Lenox conveyed to the trustees three hundred thousand dollars in stocks of the county of New York and bonds and mortgage securities, and also the ten lots of land fronting on Fifth Avenue on which the library-building now stands. One hundred thousand dollars were set apart for the formation of a permanent fund, and two hundred thousand dollars for a building-fund. Contracts for a library-building were made early In 1872, and work on it was begun in May of the same year,--the structure being finished in 1875. It has a frontage of one hundred and ninety-two feet on Fifth Avenue, overlooking the Park, and a depth of one hundred and fourteen feet on both Seventieth and Seventy-first Streets. The general plan is that of a central structure connecting two turreted wings which enclose a spacious entrance-court. From the court the visitor enters a grand hall or vestibule, from which every part of the building is reached. At either end is a spacious library-room. Stone stairways lead from each end of the vestibule to the mezzanine, or half-story, and the second-story landings. From the latter one enters the principal gallery, ninety-six by twenty-four, devoted to sculpture, and opening on the east into the picture-gallery. At either end of the hall of sculpture are library- and reading-rooms similar to those on the first floor. The stairway on the north continues the ascent to an attic or third-floor gallery. The building throughout is fitted up in a style befitting a shrine of the arts. The first-floor library-rooms are one hundred and eight feet long by thirty feet wide and twenty-four feet high, with level ceilings, beautifully panelled and corniced. The sides of the hall of sculpture are divided by five arcades, resting on piers decorated with niches, pilasters, and other architectural ornaments; the ceiling has deep panels resting on and supported by the pilasters; the walls are wainscoted in oak to the height of the niches. The picture-gallery is forty by fifty-six, well lighted from above by three large skylights. Iron book-cases, with a capacity for eighty thousand volumes, are arranged in two tiers on the sides of the galleries. The whole structure is as nearly fire-proof as it could possibly be made, and its massive walls and stone towers make it one of the prominent architectural features of the avenue. While the building was in progress, several benefactions of interest had accrued to the library. Mr. Lenox had given an additional one hundred thousand dollars, and in 1872 one hundred thousand dollars more, and Mr. Felix Astoin had promised to bestow his fine collection of some five thousand rare French works. On the 15th of January, 1877, the first exhibition of paintings and sculptures was opened to the public, and continued on two days of the week to the end of the year, and on the 1st of the following December an apartment for the exhibition of rare works and manuscripts was also opened to the public.