DEAR SIR, Your favor of Jan. 25th is received, and in reply, I will say that I accede to your several propositions, viz: That I furnish to the American Publishing Company, through you, with MSS sufficient for a volume of 500 to 600 pages, the subject to be the Quaker City, the voyage, description of places, &c., and also embodying the substance of the letters written by me during that trip, said MSS to be ready about the first of August, next, I to give all the usual and necessary attention in preparing said MSS for the press, and in preparation of illustrations, in correction of proofs--no use to be made by me of the material for this work in any way which will conflict with its interest--the book to be sold by the American Publishing Co., by subscription--and for said MS and labor on my part said Company to pay me a copyright of 5 percent, upon the subscription price of the book for all copies sold. As further proposed by you, this understanding, herein set forth shall be considered a binding contract upon all parties concerned, all minor details to be arranged between us hereafter. Very truly yours, SAM. L. CLEMENS. (Private and General.) I was to have gone to Washington tonight, but have held over a day, to attend a dinner given by a lot of newspaper Editors and literary scalliwags, at the Westminster Hotel. Shall go down to-morrow, if I survive the banquet. Yrs truly SAM. CLEMENS. Mark Twain, in Washington, was in line for political preferment: His wide acquaintance on the Pacific slope, his new fame and growing popularity, his powerful and dreaded pen, all gave him special distinction at the capital. From time to time the offer of one office or another tempted him, but he wisely, or luckily, resisted. In his letters home are presented some of his problems. ***** To Mrs. Jane Clemens and Mrs. Moffett, in St. Louis: 224 F. STREET WASHINGTON Feb. 6, 1868. MY DEAR MOTHER AND SISTER,--For two months there have been some fifty applications before the government for the postmastership of San Francisco, which is the heaviest concentration of political power on the coast and consequently is a post which is much coveted., When I found that a personal friend of mine, the Chief Editor of the Alta was an applicant I said I didn't want it--I would not take $10,000 a year out of a friend's pocket. The two months have passed, I heard day before yesterday that a new and almost unknown candidate had suddenly turned up on the inside track, and was to be appointed at once. I didn't like that, and went after his case in a fine passion. I hunted up all our Senators and representatives and found that his name was actually to come from the President early in the morning.