Democratic Sentinel, Volume 19, Number 31, Rensselaer, Jasper County, 9 August 1895 — THE LARGEST LENS. [ARTICLE+ILLUSTRATION]

THE LARGEST LENS.

Work On It Has Been Finished at Cam* bridge, Mass. After a year’s work the 40-inch lens of the Yerkes telescope has been finished at Cambridge, Mass., and will be shipped soon to its destination. This lens is four inches larger than that of the Lick telescope. With this monster telescope great things aW predicted in the field of astronomy, and it is expected to reveal some interesting facts of Mars and its canals. The lens of the Yerkes telescope, when the glass came from Paris in the rough, and before a stroke of work had been done upon it to fashion it into its present delicate and beautiful shape, cost $40,000. Probably the grinding and polishing of the lens, which have been going on for two years, cost as much again, while several hundred thousand dollars were required to furnish the grounds and buildings for the new observatory, with its numerous instruments and the elaborate and enormous brass tube for the great telescope, besides the endowment requir-

ed to supply a permanent fund for the maintenance of the institution. The great crown glass UQw-at Cambridge is about three inches thick in the middle and one and a quarter inches at the outer edge. The two pieces that make up the lens weigh together 1,200 pounds. Being fragile, in spite of their great size, they must be handled with the utmost care. The

lens will soon be shipped from Cambridge to the shores of Lake Geneva, in Wisconsin, where the observatory is to be situated.

THE YERKES TELESCOPE LENS.