John D. Billings, Hardtack and Coffee: The Unwritten Story of Army Life

[58] others were dug down after the manner of a cellar kitchen; but all of them were at best damp and unwholesome habitations — even where fireplaces were introduced, which they were in cool weather. For these reasons they were occupied only when the enemy was engaged in sending over his iron compliments in the shape of mortar-shells. For all other hostile missiles the breastworks were ample protection, and under their walls the men stretched their half-shelters and passed most of their time in the summer and fall of 1864, when their lot was cast in that part of the lines nearest the enemy in front of Petersburg.

A mortar is a short, stout cannon designed to throw shells into fortifications. This is accomplished by elevating the muzzle a great deal. But the

A 13-inch mortar.

higher the elevation the greater the strain upon the gun. For this reason it is that they are made so short and thick. They can be elevated so as to drop a shell just inside a fort, whereas a cannon-ball would either strike it on the outside, or pass over it far to the rear.

Mortars were used very little as compared with cannon. In the siege of Petersburg, I think, they were used more at night than in the daytime. This was due to the exceeding watchfulness of the pickets of both armies. At some periods in the siege each side was in nightly expectation of an attack from the other, and so the least provocation — an accidental shot, or a strange and unusual sound after dark — would draw the fire of the pickets, which would extend from the point of disturbance all along the line in both directions.