they moreover enable their own force to get away from the enemy and to escape pursuit. [300] This applies particularly to machine guns which have air cooled barrels. After four minutes of continuous fire, part of the projectiles, and after seven minutes all of the projectiles fired from a Hotchkiss machine gun go over the target (platoon). _Kriegstechnische Zeitschrift_, January number, 1907. In employing machine guns in defense, it must be borne in mind that the guns are not adapted to carry on protracted fire actions; and that the advantage of the mobility of machine gun batteries cannot be properly utilized if they have been assigned, from the outset, a definite section to defend. As a rule, it will be advisable, in defense, to keep the machine guns at first with the reserve, and to employ them later, as necessity requires, even by platoons, to reinforce the defensive line at threatened points, or, by battery (company), to prevent an envelopment, or to participate in offensive movements. This does not preclude the employment of machine guns during the preparatory stage of the engagement, for example, to command important approaches. When a covered withdrawal of the guns is assured, it will also be possible to post machine gun batteries in such a manner in front of, or to a flank of the main defensive position, that they can suddenly sweep with their fire the ground on which the opponent will probably place his artillery. Flanking machine gun fire can sometimes be employed for sweeping dead angles. The provisions of the Austrian machine gun regulations correspond in the main to those of the German Army. In Austria special stress is laid upon the use of machine guns with cavalry, while in Germany they are in addition a mobile reserve. Machine gun batteries accomplish the principal objects which cavalry expects to attain by the assignment of infantry,[301] viz., relief from fighting on foot, great fire power, and mobility. Even in reconnaissance duty, machine guns will be employed to break down the resistance of the enemy in occupied localities and to augment the resistance of their own force in such places. During an advance, machine guns should go into position at an early moment in order to cover as effectively as possible the approach and the deployment for attack. It is advisable to post the guns of a machine gun battery together, so as not to have numerous lines of fire interfere with the movements of the cavalry; this is especially emphasized by the Austrian regulations. Machine gun batteries, like horse batteries (artillery), remain with the cavalry divisions during a battle. [301] In regard to the employment of machine guns in the maneuvers of 1905, see _Streffleur_, 1906, May number.