Book Excerpt: ...as I can remember: He come a-loping into Washington, and put up his horse and shoved out to the President's house with his letter, and they told him the President was up to the Capitol, and just going to start for Philadelphia -- not a minute to lose if he wanted to catch him. Nat 'most dropped, it made him so sick. His horse was put up, and he didn't know what to do. But just then along comes a darky driving an old ramshackly hack,...