_DISPART._—The dispart of a gun is the half difference between the
diameter of the gun at the base ring, and at the swell of the muzzle.
The general dispart of all guns is about the ¹/₅₆ part of their length.
See the disparts of French and English guns under the word _Tangent
Scale_.
[Illustration: _Fig. 1._]
_DISTANCES._—Inaccessible distances may be found several ways; the
most correct of which of course is by means of proper mathematical
instruments; which, however, are not always to be had in the field.
The following different methods are laid down by several authors, where
instruments cannot be had.
I. Wishing to know the distance of the object A from B—(fig. 1.) place
a picket at B and another at C, at a few fathoms distance, making A
B C a right angle, and divide B C into 4, 5, or any number of equal
parts: make another similar angle at C, in a direction from the object,
and walk along the line C D till you bring yourself in a line with the
object A, and any of the divisions, (say _o_) of the line B C. Then, as
C_o_ : CD :: B_o_ : BA.