Great find! I hadn't realized they were playing with illumination rounds for the mortars as well as corrugating the insides of the shells to make them burst more effectively. Nice line drawing of the 13" Seacoasts at Yorktown too... looks like it could have been drawn from the famous photograph.
Brings home even more how the Civil War was the test-bed for WWI. On a tour of the Fredericksburg works (Marye's Heights, Sunken Road), the guide noted that a lot of European observers came over to study how the improvements in firearms changed the traditional old marching-around-in-lines tactics into trench warfare.