ut one example
out of a hundred: his guns would be always unlimbering, shooting at
you, then limbering up again to continue the pursuit; unlimbering
again, shooting again--and so forth; while your guns would never
reply, being occupied in an unbroken retirement, and therefore
continually limbered up and useless behind their teams.

A retiring force, therefore, of whatever size--from a company to an
army--can only safely effect its retirement by detaching one fraction
from its total which shall hold up the pursuit for a time while the
main body gets away.

When this detached fraction is wearied or imperilled, another fraction
relieves it, taking up the same task in its turn; the first fraction,
which had hitherto been checking the pursuit, falls back rapidly on to
the main body, under cover of the new rearguard's fire as it turns to
face the enemy. And the process is kept up, first one, then another
portion of the whole force being devoted to it, until the retirement
of the whole body has been successfully effected, and it is well ahead
of its pursuers and secure.

[Illustration: Sketch 47.]

For example: two White army corps, I., II., as in the annexed diagram,
each of two divisions, 1, 2, and 3, 4, have to retire before a greatly
superior Black force, _abcde_. They succeed in retiring by the action
expressed in the following diagram. White corps No. I. first
undertakes to hold up the enemy while No. II. makes off. No. I.
detaches one division for the work (Division 2), and for a short time
it checks the movement of _a_, _b_, and _c_, at least, of the enemy.
Now _d_ and _e_ press on. But they cannot press on at any pace they
choose, for an army must keep together, and the check to _a_, _b_, and
_c_ somewhat retards _d_ and _e_. They advance, say, to the positions
{~GREEK SMALL LETTER DELTA~}{~GREEK SMALL LETTER EPSILON~}.

[Illustration: Sketch 48.]

Next, White corps No. II. stops, puts out one of its divisions (say 4)
to check _d_ and _e_, while its other division either helps or falls
back, according to the severity of the pressure, and White corps No.
I. makes off as fast as it can. _a_, _b_, _c_, no longer checked by a
White rearguard, are nevertheless retarded from two causes--first,
the delay already inflicted on them; secondly, that they must not, if
the army is to keep together, get too far ahead of their colleagues,
_d_ and _e_, which White corps II. is holding up.

[Illustration: Sketch 49.]

Thus,