In 1873 the Clarks sold a 12-inch achromatic objective to the Austrian 

 government for the Imperial Observatory at Vienna. As the lens was not 

 delivered until the new observatory was built, Alvan Graham had the 

 use of it for several years. During this time he discovered at least five pairs 

 of double stars, including the companion of y Lyrae. 244 



In 1 87 1, while arrangements for the 26-inch equatorial of the U.S. 

 Naval Observatory (q.v.) were being made, Leander McCormick 

 ordered a similar refracting telescope for his native state of Virginia. The 

 Clarks would have completed this instrument within a few years, but 

 held off for a while because of McCormick's financial difficulties. This 

 delay gave them a chance to learn from some of the mistakes of the 

 Washington instrument. The inner surfaces of the Virginia 26-inch ob- 

 jective, for instance, were given slightly different radii, so as to avoid the 

 annoying "object-glass ghost." The driving clock was connected with a 

 Seth Thomas clock located in the computing room of the observatory. 

 The filar micrometer, like that at the University of Wisconsin (q.v. ) , was 

 provided with Burnham's illumination. The telescope was finally erected 

 at the Leander McCormick Observatory at the University of Virginia in 

 1884. 245 This observatory also boasts a 6-inch Clark equatorial refractor 

 of i892. 246 



Between 1882 and 1893 the Warner Observatory in Rochester, 

 New York, housed the 16-inch Clark equatorial refracting telescope be- 

 longing to Lewis Swift (q.v. ) . 



Many of the telescopes originally made in the 1850's by Henry Fitz 

 were later extensively remodeled. One such instrument is the 6 J/2 -inch 

 refractor at Washington University in St. Louis, Missouri. In 1882- 

 83 the Clarks reground the objective and Warner & Swasey made a 

 new mount. 247 



The physics department of Washington and Jefferson College, at 

 Washington, Pennsylvania, now has possession of the 7 1 / 2 -inch objective 



244 S. W. Burnham, "Double Stars Discovered by Alvan G. Clark," American 

 Journal of Science, vol. 17 (1879), p. 285. 



245 "Leander McCormick Observatory," Scientific American, vol. 60 (1889), p. 55. 



246 P. Stroobant, Les observatoires astronomiques et les astronomes (Tournai/Paris, 

 J93 1 ), P- 5°- 



247 From private correspondence with Richard H. Lytle, University Archivist, 

 Washington University. 



106 



