Thursday, February 20. — I went to Washington to-day in an ambulance, with Sam and Michael and one of the telegraph operators. We went on the corduroy road, and such riding I never felt in my life before, the wagon creaking and shaking in every joint, and I myself feeling as if I were doing the same. Up two or three feet in the air at one moment, and down again the next. Driving in the mud compared with it is like the difference between riding in a carriage and in a tip-cart. I went in to get some things for Captain Norton,[1] and to have my photograph taken. I think I have a very good proof, but shall not get it till Monday. The day was chilly, and a blanket thrown over my knees was a welcome protection. When I came out here I found that General McClellan and staff had been here, and in fact were here, for I reached camp just in time to see them mount and ride off. I am sorry I was not here, as I should have liked to be introduced to McClellan. I had a small tent placed before mine as an entrance. Quite an improvement.