as well as the various other biographies from Wendell's pen, shows a 

 sympathetic awareness of the optician's personality. 252 



In 1868 Wesleyan University, at Middletown, Connecticut, built 

 a second astronomical observatory and equipped it with Clark apparatus. 

 Except for small pieces, Clark instruments were usually made to order. 

 The surviving correspondence between the Clarks and Prof. John M. 

 Van Vleck of Wesleyan shows that, in this case, the Clarks not only 

 designed the instruments but gave advice on the construction of pier and 

 dome as well. 



The new dome enclosed a 12 -inch refractor of about 15 feet focus; 

 this was equatorially mounted and provided with finder, circles, driving 

 clock, and micrometer. The cost, including delivery to the observatory, 

 was $6,000 in gold. 253 After fifty years service this telescope was trans- 

 ferred to Miami University (q.v.). It has recently been given to Leslie 

 Peltier (q.v.). 



During the solar eclipse of 7 August 1869, Van Vleck used, for the first 

 time, a Clark spectroscope attached to a 3/2 -inch portable Clark equa- 

 torial. 254 The spectroscope was designed for use either with the large equa- 

 torial or in the laboratory. It employed a single glass prism and a scale of 

 equal parts for locating spectral lines. The Clarks apparently did not real- 

 ize the importance of precise spectroscopic determinations. They made 

 this instrument to answer all purposes except exact measures because, "the 

 observations for locating the lines are excessively tedious and but few 

 persons have the patience or time to do much with them." 255 



Van Vleck apparently intended to order a chronograph from the 

 Clarks. In a letter of 1868 the Clarks replied that they had never made 

 chronographs, that Wm.. Bond & Son was the chief concern in that busi- 



252 Oliver C. Wendell, "A Tribute From Mr. Clark's Personal Friend," The 

 Cambridge Chronicle, 26 June 1897. See also Oliver C. Wendell, "Alvan Graham 

 Clark," Proc, American Academy of Arts and Sciences, vol. 33 (1897-1898), pp. 520-524; 

 and Oliver C. Wendell, "Alvan Graham Clark," Astrophysical Journal, vol. 6 (1897), 

 pp. 136-137. 



253 Alvan Clark & Sons to Prof. J. M. Van Vleck, 10 April 1868 (letter in Wesleyan 

 University Archives). 



254 U.S. Nautical Almanac Reports of Observations of the Total Eclipse of the Sun, August 

 7, 1869, pp.81, 87. 



255 Alvan Clark & Sons to Prof. J. M. Van Vleck, 18 November [1868?] (letter in 

 Wesleyan University Archives). 



108 



