Figure 15. — Grinding lenses in the 

 Alvan Clark & Sons factory. Al- 

 though the tools are rotated by 

 means of steam power, the objec- 

 tive lenses are held and moved by 

 hand. From cover of Scientific 

 American, 24 September 1887. 



Warner & Swasey, has a Clark object glass of 9.53 inches aperture and 

 12 feet focus. 72 



Doane College in Crete, Nebraska, acquired an 8-inch Clark objec- 

 tive, which was equatorially mounted by Professor Godwin Swezey in 

 1884. 73 



There is ample evidence that the Clarks made common as well as major 

 astronomical instruments. M. S. Dowling of Leslie, Michigan, for in- 

 stance, owned a 3-inch Clark refractor, which he advertised to sell in 

 1883. 74 



72 W. V. Brown, "McKim Observatory," Sidereal Messenger, vol. 4 (1885), pp. 



3 5-307- 



73 "Boswell Observatory," Sidereal Messenger, vol. 3 (1884), p. 190. 



74 Advertisement in Sidereal Messenger, vol. 1 (1883), front cover of issue # 9. 



56 



