are dangerous
companions. Thirteen-inch carcasses weigh 194 pounds each.

477. Bombs are sometimes fired with a port fire stuck into the
fuze-hole, which is an almost certain mode of igniting many kinds of
buildings.

478. Mortars can also be fired with a bag of one-pound balls, or
ordinary grape-shot, with very reduced charges, and a wad between the
powder and the balls. One pound of powder will project a 200-lb. bomb
302 yards; the same weight of grape-shot thrown in among boats would
prove destructive; and especially a lot of canister fired in this
manner would cause great havoc.

479. It is not expected, however, that much execution could be done
after the first discharge in a fleet of boats moving rapidly; but
combined with the batteries of the Squadron, it is presumed that an
enemy would be deterred from an attempt to capture a vessel by
boarding.

TAKING THE DISTANCE.

480. An inexperienced officer will find difficulty in estimating
distances by the eye alone, as it requires long practice and studied
observation. The sextant, however, offers a surer method of
approximately fixing a position by taking the angles between any three
points, which are generally found to be accurately laid down on the
Coast Survey charts; then plotting the angles with a horn protractor,
or working them out by the three-point problem, which is given in all
surveying books.

481. If the object to be assaulted is a large one, a practical man
can, by the exercise of moderate judgment after two or three fires,
throw the bombs near the work; but, at the same time, the sextant is
the more certain means for determining the true distance, and the
Officer in command should make himself acquainted with the simple
manner of measuring horizontal angles.

482. If points are not visible in line, then measure a base on shore,
angle on the object to be aimed at, and from the angles of the
base-line, you can fix the position of the mortar-vessel.

483. When a vessel once gets her position accurately determined, and
it becomes necessary after a bombardment to remove out of the line of
battle, a small buoy with the vessel's name or number should be
dropped under foot, so that the same position may, if necessary, be
resumed.

LOADING MORTARS.

484. After the powder has been emptied through the funnel out of the
cotton bag into the chamber, the bomb, loaded and fuzed, is to be
carefully lowered into the bore by the hooks, and allowed to