The movement in a succession of thin lines is used to cross a wide stretch swept or likely to be swept by artillery fire or heavy long-range rifle fire which can not profitably be returned. Its purpose is the building up of a strong skirmish line preparatory to engaging in a fire fight. This method of advancing by thin lines results in serious, though temporary, loss of control over the successive platoons of the troop. Its advantages lie in the fact that it offers a less definite target, hence is less likely to draw fire. =653.= These are merely suggested methods of advancing preliminary to opening the fire attack; other formations better adapted to particular occasions or terrain may be devised. The best formation is that which advances the line the farthest without drawing the enemy's fire, or, if he does open fire, then with the least loss of men, time, and control. THE FIRE ATTACK. =654.= The principles involved in the fire attack are discussed under =Dismounted Fire Action, the Squadron= (par. 716), and necessary modifications as to details made under =Dismounted Action, the Regiment= (par. 760). When the enemy's fire makes it impracticable for the troop to move forward in one of the above-mentioned formations, it may advance by rushes. Being in skirmish line: 1. =By platoon (section) from the right (left)=, 2. =RUSH.= The platoon leader on the indicated flank arranges the details for a prompt and vigorous execution of the rush and puts it into effect as soon as practicable. If necessary he designates the leader for the indicated unit. When about to rush he causes the men of the indicated unit to suspend firing and to hold themselves flat on the ground but in readiness to spring forward instantly. The leader of the rush (at the signal of the platoon leader if the latter is not the leader of the rush) commands, =Follow me=, and, running at top speed, leads the fraction to the new line, where he halts it and causes it to open fire. The leader of the rush selects the new line if it has not been previously designated. The first fraction having established itself on the new line, the next like fraction is sent forward by its platoon leader without further command from the captain, and so on, successively, until the entire troop is on the line established by the first rush. The men must be trained to lie perfectly still until the command (since any movement might warn the enemy of the rush to follow), then at command to spring instantly and together to their feet, run at top speed, and drop together at command. =655.= In an advance by rushes, leaders of platoons in firing positions are responsible for the delivery of an effective fire to cover the advance of each rushing fraction. Troops are cautioned so to fire as not to endanger the flanks of advanced portions of the firing line. The husbanding of ammunition for the final stages of the fire attack must be constantly impressed on the men.