"Hang it all!" muttered the flight-sub as he actuated the rudder-bar and tilted the ailerons in order to check a cross-drift and to increase the altitude. "It's getting jolly misty. Hope it doesn't mean fog." The rearmost of the rest of the air-squadron was now almost invisible, the others entirely so. As a matter of precaution Barcroft took a hurried compass bearing, fervently hoping that the mist would clear by the time he reached his desired objective. "We're odd man out, old bird!" he shouted through the voice-tube. "Keep your eyes skinned. I don't want to get out of touch with McKenzie if it can be avoided." "It can't," replied his observer. "He's just been swallowed up by the mist." "I'll climb higher still," decided Billy. "There must be a limit to this rotten patch of vapour." For another ten minutes Barcroft held on his course. He could not be far from land, he decided. Already the leading raiders must have achieved their object, if it were possible to see their target, and were on their return journey. The chances of a collision in mid-air with one of the British seaplanes suggested itself. The idea was not an inviting one--the impact of two frail and swiftly moving objects at an aggregate rate of nearly two hundred miles an hour, and the sickening crash to earth. There would be some satisfaction in knowing that an enemy aircraft was destroyed in this fashion, but the possibility--remote, no doubt--of sending one's fellow airmen and oneself to instant destruction was a proposition for which the misty air was responsible. "I'm going to shut off the juice," announced Billy to his observer. "Keep your ears open, my festive." With the switching off of the ignition the seaplane commenced a long glide. The almost total silence, save for the swish of the air against the planes and struts, was broken by a succession of loud rumbles. Some of the British raiders were at work. "In which direction?" shouted Barcroft. "Ahead on your left, I think," replied Kirkwood. "Seems to me that the smash came from the right," declared the pilot. "Can you see any flashes?" "Not a sign," replied the observer. "The sounds seem as if they are coming from the right now abaft the beam, if anything." "It's a proper mix up," thought Barcroft. "Fog plays the very deuce with sound. If the other fellows are able to drop their bombs it proves that the mist is confined to the upper air. Dash it all! Are we never going to get clear of this muck?" He jerked his goggles upwards until they rested on his cap. For all practical purposes they were useless, although guaranteed to be immune from the effect of moisture. The front of his coat was glistening with particles of ice. Everything he touched was slippery with rime. Jets of vapour, caused by the cold moisture coming in contact with the warm cylinders, drifted into his face and buffeted his bloodshot eyes.