In the meantime, the fog-ridden atmosphere was riven by blazes of powder from the shore guns, trained upward, and the air squadron, Zeppelins and naval seaplanes, were leaping skyward to meet their kind in aërial battle. Roque charged madly into the air station, dragging the boys after him. A seaplane was balanced on the polished ways for the sweeping plunge. "In the name of the Emperor!" he shouted, shouldering aside the men holding the poised craft. The same fierce whisper in the ear of the aviation lieutenant had effect identical with that upon the marine at the docks. "Get to your places, you moonfaces"--this stern command hurled at the boys. Henri bounced into the motor section, Billy settled behind the rudder wheel, and Roque swung himself into the bow seat. The long hull was launched with the snap of training, and with motors humming left the water without a wrench from its skimming start. The Boy Aviators, certified masters of the air, were at their trade. They had need of all their skill and daring that day! "Set your course northwest," loudly ordered Roque. "Hit for Helgoland like a bolt." "Look out that you don't hit something on the way!" shouted Henri from the rear. The last warning was timely, if Billy had need of warning at all. There was peril in the foggy stretches. The upper regions were literally lined with aircraft. No less than seven naval seaplanes had traveled in advance of the British warship invasion of the German bay. Having dropped all the bombs they could through the mist, they were in full return flight to the convoying vessels. Zeppelins and hostile seaplanes zigzagged on their trail, and other dirigibles and fighting craft menaced their retreat still further on. Billy guided the seaplane he was driving to the higher strata in order to escape mix-up with the contending airships, but on the thirtieth mile recorded, Roque, who had constantly demanded distance figures, ordered a lower flight, and, the fog clearing, the flyers could plainly see on the waves far below the floating warcraft of the invaders--light cruisers, destroyers and submarines. The Germans were combating this array with aircraft and submarines, but so great was Roque's impatience to reach the fortified island that the motors were put by Henri to the limit of speed, and so that part of the conflict is not in the record of the Aëroplane Scouts. Just off Helgoland, though, the boys had the shock of noting the crumpling of one of the British seaplanes and the end of a brave airman. "There's no escape when death stalks you up here," sighed Billy. "Ware away, boy," called Roque, when the seaplane hovered over Helgoland, "wait until they see the color of the bottom of the machine or we will look like a sieve before we light." Billy "wared away," and with motors at half speed, the seaplane circled over the supposed most impregnable stronghold in the world, awaiting some signal of recognition from the fortress.