is obvious that by this arrangement the books can be more easily reached than in any other way. The axes of the stacks are continued radii of the Rotunda, and, so far as the ground plan is concerned, the shortest way from any part of the cross to the Distributing Desk which the visitor sees below in the centre of the room is always along a straight line. This Distributing Desk, of course, being in the exact centre of everything, is the vital point, the kernel, of the whole arrangement. No part of the stack, it will be noted, is far enough away from it to delay the transmission of a book unreasonably, as might very well be the case if the three stacks were in one. Moreover, by the use of a mechanical contrivance, which will be explained later, even this distance is in effect very greatly reduced. [Illustration: THE GALLERY OF THE ROTUNDA. SHOWING THE STATUES OF HERODOTUS AND BEETHOVEN.] Another thing may well be noted in this connection although it has already been referred to in the preliminary description of the building--and that is, the comparative unimportance, from the standpoint of the real requirements of the Library, of the great Rectangle which encloses the stacks and the Rotunda, and necessarily appears from the street to be the main portion of the building. It contains rooms which, at present, are very convenient for clerical work or as art galleries and special reading rooms, and which may in time be necessary to accommodate an overflow of books; but it must steadily be borne in mind that the Rotunda and the stacks contain the real life of the institution. They are the only really essential and vital portion of the building; without them, there could hardly be a library; and by themselves they would be sufficient for almost every present need.