Colston was standing by the open door of the wheel-house as Arnold communicated his order to the engine-room by pressing an electric button, one of four in a little square of mahogany in front of the wheel. There was no vibration or grinding, as would have been the case in starting a steamer, but only a soft whirring, humming sound, that rose several degrees in pitch as the engines gained speed, and the fan-wheels revolved faster and faster until they sang in the air, and the _Ariel_ rose without a jar or a tremor from the ground, slowly at first, and then more and more swiftly, until Colston saw the ground sinking rapidly beneath him, and the island growing smaller and smaller, until it looked like a little patch on the dark grey water of the sea. Away to the north and west he could see the innumerable islands of the Hebrides, while to the east the huge mountainous mass of the mainland of Scotland loomed dark upon the horizon. When the barometer marked eight hundred feet above the sea-level, the _Ariel_ passed through a stratum of light clouds, and on the upper side of this the sun was still shining, shooting his almost level rays across it as though over some illimitable sea of white fleecy billows, whose crests were tipped with rosy, golden light. Above the surface of this fairy sea rose north-eastward the black mass of Ben More on the Island of Mull, and to the southward, the lesser peaks of Jura and Islay. While he was still wrapped in admiration of the strange beauty of this, to him, marvellous scene, the _Ariel_ had risen to a thousand feet, still almost in a vertical line from the island. Arnold now pressed another button, and the stern propeller began to revolve swiftly and noiselessly, and Colston saw the waves of the cloud-sea begin to slip behind, although so smooth was the working of the machinery, and the motion of the air-ship, that, but for this, he could hardly have guessed that he was in motion. Arnold now turned a few spokes of the wheel, and headed the _Ariel_ due east by the compass. Then he touched a third button. The side propellers began to turn swiftly on their axes, and, at the same time the speed of the fan-wheels slackened, and gradually stopped. Colston now began to feel the air rushing by him in a stream so rapid and strong, that he had to take hold of the side of the wheel-house doorway to steady himself. "I think you had better come inside and shut the door," said Arnold. "We are getting up speed now, and in a few minutes you won't be able to hold yourself there. You'll be able to see just as well inside." Colston did as he was bidden, and as soon as he was safely inside Arnold pulled a lever beside the wheel, and slightly inclined the planes from forward aft. At the same time the fan-wheels began to slide down the masts until they rested upon the deck. "Now, you shall see her fly," said Arnold, taking a speaking-tube from the wall and whistling thrice into it.