In order to find the answer to your question, we can refer to the novel "The Red Badge of Courage" by Stephen Crane. One way to determine the color of the uniforms of the Northern army is by reading the description of the soldiers in the book. By observing the descriptions provided by the author, we can find clues about the colors used for the uniforms. Additionally, analyzing historical context and knowledge about the American Civil War can help in determining the color of the Northern army's uniforms.
The uniforms of the Northern army (with whom Henry fought) in The Red Badge of Courage were blue.
