This section is from the book "The National Capitol. Its Architecture Art And History", by George C. Hazelton, Jr. Also available from Amazon: The National Capitol Its Architecture Art and History.
The clock above the door which leads to the rotunda was carved from a solid piece of marble by Franzoni, and commands admiration for its beauty. Clio, the Muse who presides over History, standing in a winged chariot, records the passing events of the nation upon tablets. The wheels indicate the flight of time as the car rolls over a globe, which is encircled by a belt whereon are chiseled the signs of the zodiac. This artistic bit was carved in the Capitol at a per diem compensation. Its cost is unknown. Behind the clock runs a semi-circular gallery, once occupied by wealth and fashion, but now the depository of hundreds of dusty, rarely-read volumes.