Trying A Big Telescope

In Cambridge on Snnday evening there was au experimental tp.st of tho great 40 inch telescope nov being ru3de for the University of Chicago by Professor G. E. HaU?, the astronomer, nnder whose dlreetotship the iiew Yerkes observatory of the University of Chicago will euter upon ltscareer; a friend of his, a rising young physicist last coanected with the Massachusetts iu■stituteof tecüaology; Mr. Clark and his assistants. The gn-at lenses, the largest that the world has ever seen, each ot thern eqnal in diameter very nearly to an ordinary buggy wheel, weighing with their mountings more thau 1,200 pounds, were rnaiutained in their position high ín air by a great steel tube, 63 feet in length, and seeming in the dimness of the uight almost interminable. The ponderous tube is poased midway upon a greut shaft, wfaioh permita free motion in every direotion, and this again is perched upon a massive pier of masonry capable of upholding in safety the tons of weight which it is called upon to bear. Monnting the stepladder which served as a teuiporary observing chair, Professor Hale placed his critical eye at the tube, and thon in delibérate succession applied the different tests known to astronomers. To the uneducated eye the glass on this preliminary test was truly at perfeytiun, but the trained eyes of the experts eanght points at times whereby the delioaoy of the instrument ïnight be increaseil Then the phu:et Mars cauie within lange of the iustiument. The first view of this object by P-ofessor Hale brooght forth esclai).of delight, for tiiis telescope by 1!''.t 'rxceeded in light collectiiig abiHt ■ y instrument which lic liarl ■ ■ ' ' turued npou the planer .'. .■■ ' -■! ítself as a great redáis!) '&, ■whose clean cut edges i. . .: ■■■'■■ cellenco of the instrument. IU 1 'itaess with 40 luches ol aperf.irn v. ■ :ilmost sufficient to bliud tho eye, ánd iís great disk was figured with tho datk and ligfat inarkings whicfa define its topograpby. For au houror more the plan - et wae kopt in view, delighting every one of the assembled group with the gplendor of the sight. Then began a search forthesatellites. These ai-e faint stars, visible at their best only with good apertures, and bo close to the planet, as to be hardly beyond the glare of liht which it diffuses. The outer one, Deimos, was easily canght, bnt for some time Phobos, ita companion, could not be discerned. It was at last seen by Mr. Clark almost against the body of its principal, aud for nearly half au hour it was followed by the different meinbors of the company. The lenses, excellent as they have proved to be, will again be placed in the shop, and with the knowledge gained of their minor inaccuracies of figuro they will again uudergo local treatnifiit until they reach that high standard which has placed the Clark glasses ü- ways in the van in point of interesting