LICK OBSERVATORY, an astronom ical station; on the summit of Mount Hamilton, Santa Clara co., Cal.; erected through the liberality of James Lick, the testator imposing in the trust-deed the obligation of erecting "a powerful tele scope, superior to and more powerful than any telescope yet made." In 1881 the trustees contracted with Alvan Clark & Sons for "an achromatic astronomical object-glass of 36 inches clear aperture" (this being the largest the Clarks would venture to contract for), to be delivered Nov. 1, 1883. The price was $50,000. The flint glass disk was successfully cast by Feil & Sons, Paris, France, early in 1882. Its companion, the crown-glass disk, was cast and ready for shipment at the close of 1882, but the material -was so brittle that it unfortunately cracked in packing. The difficulties attending the casting of the crown disk were ex traordinary, and it was not till 1886 that success crowned the efforts of the Messrs. Feil. This monster object-glass safely reached Mount Hainilton, and was mounted early in 1887. James Lick re served for himself the selection of a suitable site for the observatory destined to bear his name. After considerable deliberation and frequent consultation with good authorities Mr. Lick selected as a site for the observatory, Mount Hamilton. The telescope was put into use early in 1888. The column is of cast iron, 10x17 feet at the base, and 4x8 feet at the top, and weighs 20 tons. On this rectangular column rests the head, weighing four tons, in which is journaled the polar axis. Around this
head is a balcony, on which the assistant astronomer is stationed. By a system of wheels he is able to adjust the instru ment on any star desired, and read its position by microscopes, illuminated by electric light. The polar axis is of steel, 12 inches in diameter, 10 feet long. The declination axis is also of steel, is 10 inches in diameter, 10 feet long. The tube is of steel, 57 feet long. Its diame ter is 4 feet at the center, tapering to ward each end to 38 inches. This is made to follow the star by means of a driving-clock, weighing one ton, con trolled by a double conical pendulum which is placed near the top, and within the column, and is reached by a landing from the spiral staircase. At the side of the great tube three small telescopes of 6-inch, 4-inch, and 3-inch apertures are attached, which serve as finders. The magnifying power ranges from 180 to 3,000 diameters. The object-glass is 36 inches clear aperture, and weighs, with its cell, 532 pounds. By special ac cessories, the telescope is adapted to spectroscopic, photographic, and micro metric work. The center of motion is 37 feet above the base and when the telescope is pointed to the zenith the object-glass is 65 feet above the base of the column. When turning the instru ment in declination the weight that is put in motion is seven tons, and when turning it in right ascension 14 tons is being moved. The total weight of the instrument is 40 tons.