nes, convoys, or reinforcements. In a word, by
adopting the maxim, that the _enemy must be made to pay for whatever he
gains_, it disputes with him every inch of ground, and if at last it
yields to him a victory, it is of that kind which calls forth only his
sighs."

In discussing the subject of strategy, certain technical terms are
employed, such as _theatre of war; theatre of operations; base of
operations_, or the line from which operations start; _objective
points_, or points to which the operations are directed; _line of
operations_, or the line along which an army moves; _key points_, or
points which it is important for the defensive army to secure; _line of
defence,_ or the line which it is important to defend at all hazards:
and in general, _strategic points, strategic lines, strategic positions,
&c._ As these terms are very generally used in military books, it may be
well to make ourselves thoroughly acquainted with their import. After
defining these terms and explaining their meaning and application, it is
deemed best to illustrate their use by reference to well-known and
striking historical examples.

_The theatre of a war_ embraces not only the territory of the two
belligerent powers, but also that of their allies, and of such secondary
powers as, through fear or interest, may be drawn into the contest. With
maritime nations it also embraces the seas, and sometimes crosses to
another continent. Some of the wars between France and England embraced
the two hemispheres.

_The theatre of operations_, however, is of a more limited character,
and should not be confounded with the theatre of war. In general, it
includes only the territory which an army seeks, on the one hand, to
defend, and on the other, to invade. If two or more armies be directed
towards the same object, though by different lines, their combined
operations are included in the same theatre but if each acts
independently of the others, and seeks distinct and separate objects,
each must have its own independent theatre of operations.

A war between France and Austria may embrace all Italy and Germany, but
the theatre of operations may be limited to only a portion of these
countries. Should the Oregon question lead to hostilities between the
United States and England, the theatre of war would embrace the greater
part of North America and the two oceans, but the theatre of operations
would probably be limited to Canada and our northern frontier, w