The bacteriologist heard a steady, humming drone, like a swarm of angry bees--felt a peculiar, soothing warmth about his head; and then he slept. Only a moment or two seemed to have passed when he awoke. The strange device on his head was removed and put away; and then, to Parkinson's amazement, one of the three men, evidently the leader, spoke--in English! "Now that you have recovered consciousness," he remarked in a cold, expressionless voice, "you had better realize at the very beginning that you are completely in our power. Any effort to escape will be futile, for there is only one way to reach the outside; the opening through the top; and only one means of travel through that opening: the sphere. And since you know nothing about the operation of the machine, any attempt to run it would be disastrous to you. "If you promise to refrain from violence, we'll release you, and give you some measure of freedom. We'll do this because you can be of assistance to us in one of our tasks here on your planet." Parkinson assented readily; he knew he could gain nothing by rejecting their offer. "Of course I'll promise. But--but, how did you learn English?" he asked in bewilderment. "You taught us," the leader replied. "That device we placed upon your head created a duplicate of your knowledge in our minds. We knew your language, your world, indeed, yourself, as well as you do." Parkinson shook his head in amazement. Another question came to his mind as the men released him. He was interrupted before he could give it expression. * * * * * "Don't ask," the leader exclaimed. "I'll tell our entire story so that you'll have no occasion to annoy us with your questions. "We're Venerians," he began, "inhabitants of the planet you call Venus. For ages our world has been overcrowded. A short time ago, the conditions became so acute that something had to be done. It was suggested that we seek another habitable planet to which our people could migrate. "Your Earth was thought to be the world with physical conditions most closely resembling those of Acor, or Venus. Our scientists set to work immediately, using forces and devices with which you are totally unfamiliar, and constructed several missiles which they hurled at Earth. These missiles, spherical masses closely resembling meteors, were set to explode after a certain period of contact with an atmosphere similar to our own. By their explosion we on Venus could determine whether or not this world had a breathable atmosphere. "Upon our deciding that the Earth was habitable, we built this great machine. It is chiefly composed of our greatest heat-resister, a metal we call thoque; I see no corresponding word in your vocabulary; evidently you are unfamiliar with the element, or else it is unknown on Earth.