Machine guns, by reason of their concentrated fire and shallow beaten zone, are peculiarly suited for compelling troops to deploy at long range. They are also suited for quickly taking up a defensive position, and, when mobile, can instantly cease fire and move off in a few moments with considerable rapidity.
Their power for suddenly developing an intense fire will enable them quickly to overwhelm an enemy caught "emerging from a defile or difficult country." It would appear therefore that the machine guns are far more fitted than infantry to perform the duties of a rear guard as quoted above.
"The first consideration in selecting a position for the artillery is that it shall be able to open fire on an enemy at long range, and thus compel his infantry to assume an extended formation at the greatest possible distance. The second is that it should be possible to withdraw without difficulty."[A]
When the infantry arrive within effective rifle range of the artillery, the latter will be compelled to retire, especially if the former are supported by cavalry. This will also be the moment when the infantry will require to retire to a fresh position in rear. Machine guns that have been well concealed, or which have taken up fresh positions in good cover in rear of the infantry line, should be able to unmask and by their fire hold off the enemy until both guns and infantry have effected their retreat. The facility
