_Para. 2._--Surprise is a powerful factor in the effective employment of the machine gun; every effort must therefore be made to avoid the enemy’s observations both when advancing to a position and when in action. The machine gun possesses the power of delivering, from a very narrow front, a practically uninterrupted volume of closely concentrated rifle fire, which can be directed against any desired object with the least possible delay. The delivery of such fire cannot, however, be long sustained, because of the heavy expenditure of ammunition involved and the difficulty of replacing it. It is necessary, therefore, for its effective use, that its movements and fire action should be so regulated as to enable it to open fire rapidly whenever a favourable target presents itself, for the losses inflicted on an enemy will affect him in proportion to the suddenness and rapidity with which they are experienced. As the rôle of machine guns is to assist the particular body of troops to which they belong, the machine-gun commander should be fully acquainted with the orders issued to such troops. He should also carefully watch and conform to their movements, and assist them by every means in his power. As a rule the guns belonging to a unit will be employed singly in order to obviate the concentration of hostile fire against them, the most favourable position being sought for each weapon with regard to fire effect and cover; this, however, should not prevent the guns being used together when the circumstances of the moment demand the adoption of such a course. The massing of guns should be rarely resorted to. When it is desired to bring an overwhelming fire to bear on any locality, it should be accomplished by the concentration of fire from dispersed guns. The selection of a fire position should be preceded by careful reconnaissance on the part of the machine-gun commander. The following points should be looked for: (_a_) A good field of fire. (_b_) Concealment. (_c_) Cover from the hostile fire. (_d_) Possibilities for advancing to the position unobserved, and facilities for ammunition supply. (_e_) Security against a covered hostile approach.