Lords of the Stratosphere

In five minutes he turned to Jeter with a queer expression on his face. "Well," he said, "what's to do about it? What is it? It seems to be some solid substance approximately a quarter mile square. But it can't be true! A solid substance just hanging in the air at ninety thousand feet! It's beyond all imagining!" "What man can imagine, man can do," replied Jeter...