13-inch sea-service mortar.
The 13-inch land mortar depicted [below] is a much more serviceable production, because it contains much less metal.
13-inch land-service mortar.
Mortars will retain their place in spite of all improvements. Rifling is inapplicable to them. Their principal utility consists in obtaining a vertical fire; the shell being pitched to a great height, so as to fall into places that cannot be assailed by a horizontal fire.