He fought in the Civil War in the 85th New York Volunteers.

Quite a number of the Eighty-fifth regiment were killed or wounded at the battle of Fair Oaks. Nathan was wounded by the bursting of a shell, a pieces striking him on the side of his head, while two of his comrades were killed by his side. He did not realize that he was wounded until daylight came, and the scattered men of the Eighth-fifth gathered in the morning. Then he was asked what was the matter with his head, as they saw the blood had been running down his back from his head. He took off his cap only to find a hole cut in his cap and quite a gash cut in his scalp. He had been so excited in the battle that he did not know he was wounded.

After the Eighty-fifth had fought nearly three years, their term of enlistment had nearly expired, the rebels surrounded them at Newbern, There was no chance of escape. They surrendered, and were all marched to Andersonville prison. There were at one time thirty-four thousand prisoners in the stockade, without shelter or a shade tree to protect them from storm or the hot sun, and without the necessaries of life. Many were starved to death. Nathan and Ethan's adopted son and a were among those that survived. They were all rather small eaters at home, and consequently could live on smaller rations.