It did not take Derek long to accustom himself to the peculiarities of the sea-plane. Had it been one of the flying-boats that the Lieutenant had been called upon to pilot across the seas the task would have been an awkward and difficult one. Once fairly up, there is very little difference between an aeroplane and a sea-plane, but there are wide distinctions between the latter and the huge flying-boats which, devoid of floats, rely upon their hulls for buoyancy when on the water.

Derek elected to fly fairly high, maintaining a height of five thousand feet. This gave him a chance, in the event of making a blunder with the unaccustomed system of controls, while at the same time there was less chance of coming across an air-pocket.

Quickly he discovered that his hand had not lost its cunning. Although it was months—it seemed like years—since Derek had had control of joy-stick and rudder-bar, the old skill still remained. And the exhilaration of it! To be once more rushing through space, soaring high above the waves!

"This is some stunt," thought the reinstated pilot. "Wonder what\'s taking the old Brass Hat to Spain? Joy-ride, or what? After all, it\'s all in a day\'s work."

Applying the automatic steering device Derek turned to consult the charts. A hasty examination showed that his predecessor had faithfully recorded the course almost up to the time of the triplane\'s involuntary descent. The red-inked line and rough-pencilled notations were of considerable service. They enabled Derek to set a compass-course corrected for air leeway and ordinary magnetic deviation. Provided the force and direction of the wind remained fairly constant, the task of piloting the seaplane would be a fairly simple matter.

It was aviation de luxe. The pilot\'s house, with windows of triplex glass affording an all-round view, was warm and free from buffeting draughts. With the glass in position the roar of the powerful engines was reduced to a barely perceptible purr.

Thirty miles to the nor\'ard the rugged uplands of Dartmoor could be clearly discerned, while ahead, and slightly on the starboard bow, could be seen the indented outlines of the Cornish coast, for Derek was purposely keeping within easy distance of shore until well over the Scillies. Then it was his intention to strike a bee-line for his destination. Occasionally altering the automatic course-director, Derek found that he had plenty of time at his disposal. After a while things became tedious. Cooped up in a glass box he missed the actual sensation of flying through the air. It was more like sitting in a carriage of an express train than being absolutely in control of an air-craft. Compared with the lift and heave of the ocean the motion seemed a very tame affair.

"By Jove! the Pater was right after all," soliloquized Derek. "Flying\'s all very well; but it\'s the sea that scores—scores every time. There\'s nothing to equal a life afloat."

He let down one of the sliding glass panels. The rush of air acted like a tonic. The suggestion of actual aerial speed reasserted itself. There was something indescribably joyous in the sensation. He could almost imagine himself back in his old \'bus circling over the Hun lines.

He missed the airman\'s flying-helmet, goggles, and leather coat. It was bitterly cold. The wind buffeted his face until his eyes smarted and his ears throbbed and tingled, yet it was better, in his opinion, than being cooped up in a glass box.

Just then the door opened and one of the crew entered. Vainly the man tried to make himself understood, and it was not until the glass slide had been replaced that Derek was able to engage in conversation.

"The actuating wire of the starboard aileron of the lower plane\'s carried away, sir," reported the man in quite a matter-of-fact tone. A housewife on discovering that a cat had stolen the morning\'s milk would have shown much more concern. "I\'ll just nip along and make a temporary repair."

"Very good!" replied Derek, cutting out the automatic control, and grasping the joy-stick. "Carry on!"

The airman withdrew. Presently Derek saw him cautiously making his way along outside the covered fuselage; then, throwing himself flat upon the plane and grasping the forward edge, the man began to work his way outwards. Only his hold upon the sharp edge of the cambered wing prevented him being swept away like a piece of paper by the two-hundred-mile-per-hour wind.

Hanging on like a limpet, and keeping his head well down, the dauntless airman at length reached the spot where the wire had parted—a distance of about six feet from the extremity of the plane. In spite of the man\'s weight the triplane evinced no tendency to tilt, although it required a slight alteration of helm of the horizontal rudder to counteract the additional resistance set up by his body. In this hazardous position, holding on with one hand, and keeping his legs planted firmly against a vertical strut, the airman set to work to make good the damage.

First the ends of the severed wire had to be secured in a bowline made in each. Through these loops the clips of a bottle-screw were placed, and the wires drawn up to their original tension.

Working at a height of five thousand feet, while travelling at a speed of one hundred and sixty miles an hour—for Derek had ordered the motors to be throttled slightly—the gallant airman completed his task in twenty minutes; then, benumbed with the cold and with lying in a decidedly awkward position, he made his way back to the shelter of the enclosed fuselage.

By this time the Scillies, looking like a scattered heap of pebbles showing above a large sheet of tranquil water, were left astern. Ahead great masses of indigo-coloured clouds, tinged with vivid coppery hues, betokened the presence of a storm-centre. Ragged wisps of dark-grey vapour were scurrying over the sky, interrupting at frequent intervals the hitherto continuous blaze of sunlight.

Derek realized that there was no escape except by a tremendously long detour. Since time was a decided object, such a course was impracticable, for there would be the risk of being carried away a long distance from the objective. It was a case of carrying on at full speed, and taking one\'s chance with the approaching storm.

"What do you make of that?" enquired a voice, as Derek again closed the window of the pilot\'s house.

Turning, the Lieutenant found the exalted passenger—the Brigadier-General—standing behind him.

"Atmospheric disturbance of some magnitude, sir," replied Daventry. "There is no cause for anxiety," he added.

"Isn\'t there? by Jove!" ejaculated the Brigadier-General grimly. "Hope you\'re right, young man. What\'s up with your meteorological experts at the Air Ministry, I should like to know? Their forecast is \'light variable breezes; conditions fit for cross-country flights with all types of machines\'. Someone adrift somewhere, I should imagine."

In his mind Derek was obliged to admit the impeachment.

"But that refers to the British Isles, sir," he remarked diplomatically. "Already we are approaching the Bay of Biscay."

"Let\'s hope we don\'t have to swim for it," growled the Brigadier-General. "I\'m trusting to you. I\'ll stay here, if you don\'t mind."

"You\'d do better in your cabin, sir," Derek reminded him. "We may be in for a bit of a dusting, and you\'ll be all right lying on your bunk."

"Lying on my bunk!" exclaimed the Staff Officer loudly. "By Gad, sir! I\'ve never yet faced danger lying down. J\'y suis; j\'y reste is my motto."

Before Derek could say anything further the triplane entered the storm-zone. The first blast of disturbed air tilted the gian............