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.
Before the principal entrance to the Senate Chamber runs east and west the main corridor of that wing. To the south of its eastern archway is a portrait of Washington by Gilbert Stuart, and to the north, one of John Adams,copied by Andrews from the same master for a companion picture, and bought by the government for $150 in 1881. A corresponding archway, upon the right and left of which hang portraits, one of Thomas Jefferson by Thomas Sully and the other of Patrick Henry * by Matthews, connects this south corridor of the Senate with one on the west, which leads to the Italian marble staircase. This ascends to the galleries, from which visitors may view the proceedings of the Senate, except in case of executive session, when the upper corridors and all doors to the chamber and galleries are strictly guarded.