The LIBRARY BUILDING contains temporarily the offices of the Superintendent, Adjutant, Quartermaster, and Treasurer. On the second floor, which is not usually open to visitors, is situated the Lecture-room and apparatus of the department of Philosophy and Astronomy. The dome contains an equatorial telescope, and the flank towers a transit instrument and mural circle. The Library occupies the east end of the building. It contains about 20,000 volumes, chiefly on professional and scientific subjects, and several fine portraits of former Superintendents and Chiefs of the Engineer Department. The capacious RIDING HALL stands on the bank of the river, a little below the Library; and from the interesting exercises therein, it is deservedly regarded as one of the most attractive points at the Military Academy. The hours for riding are from 11 A.M. to 1 P.M., except during the period of the Cadets' encampment, with occasional interruptions, when the evolutions of a squadron are practised on the Plain. The course of instruction embodies running at the heads, running at the ring with poised sabre, exercises with pistols, leaping bars and hurdles, and many other feats which afford little room for monotony or wearisome interest, even among those accustomed to witnessing equestrian displays. Northward from the Library a path leads down the bank to KOSCIUSZKO'S GARDEN--a shelving terrace overhung with shrubbery, and rendered inviting by a cool spring of water, and a tradition that the patriot Pole, whose name the spot bears, here sought retirement and seclusion. The Monument to "Dade and his Command" tells its own story, and American history has yet to furnish an example of devotion to duty similar to that exhibited by those whose names are here inscribed. A little beyond is seen Battery Knox, whose armament proclaims the tidings on all occasions of national joy or sadness. From this point, the lower pathway, called the "Chain Battery Walk," conducts the visitor through a delightful ramble to Gee's Point and the North Wharf, or by a branch, to the Hotel above. The upper path returns to the road along the crest of the bank, and a few steps brings the tourist to FORT CLINTON.