JOSEPH WINLOCK. 343 



bo oompli'ted. Tii lsi')7, Mv. AViiilock li;iil diroctt'il n series of ol)ser- 

 vatioiis witli tlir old iiu'ridiiin circle for tlic jtiirpose of ohtaiiiiii^r an 

 exte'iidt'd list of uccuratidy phu-ed time-stars. Tiie utility of a lar>^er 

 catalogue of time-stars had beeu evidenci'd in the operations for the 

 dt'termiiiation of longitude conducted by the Uiiiied States Coast Sur- 

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

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

 in right-ascension, but differing widely in declination, wen; finished in 

 December, 18 G8, 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 187o. 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 the 30,000 observa- 

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

 vices of Mr. Winlock. These materials, to which must be aiUIetl 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 moniunent 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 photosphere and the chromo- 

 sjihere with the spectroscope, and taking eighty photographs of the 

 eclipse, in all its phases, 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 tlie method of photographing which 

 had been tried in Spain on occasion of the total eclipse of 18(50, and 

 which other American astronomers were preparing to imitate in 18G9. 

 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 



