This primary source comes from the Records of the Office of the Chief Signal Officer.
National Archives Identifier:
528323Full Citation: Abraham Lincoln President, United States, and Cabinet; ca. 1860 - 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/abraham-lincoln-president-united-states-and-cabinet, March 28, 2023]