Entering by either of these three bronze doors, one passes immediately through a deep arch into the Main Entrance Hall. It is constructed of gleaming white Italian marble, and occupies very nearly the whole of the Entrance Pavilion. By reason of a partial division of the hall into stories and open corridors, and on account of the splendor and variety of the decoration everywhere so liberally applied, the eye is attracted to a number of points of interest at once. The arrangement, however, is really simple and well defined, as may be seen by looking at the plan on page 9. With the exception of a portion of the attic story and of two or three small rooms partitioned off in the southeast and northeast corners of the first floor, the entire pavilion serves as a single lofty and imposing hall. In the centre is a great well, the height of the pavilion--seventy-five feet--enclosed in an arcade of two stories, the arches of the first supported on heavy piers and of the second on paired columns. The centre of the well is left clear; on either side, north and south, is a massive marble staircase, richly ornamented with sculpture. On the east side of the pavilion a broad passageway, treated as a part of the general architectural scheme of the Entrance Hall--though really an arm of the interior cross already referred to--connects it with the Main Reading Room. =The Vestibule.=--The arcades surrounding the well, or Staircase Hall, as it would better be called, screen two stories of corridors. The corridor which the visitor has now entered--the West Corridor, on the library floor--serves as the general vestibule of the building, and appropriately, therefore, is more sumptuously decorated than any of the others. The most striking feature is a heavily panelled ceiling, finished in white and gold--perhaps as fine an example of gold ornamentation on a large scale as can be found in the country. It is impressively rich and elegant without in the least overstepping the line of modesty and good taste. The corridor is bounded by piers of Italian marble ornamented with pilasters. There are five piers on each side, those on the west terminating the deep arches of the doors and windows, and one at either end. It will be noticed that these piers, like all the others on this floor, are wider than they are deep, so that the arches they support are of varying depth--the narrow ones running from north to south, and the deeper ones from east to west, invariably. This difference of depth, both of the piers and of the arches, is apt to be somewhat bewildering until one perceives the system on which it is based, so that it may be well to add in this connection that the same rule of broad and narrow, and the direction in which each kind runs, holds good, also, of the corridors on the second floor, the only variation being that paired columns, as has already been pointed out, are substituted for piers.