This primary source comes from the Records of the Office of the Chief Signal Officer.
National Archives Identifier:
528217Full Citation: Gen. Ulysses S. Grant; ca. 1860 - ca. 1865; Mathew Brady Photographs of Civil War-Era Personalities and Scenes, 1921 - 1940; Records of the Office of the Chief Signal Officer, Record Group 111. [Online Version, https://docsteach.org/documents/document/1-gen-ulysses-s-grant, December 10, 2024]