1887.] NEW YORK ACADEMY OF SCIENCES. 107 



Reflectors. 



Owner and Location. Constructed by. Aperture. Remarks. 



Lord Rosse, Birr Castle, Rosse, 6 feet. 



William Herschel, Slough, W, Herschel, 4 '* Out of use. 



^ S i n c e d e - 



Lassell, Liverpool, etc., Lassell, 4 " | stroyed. 

 EUery, Melbourne, Grubb, 4 " 



Paris, Martin, Eichens. 4 " Silvered glass. 



Lord Rosse, Birr Castle, Rosse, 36 in. Silvered glass. 



Common, England. 36 " 



Tissex-and, Toulouse, . Foucault, 33.4 " 



Stephan, Marseilles. Foucault, Eichens, 31.5 " 



H. Draper, nr. N. Y. H. Draper, 28 " Silvered glass. 



Lassell, Maidenhead, Lassell, 24 " Metal. 



W.&H. Herschel, Slough, Several mir- 



andC.G. H., W. & J. Herschel, 18 " rors. 



H. Draper, nr. N. Y, H. Draper, 15 



M'Lean, Tunbridge AVelIs,With & Browning, 15 



Pritchard, Oxford, De La Rue, 13 



Worthington & Baxendell, 



Manchester, With & Browning, (?)13 " 



And many others. 



Note. — The object-glass of the Lick equatorial is to cost, $52,000 00 



Photographic lens of crown glass 13,000 00 



Mounting of telescope 42,000 00 



Dome and machinery 56,800 00 



Total 1163,800 00 



Mr. A. Swazey, of Cleveland, furnishes the following data in 

 regard to the great Lick telescope : 



Focal length 56 feet. 



Length of polar axis 12 feet. 



Diameter of polar axis 12 inches, with a cylindrical hole 

 5 inches in diameter. 



Declination axis : length, 12 feet ; diameter, 10 inches, with 

 5-inch hole. 



Largest circles 3 feet in diameter. 



The tube of steel will weigh about 3 tons. The tube and all 

 the movable parts (polar axis, etc.) will weigh 12 tons. The 

 ^Miead'^ will weigh 3 tons, and the pier 10 tons, making a total 

 •of 25 tons. 



The lenses with their cell weigh about 700 pounds. 



