=The Façades.=--The exterior walls of the Library are constructed wholly of granite, quarried in Concord, New Hampshire. The stone is a close-grained variety, so even and light in tone that when the sun is shining upon it the effect is almost as brilliant as if a white marble had been used. The massive buttresses which support the Octagon at each of its eight corners, and so much of the Octagon wall as is visible from the outside, are also granite, but of a different quality, slightly darker in hue, and coming from quarries in Maryland. [Illustration: NYMPH AND SEA-HORSE, FROM THE FOUNTAIN.] The Library is in three stories: the basement story of fourteen feet; the first story, or main library floor, of twenty-one feet; and the second story of twenty-nine feet-making a height of sixty-four feet for the three stories at the lowest point. Adding to this the base at ground level, and the simply designed balustrade which surmounts the whole, the total height is seventy-two feet above the ground. Beneath the entire structure is a cellar, below the level of the ground outside, but within opening upon the interior courts. The granite of which the walls are constructed is rough, or “rock-faced,” in the basement story; much more finely dressed in the story above; and in the second story brought down to a perfectly smooth surface. The windows in the basement are square-headed, as also on the library floor, except along the west front, where they are arched, with ornamental keystones. Throughout the second story they are again square-headed, but with casings in relief, surmounted by pediments alternately rounded and triangular, and, along the west front, railed in at the bottom by false balustrades. To prevent the monotony incident to a long, unrelieved facade, the walls are projected at each of the four corners and in the centre of the east and west sides, into pavilions, which, in addition to being slightly higher than the rest of the rectangle--thus allowing space for a low attic-story--are treated with greater richness and elaboration of ornamental detail. The corners are set with vermiculated granite blocks--blocks whose surface is worked into “vermiculations” or “wormings.” The keystones of the window-arches in the first story are sculptured with a series of heads illustrating the chief ethnological types of mankind. Along the second-story front runs a portico supported upon a row of twin columns, each a single piece of granite, with finely carved Corinthian capitals. The pedestals which support the columns are connected by granite balustrades, so that the portico forms a single long balcony, with an entrance through the windows which look out upon it. THE ENTRANCE PAVILION. [Illustration: NEPTUNE, FROM THE FOUNTAIN.]