The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 9: Poetry and Eloquence.
Francis Trevelyan Miller, Ed.

‘With the mien of but a soldier in the ranks’

Here Grant's dress is nearer uniform than usual. A veteran recalls that it consisted ordinarily of a plain old army hat—‘slouch,’ as it was called—and fatigue coat, pretty well worn, with very little insignia of rank for outward show. Thus he was frequently taken by the soldiers along the line for some old cavalryman who was investigating affairs he knew nothing about. In his tours General Grant was often stopped by the guards around the camps and compelled to identify himself before the men would permit him to pass. It sometimes happened that the sentries knew the General well enough by sight, but since he was not in full uniform and bore no insignia of rank, they would solemnly compel him to halt until they could call for the officer of the guard, who would formally examine the general as to his identity.

The commander of the armies Grant in July, 1864