The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 5: Forts and Artillery.
Francis Trevelyan Miller, Ed.

[54] succession of battles and flank marches through the Wilderness to the James, up to Petersburg, thence to Appomattox, had taxed the energies and showed the devotion of the men with the guns in the hardest campaign of the war, finally causing the surrender of a remnant of the proud Army of Northern Virginia.

While at Petersburg, an interesting experiment was tried which resulted successfully. A large 13-inch Coehorn mortar was mounted on an ordinary railroad platform car, run down to a point within range of the Confederate works, and halted on a curve so that by a slight movement of the car the direction of the piece could be changed. The mortar, fired with fourteen pounds of powder, recoiled less than two feet on the car, which, in turn, was moved only ten or twelve feet on the track. The firing excited much apprehension in the Confederate works, and was effective in preventing their batteries from enfilading the right of the Union lines.

Major E. S. May, of the British army, has this to say of the Federal artillery in the Civil War:

We have not by any means exhausted that rich repository of brilliant deeds, and many bright examples are reluctantly omitted. Enough, however, has been said to show that this arm can scarcely be with justice reproached for lack of enterprise during the great struggle. . . . As regards the conduct of officers and men in action, efficient service of guns, and judicious handling on the part of its more prominent leaders, the artillery showed itself in no degree unworthy of the great traditions handed down to it from the previous era, and may point with satisfaction to what it accomplished.