and Southern Armies. By skilful reinforcement of threatened points, Marshal Haig frustrated the primary object of the attack, and by the aid of the French Armies the whole line fell back, disputing the ground with the utmost resolution, and maintaining the line without losing touch between the south and north. The German wedge was thrust in, but every attempt to effect a breach and to pour through the line was frustrated by the Allies. During the battle the French and British Armies became intermingled, and to preserve unity of control a Generalissimo was appointed in the person of General Foch, who had commanded the French IX. Army at the First Battle of the Marne in September, 1914, and the French Armies of the Somme during the advance in July, 1916. General Pershing, commanding the Army of the United States, gave a free hand to the Generalissimo to incorporate American troops wherever they might be needed in the field, and Marshal Haig and General Retain remained in command of the British and French Armies. METHODS OF ATTACK.--The object of every attack is to break down the enemy's resistance by the weight and direction of fire and to complete his overthrow by assault, by the delivery of a decisive blow with as large a portion as possible of the attacking force against a selected point or portion of the enemy's position. The term "Decisive Attack" does not imply that the influence of other attacks is indecisive, but rather that it is the culmination of gradually increasing pressure relentlessly applied to the enemy from the moment when contact with him is first obtained. {54} TWO PLANS OF ATTACK.--There are two plans of attack. In the first, the direction in which the decisive blow is to be delivered is determined beforehand; an adequate force is detailed and pushed forward for this purpose, and at the same time another part of the force is detailed to attack another portion of the enemy's position, to keep his attention there, to pin his troops in position, to prevent him sending reinforcements to the part mainly threatened, and ultimately to drive home with the successful assault of the main attack. The rest of the force is small and is retained in General Reserve to meet emergencies. In the second plan, a general action is developed by a part of the attacking force and the remainder is retained in General Reserve, to be thrown in when the opportunity arrives, at the right time and in the right place. In this case, the "remainder" is not less than half the available force.