are attached to each unit engaged and to its headquarters. Higher
units than battalions can usually depend on the Signal Service for
intercommunication, but whenever necessary, a supply of runners and
mounted orderlies must be available for their use. This ensures
co-operation, and enables mutual support to be rendered. Information
received must be transmitted at once to all whom it concerns, and
orders received from superiors must be communicated without delay to
commanders of all units affected.

CO-OPERATION.--"Co-operation when in contact with the enemy is no easy
matter to bring about. There are, however, three means of overcoming
the difficulty: constant communication between the units; thorough
reconnaissance of the ground over which the movements are to be made;
clear and well-considered orders" ("The Science of War"). Each
commander who issues orders for Attack or Defence should assemble his
subordinate commanders, if possible in view of the ground over which
the troops are to operate, explain his orders, and satisfy himself that
each subordinate understands his respective task. "Combination depends
on the efficiency of the chain of control connecting the brain of the
commander through all grades down to the {36} corporal's squad; on the
intelligence of subordinate leaders in grasping and applying the
commander's plans; on the discipline which ensures intelligent
obedience to the directing will; and on the mobility which gives rapid
effect to that will, and permits advantage to be taken of fleeting
opportunities. Every fresh development in the means of transmitting
orders and information rapidly, permits of an extension of the
commander's influence, and makes more perfect combination possible and
over wider areas" (General Sir E. B. Hamley). Even when, and
particularly when, forces are engaged in battle, reconnaissance must be
carried on and information gained must be communicated at once. It
will frequently happen that a suitable moment for the decisive attack,
or decisive counter-stroke, will be found only after long and severe
fighting. Systematic arrangements for obtaining, sifting, and
transmitting information throughout the battle are therefore of the
highest importance. Information must be gained not only by troops and
aircraft actually engaged, but by supports and reserves, who will often
be able to see what is invisible to the forward troops. In such cases,
more than in any other, informati