Alvan Graham made similar observations. His most noted find, a 

 classic case of serendipity, was the small companion of Sirius. The ex- 

 istence and position of this star had been predicted from the proper 

 motion of Sirius, and the star had been frequently sought by others. Alvan 

 Graham, however, was probably unaware of these previous researches. 94 

 On the evening of 31 January 1862 the Clarks — Alvan watching the 

 time, and Alvan Graham at the ocular of the 18/2 -inch telescope — were 

 trying to ascertain how long the light of Sirius was perceptible before the 

 star itself was in view. 95 While Sirius was still behind the corner of a 

 building Alvan Graham noticed the Pup, before it had been in the field 

 for three seconds. 96 For this discovery he was awarded the 1 862 Lalande 

 Prize of the French Academie des Sciences. It is curious to note that al- 

 though the Clarks designed and built micrometers, they seem not to have 

 measured the star systems they discovered. As Dawes had done for Alvan, 

 senior, S. W. Burnham, in 1879, published measurements of fourteen 

 binaries discovered by Alvan Clark, junior. 97 



Extensive preparations were made to observe each solar eclipse which 

 occurred during the second half of the 19th century. Besides making 

 many of the instruments used to study the sun, the Clarks participated in 

 several of these expeditions. George and Alvan Graham observed the 

 total eclipse of 7 August 1 869 at Shelbyville, Kentucky, as members of the 

 United States Coast Survey party organized by Joseph Winlock of Har- 

 vard. Using the 5*/ 2 -inch equatorial refractor the Clarks had recently 

 made for the Harvard Observatory, George Clark and John A. Whipple, 

 a Boston photographer, obtained eighty good pictures of the eclipse, 

 three of which were taken during totality. 98 A chronograph, electrically 

 connected with the shutter, recorded the time of each exposure. Alvan 

 Graham's observations with a small refractor were undistinguished ex- 

 cept for his confirmation of a flock of dark objects — presumably 

 meteors — passing in front of the moon. 99 



94 Simon Newcomb, "New Refracting Telescope of the National Observatory, 

 Washington, D.C.," op. cit., p. 327. 



95 John Fulton, Memoirs of Frederick A. P. Barnard (New York, 1896), pp. 245-246. 



96 "Remarks by Alvan Clark on Receipt of Rumford Medal," op. cit.. p. 248. 



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

 Journal of Science, vol. 17 (1879), pp. 283-289. 



98 U.S. Coast Survey Report, i86g, p. 138. 



99 Ibid., pp. 136, 139. 



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