Within the enclosures formed by these various desks and cabinets is a small elevator for bringing books by the truck-load from the basement story. The Distributing Desk itself is built of mahogany, ornamented with panelling and carving. On the east side it consists of a high station for the use of the Superintendent--the officer in charge in the Rotunda--who is thus able to keep in touch with everything doing in the room. On the other side is a cabinet containing the terminus of the system of book-carrying apparatus connecting the Reading Room and Stacks, and in the centre is a stairway leading to the basement. Along the front of the desk, also, is a row of twenty-four pneumatic tubes for the transmission of messages, either in cylindrical pouches, as in the case of the written applications which those desiring to draw books are required to make out, or verbally, by means of a mouth-piece with which each tube is equipped. Nine tubes go to the North Stack and nine to the South Stack, or one for every floor. Four go to the East Stack, or one to every other floor. An attendant for any portion of the stack system can thus be reached at a moment’s notice. Of the other two tubes, one goes to the Librarian’s Room and the other connects with the Capitol. Each tube is numbered, and is operated by pressing a button, the action of which indicates, also, when the pouch is delivered at the other end. Each tube terminates in a separate bronze case or box, which is heavily cushioned, and closed by self-shutting glass doors in order to prevent noise. The tube enters at the bottom, and the pouch is thrown against a curved “hood,” so called, which guides it to one side so that it may not fall back into the mouth of the tube. [Illustration: KENT. BY GEORGE E. BISSELL.] =The Book-Carrying Apparatus.=--The main features of the book-carrying apparatus were suggested by Mr. Green, although worked out with the assistance of ingenious mechanics. The apparatus is in two parts, each separately operated, the first of which connects with the North Stack and the second with the South Stack. The East Stack is so much less extensive than the other two that it was thought more economical to rely solely upon the services of the attendants for the delivery and return of the books it contained. Each section of the apparatus (north or south) consists of a pair of endless chains kept continuously in motion, at the rate of about one hundred feet a minute, by means of power furnished by an electric dynamo. These two chains run from the terminal cabinet to the basement; thence on a level to the stacks; and from there directly up a small well to the top floor, where they turn and descend.