THE REiORl),
THE OBSERVATORY,
Las'!1 NovenibPT1 I he asl r< building" way so far com pi et pel (hat ihe setting up and adjusting of the instruments cunld be begun. The aeoompanying; cut gives a fair view of the observa tory. Itci owns the hill which is about 200yd s.easi of the University and just south of ihe road leading to Collegeville. The top of the revolVing' dome is ;\'2 Ft. above the ground. Tlnj entrance faces the south and leads to what is designed to be the computation-room; itsdimeiisions are 1 0x1314 ft. Adjoining if is the transit-instrument and the chronograph; this part is 93
move from east to west, which is really due to tie earth's mot ton in opposite direction, so that an object once brought into the field of the telescope^ will remain visible as long as the ol iserver pleases to keep it pointed at the object. This, I think, is a satisfactory answer to t he quest ion what that merry-go-round (meaning the governors of the driving-clock) is for, which nearly ^vwy youngster on seeing is sure to ask. Declination and right ascension, or hour circles make it easy to direct the instrument to faint celestial bodies, and also to determine their position if not yet known, as that of a new comet. The focal-length of its four-inch achromatic object-glass which was ground by J. A. Brashear of world-renown, is GO inch. To the tube of the telescope a small telescope called ¦'the finder'3 is fastened, which comprises a much larger part of the heavens than the large one so that, a star, for instance, is only then visible in the telescope proper, when it has tii'st been brought into the finder's field usually indicated by four wires forming a little square. By means of slow-motion screws. the image of any object" viewed can be placed centrally in the field. A number of eye-pieces of different magnifying power can be employed with the equatorial (another name for a telescope mounted like ours) to suit the nature of the object and the taste of the observer. Another of our instruments, and
