

 when he acted, he seldom followed in the wake of other men. lie 

 found good reasons for rejecting the method of photographing which 

 had been tried in Spain on occasion of the total eclipse of 1860, and 

 which other vVmerican astronomers were preparing to imitate in 1869. 

 As he wished, most of all, to secure a good picture of the corona, he 

 placed the sensitive plates at the focus of the object-glass, thereby 

 economizing the light, and avoiding the distortion by the eye-piece. 

 His success was highly satisfactory. In the best of the pictures, he 



