The unit that has pushed farthest to the front must facilitate with its fire the advance of those who have encountered greater obstacles in advancing.
Long, dense firing lines and the supports following them are exposed to such heavy losses in open country, even at long ranges, that their advance will soon hesitate. Moreover, the defender will only fire on targets whose size and density promise a great number of hits. Therefore, the assailant should endeavor to lead his infantry forward in loose, disconnected skirmish lines, which are difficult for the enemy to hit. As a rule, the assailant should not open fire until after he has been reinforced and has sufficient fire power available. (Par. 334 German I. D. R.). The situation in which these thin firing lines are placed is by no means a favorable one, as the defender will concentrate his fire on the points where the assailant seems to be filling up his line "for the purpose of overwhelming the defender permanently by a superiority of fire." (Par. 413 German I. D. R.). The skirmishers will then quite naturally open fire for the purpose of interfering with the cool delivery of the defender's fire.
Such a piecemeal, almost independent advance, during which the effect of the accustomed word of command is considerably reduced and control and supervision of the individual skirmisher is impossible, presupposes that the troops are well-drilled, individually trained, and, above all, intelligent. Attention must also be called to the fact that the firing line can offer but a weak resistance to an enemy advancing unexpectedly in force. But, in spite of these drawbacks, this mode of advance has its advantages for crossing a plain devoid of cover. It permits favorable fire positions to be reached with greater safety, especially if these positions can be picked out with the aid of field glasses, than would be the case if dense skirmish lines were led forward simultaneously.
The advance of the infantry under hostile fire, over open ground, may accordingly be conducted—
