CLEMENS, SAMUEL ("Mark Twain"). Autograph letter signed ("S.L. Clemens") to Mr. E. A. Reynolds Ball. Hotel Royal, Berlin, 22 February [18]92. One page, 8vo, brown ink on plain bond, folded horizontally for mailing; some light creasing to edges; with postmarked envelope, addressed in Clemens's hand. Clemens belatedly acknowledges the receipt of a text by Ball, and refers to a recent period of convalescence: "...I am just out of bed after a 38-days' (sic) illness, and am ordered to the Riviera for restoration. Meantime your book has arrived, and furnishes me just the information I needed..."