The mounting of the object-glass is worthy of the occasion. The tube is no less than thirty-seven feet long, and four feet in diameter in the middle part. An iron pier, thirty-eight feet high, beneath which lie the remains of Mr. Lick, supports the equatorial head, and a winding staircase enables the observer to reach the setting circles. Inside the hollow pier is the powerful driving-clock which turns the telescope to follow the heavenly bodies in their apparent movements. Finders of six, four, and three inches diameter, rods for the manipulation of the instrument, and all necessary accessories, complete what must long remain one of the most perfect instruments at the service of astronomical science. The $200,000 expended upon it have already been amply justified by the work accomplished, while Mr. Lick’s dream of immortality has become a reality. The following list indicates some of the large refractors now doing active service: Aperture Observatory 36 inch [Lick] California. 30 ” Pulkowa, Russia. 30 ” [Bischoffeim] Nice. 28 ” Greenwich. 27 ” Vienna. 26 ” Washington. 25 ” [Newall] Cambridge. 24 ” [Lowell] Mexico. 23 ” Princeton, New Jersey. It is right to add, however, that opinion is still greatly divided as to whether these telescopes of large aperture really repay the expense and labor involved in their erection and use. On the very rare occasion when the “seeing” is practically perfect—which occurs perhaps only a few hours in a year—it is probable that the superiority of a large telescope is very marked, but under average conditions there seems to be little advantage over instruments of moderate size for many classes of observations. Certain it is that a great deal of valuable work is done with comparatively small telescopes, ranging from six to fifteen inches aperture, and this in all departments of astronomical research. Hence, some of the most active observatories do not figure in the above list; among them may be mentioned the observatories of Harvard College, Potsdam, Paris, Heidelberg, Cape of Good Hope, Edinburgh, South Kensington, Stonyhurst College, and the observatory of Dr. Isaac Roberts at Crowborough, England.