Shortly afterwards the air service boys received word to start, and along with four other planes mounted upward like birds on the wing.
So far as appearances went the scene below them did not differ materially from the preceding day. There was the same vast stretch of grim forest known as the Argonne, with occasional openings here and there, "breathing spots," they might be called. These marked sites of farms, timber or cutting authorized at some past day by the French government, that controlled the wonderful tract of woods, possibly the largest in all France. Smoke was already rolling upward in great volumes while the air pulsated with the fearful crash of every imaginable type of gun, both large and small. As the day wore on all this was bound to increase greatly, the impetuous Americans pushing forward and wresting rod after rod of the forest from the enemy, paying the price without a murmur, but grimly determined.
Jack having attained the required altitude commenced "fishing." That was his way of describing the means employed for learning where the Huns were lying in wait, ready to pour in a deadly machine-gun fire on the first detachment of Yankees that came along.
The darting plane would dive down close to the tops of the tall trees, and thus offer such a tantalizing bait that the concealed Hun gunners, unable to resist the temptation, were likely to shoot at the cruising machine.
Of course this would expose their secret hiding-place, but inaccurately located in the darkness the night before, and it was the business of the observer to signal his discovery back to those who were on the watch.
The consequence would be that instead of making a frontal attack on that particular nest, the infantry would resort to Indian tactics, making a flank movement that would carry them past, then closing in from the rear. At a given signal some of their mates would make a hostile demonstration in front to chain the attention of the gunners, while others would creep up so close from the rear that they would be able to get both men.
Of course this meant that the venturesome fliers would be taking additional risks. When that machine-gun should start to pepper their plane they were likely to be struck by one or more of the shower of missiles coming hissing up like enraged hornets. What matter, when they were accepting chances just as desperate every minute of the time they remained aloft?
Jack and his assistant, Morgan, found themselves busily engaged inside of ten minutes. They swooped so low that suddenly there was a burst of fire, and bullets commenced to cut through both wings of their plane. The body had been sheathed in metal that would serve to ward off most of this hail, but despite this they took many chances of a mishap.
Immediately Morgan noted the exact spot from which the firing came, so he could locate it in sending out his signal of warning. Jack meanwhile was doing his part, dodging in zigzag curves in all directions in order to baffle the aim of the Hun gunners.
Then, too, the trees helped greatly to conceal them from the observation of the enemy below; so that the firing kept up for a very brief time only. But their trick had succeeded. The Boches dared not come out from their place of concealment lest they be discovered and shot down by the stealthily advancing Americans. Perhaps they were even chained there, as frequently happened.