Just then there was a blinding flash of light a little way ahead of them, accompanied by such a terrific crash of thunder that their ears rang.
"Gee!" cried Bob, "that was a close call! I'll bet that bolt came within a rod of striking us."
"A miss is as good as a mile," shouted John cheerfully. He and the others found that they would have to yell in order to be heard, so great was the noise from engine and storm.
Zip! went a zigzagging livid streak across their range of vision. It seemed to be running straight for them, and instinctively they dodged—all but Tom and John. These old veterans continued to gaze coolly straight ahead as though nothing had happened. Crash-h! went a clap of thunder. It seemed as if the whole heavens were being turned topsy-turvy. Even the airplane, usually so steady, heaved and rode like a rocking-horse.
The two younger members of the party were not to be blamed for feeling pretty well frightened by this time. It was one thing to be cutting through the fleecy white clouds of a calm day, and quite another to go stabbing through murky black ones which were rolling angrily, ejecting both wind and rain, and spitting out vicious roars and jagged streaks of pale-blue flame. One moment they would be in gloom; the next instant a cloud would be rent asunder with a ripping, tearing sound, and the whole turbid, boiling sky-universe would be bathed in the ghostly light. What a weird, fantastic, chaotic world they were in!
But it was only for a few minutes that they were in the worst danger. Soon, to their infinite relief, they had reached their "ceiling." They were now 15,000 feet up—almost three miles,—and below them lay the vast sea of troubled cloudland, dark and forbidding, rolling tumultuously like an ocean of curdled ink. It was a novel experience to be running in the clear air over all of this infernality of sounds and sights, while above them the blue, star-studded heavens looked down upon them calmly and peaceably.
For almost an hour the furious storm continued in the lower regions. Then it began slowly to subside. First the lightning stopped, then the thunder. The banks of clouds took on a lighter hue, and began to drift apart; a pinnacle here and a crag there were swept off by the winds, until the masses of nimbus became flattened out into patches of sun-flecked foam as beautiful as fresh-fallen snow.
The anemometer spun slower and slower as the gale decreased in violence, and presently the airplane was gliding along with its normal smoothness. Here and there, between the patches of white cloud, they caught glimpses of the ultramarine sea, thousands of feet below them.
It was so cold up here, even with the windows closed, that all the boys were shivering in their warmest wraps. The air, too, was so rarefied that it was with considerable difficulty that they could breathe, for they had been in it for some time. Not one flyer in a hundred can live at an altitude of twenty thousand feet, as he bleeds at the nose and mouth; and our aviators were up to within five thousand feet of that height. It was now time to descend.
John shut off both engines, and they began to volplane down in a great stillness, sailing like an immense hawk. Lower and lower they went—fourteen, thirteen, twelve, eleven, ten thousand feet. Now they were gliding through clear, thin air; now cutting a hole through a heavy cloud so impregnated with moisture that it sweat over the glass and the boys would have to wipe a sleeve across hastily to improve the vision. Eight, seven, six, five, four, three, two!