Eventually he found the band of frequencies upon which they communicated, and was perhaps the only human being ever to master their mathematico-symbolic language; but he confided in no one. He could trust no human brain except his own to resist the prying forces of the machines. He drifted from job to position to situation and back to job, because he had very little interest in whatever it was that he was supposed to be doing at the time—his real attention was always fixed upon the affairs of the creatures of metal.

Stone had attained no heights at all in his chosen profession because not even the smallest of his discoveries had been published. In fact, they were not even set down upon paper, but existed only in the abnormally intricate convolutions of his mighty brain. Nevertheless, his name should go down—must go down in history as one of the greatest of Humanity's great.

It was well after midnight when Ferdinand Stone walked unannounced into the private study of Alan Martin, finding the hollow-eyed admiral of the Earth space-fleet still fiercely at work.

"How did you get in here, past my guards?" Martin demanded sharply of his scholarly, gray-haired visitor.

"Your guards have not been harmed; I have merely caused them to fall asleep," the physicist replied calmly, glancing at a complex instrument upon his wrist. "Since my business with you, while highly important, is not of a nature to be divulged to secretaries, I was compelled to adopt this method of approach. You, Admiral Martin, are the most widely known of all the enemies of the automatons. What, if anything, have you done to guard the Fleet against them?"

"Why, nothing, since they have all been destroyed."

"Nonsense! You should know better than that, without being told. They merely want you to think that they have all been destroyed."

"What? How do you know that?" Martin shouted. "Did you kill them? Or do you know who did, and how it was done?"

"I did not," the visitor replied, categorically. "I do know who did—a Russian named Narodny. I also know how—by means of sonic and super-sonic vibrations. I know that many of them were uninjured because I heard them broadcasting their calls for attention after the damage was all done. Before they made any definite arrangements, however, they switched to tight-beam transmission—a thing I have been afraid of for years—and I have not been able to get a trace of them since that time."

"Do you mean to tell me that you understand their language—something that no man has ever been able even to find?" demanded Martin.