Their sergeant was telephoning hurriedly as to what was happening:
"Airplane motors close overhead. No bombing yet. Watch out."
Thus it happened that Bauer's first (and last) signal was rendered void insofar as it went. The raiders escaped the German fire for the time being. Moreover, they were puzzled. Why should the Allied "schwein" fly so low, yet do no harm where once they had wrecked things only a few days before? What were they up to, anyhow?
This query was not answered at once. The telephones roused the Huns in the front trenches. Yet it puzzled them, too. Hitherto the bombing on both sides had been done mostly from far above. Such skimming the ground across No-Man's-Land might mean anything.
Presently the thrum of approaching planes became more and more audible along that portion of the front.
From his plane Blaine made private signal to the others to put on all speed. Erwin did likewise. Consequently it was not a minute before the raiders were upon the front trenches, going at the rate of two miles a minute. Each man in those planes sat with an open nest of hand grenades within easy reach. The handle of the gun crank was handy, its deadly muzzle pointed along the top of the fuselage of each mobile plane.
Then a pistol shot rang out, and at the signal grenades were dropped as the now far extended line passed over those open trenches in which troops were massed. For, be it known, that fatal blue flare from the aerodrome a dozen or more miles away had filled those trenches yet more full of human cannon fodder. Hence the bombing was all the more deadly.
Passing the trenches, at another signal, the hostile planes nimbly wheeled, shot back again and poured forth more bombs upon those trenches. Still again they wheeled and traversed them for the third time.
By this time machine guns began to spatter their deadly contents among the darting planes, while further back the anti-aircraft guns gave forth searching roars as to what they might should a plane be hit.
It was enough so far as it went. Now for the gas-bags, the sausages; for these observation balloons were the real object of all this nocturnal pother.
"Forward!" came the signal again and, steering to the left, rising higher from the forty to fifty foot level they had hitherto kept, the squadron made for the rear line. Here rose a shadowy line of oval bags, so shaped as to qualify them for the term "sausage" as humorously fitted to these defenseless spying observatories. In daytime their elevation enabled them to see over a great expanse of that level, war-ruined region.