Far above the earth Jack and Tom could look down upon a patchwork of villages, farms, green pastures, yellow grain fields and stretches of woodland. They were too far up to distinguish figures, but they could see the white steam of rushing trains along the railroad tracks, and even catch the sound of the engines' whistles.
Beyond glinted the blue of the sea flecked with sails and with here and there a steamer's smoke smudging the horizon. Both lads were in high spirits. It seemed good to be navigating the air again. Every now and then inquisitive, high-flying crows would swoop toward the machine and then dash off again with alarmed squawks.
Although they were making a high rate of speed, they hardly seemed to be moving as they soared in long circles. To get a sense of rapid motion, stationary objects must be in sight. In the lonely air it was hard to tell that they were moving at all except by looking down at the earth which, as they rose, appeared to be rushing from them, as if it were sinking through space.
But novel as all these sensations would be to an aërial novice, they were an old story to the boys. Jack devoted his attention to testing a new steering appliance he had equipped the craft with, and Tom watched his engines with an eagle eye to detect a skip or a "knock."
"How high now?" asked the young engineer after an interval.
Jack glanced at the barograph on the dashboard in front of him.
"Three thousand feet," he said.
"Might as well connect the alternator?" said Tom interrogatively.
Jack nodded, and Tom threw a lever which brought the generator of high frequency currents in contact with the motor by means of a friction fly-wheel. The alternator began to buzz and spark, crackling viciously.
A sort of metal helmet with two receivers attached to it, one on each side, lay handy at Jack's hand. In front of him was the transmitter joined to the metal box which contained the microphone, transformers and inductance tuning coil. Tuning in the aërial apparatus was effected by means of a small knob projecting through a slit in the metal box enclosing the delicate instruments including the detector. By working this knob the tuning block was moved up and down the coil till a proper "pitch" was obtained.