To add to the loneliness of the night, he now swept into a stratum of fog. It hung in an enveloping mass about the ship, creeping into the cockpit, clouding the instruments. As Hal rode high to avoid the fog, he swept into an area of black clouds, snow clouds. At this altitude, he found the air filled with hail. In a moment these heavy, dangerous ice pellets were rattling angrily against the plane. Like a hunted creature, Hal shot this way and that striving to dodge the zone of ice and sleet. It was no use; the ice pall pursued him, sheeted his ship. Wing surfaces were flung out of balance with additional weight, controls began to clog. There was nothing to do for it save drop back down into the warm, foggy layers of air just above the waves. As soon as he hit the warm zone, ice began to melt, its heavy, retarding weight slid off. The speed of the ship, which had lagged below eighty miles the hour, now began to zoom back up well over the hundred mark.