Reconnaissance during battle has been dealt with under "Influences on
the Battle" and in other lectures, and owing to the close connection
between the two subjects a number of points concerning reconnaissance
in general have been noted in dealing with Protection. It has also
been seen that observation by Aircraft, Patrols, and Sentries is
essential to Protection both in Position Warfare and the War of
Manoeuvre, and that Reconnaissance is the essence of Protection. There
remain, however, two forms of Reconnaissance that have not yet been
considered, namely: the Reconnaissance of a Position with a view to
attacking it, and the Reconnaissance of an unoccupied position with a
view to occupying it for defence.
RECONNAISSANCE FOR ATTACK.--The first of these is the constant duty of
all commanders in the line during Position Warfare, and it is carried
out by Patrols and Raiding Parties, who provide information which
supplements the photographs and reports of the Air Service, and enables
a commander to arrive at a decision. In a War of Manoeuvre
reconnaissance by the Air Service is equally important, and it is
supplemented by the work of the Patrols of the Advanced Guard, but
principally by that of specially selected Intelligence Officers,
working in conjunction with, or independent of, the Vanguard. Such
officers would be in possession of information which it might not be
possible to reveal to the commander of the Patrols of the Vanguard, and
their special training would give an added value to their report. The
chief {142} points to be ascertained concerning a hostile position
are:--