Guess the President

Extra credit if you identify the writer (pictured above):

The next day after my arrival I visited the President, accompanied by some Democratic members. In a few moments after our arrival, a tall, high-boned man came into the room. He was dressed, or rather undressed, in an old brown coat, red waistcoat, old corduroy small clothes much soiled, woollen hose, and slippers without heels. I thought him a servant, when General Varnum surprised me by announcing that it was the President.