TLS signed “C. A. Lindbergh,” one page, 8.5 x 11, personal letterhead, May 26, 1930. Letter to Miss Gladys M. Wrigley, editor for the American Geographical Society, in part: "Lack of time prevents me from checking over proofs but any article that is satisfactory to the Carnegie Institution is satisfactory to me." In fine condition, with some light corner creasing. Encapsulated and graded by PSA/DNA as “MINT 9.”