Clara Barton autograph letter signed, responding to an invitation to lecture. Dated 15 April 1868 from Washington DC, letter reads in full, ''H.W. Clarke Esq. / Dear Sir / Your letter of the 9th inst. inviting me to lecture for Post No 7 of Syracuse is rec'd. / I regret that it will not be in my power to oblige you this season. I have travelled far and spoken much the past winter; am weary, and home to rest. Some other person can be selected who will do much better for your cause than I, and in this hope I remain. / Very truly yours / Clara Barton''. Single page letter measures 5'' x 8'', mounted to a larger sheet. Very good condition. Accompanied by a 5.25'' x 3.25'' silver gelatin photo of Clara Barton's childhood home.