4. Where a ravine, a wood, or other similar obstacle causes _a break in our line of battle_, by occupying it with skirmishers we guard it against penetration by the enemy, and connect the separated corps with each other. 5. Skirmishers may be used to alarm the enemy at a point where he expected no attack, and thus _create a diversion_. 6. By their attack at various points, they serve to _unmask the enemy's position_. 7. They may be employed to _open the way for a charge_ with the bayonet. At the battle of Stone River, the rebels, on one occasion, advanced in line, with a double column in rear of each wing, preceded by a double line of skirmishers, who reserved their fire till close to our line, when they halted, poured in a murderous fire, and fell back on their main body, which then rushed forward. Both our first and second lines, staggered by this sudden and destructive fire, were swept from the ground. 8. Skirmishers have been sometimes thrown forward to _test the spirit and disposition_ of the enemy. At Biberach, in 1800, the French general St. Cyr, after having carried the place, and driven the Austrians through the defile in rear of it back upon their main body, posted on the heights of Wittenburg, sent forward a strong line of skirmishers to open fire on them, with the view of ascertaining their temper and disposition after their vanguard had been defeated and driven in. This drew forth a general and continued discharge, like that which demoralized troops are apt to indulge in to keep up their spirits by their own noise. Seeing this, St. Cyr instantly prepared to charge, although he had with him but twenty thousand men, and the Austrians numbered sixty thousand, and were in a strong position. The result justified his decision; for, on the near approach of the French, the Austrians fired a volley or two and then retreated in confusion. 9. Skirmishers should _accompany columns of attack_; for-- (1.) They increase the confidence of the troops they accompany. Placed between the columns, they advance boldly because the columns advance, and the columns advance boldly because the skirmishers do. (2.) Preceding the columns, by driving back the enemy's skirmishers, and diverting his fire to themselves, they keep the attacking columns as free from loss as possible till the shock. They, moreover, serve to annoy the troops we are about to attack, by the incessant sharp buzzing of their deadly bullets among them, like so many bees, killing some and disabling others; and this, sometimes, to such a degree as to demoralize them. It is said that, at Waterloo, the swarms of skirmishers that covered the French attacking columns so galled and excited the stationary columns and squares of some of the Allies, as to nearly drive them from the field. (3.) On the flanks of a column, they cover them from attack. (4.) They draw the enemy's fire prematurely, and thus render it comparatively ineffective.