The Metal Horde By John W. Campbell, Jr. _Author of "When the Atoms Failed."_ Illustrated by DE PAUW _What with calculating machines and robots and now perhaps even mechanical airplane pilots, there seems no limit to the possibilities in the realm of working machinery. We have seismographs that can locate the place of distant earthquakes, and machines that can solve, in a comparatively short period, problems in the higher calculus that would otherwise take brilliant mathematicians an endless time to do. It seems to us quite logical that machines might some day, perhaps in the distant future, be developed to solve for our scientists now apparently insoluble problems. Or they might even be made to state their own problems and work them out--in other words, it might some day be possible to have a machine with almost a working brain. According to our author, this will be possible and his final explanation of his idea is exceedingly clever and novel. There is no question Mr. Campbell knows his science and he has by this time proved his ability to weave a great deal of sound science into an absorbing scientific fiction story of exceeding plausibility._ [Transcriber's Note: This etext was produced from Amazing Stories April 1930. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] It would seem lack of generalship that permitted them to be discovered so soon, for had we not picked up those signals from the ether we should not have received that warning that meant so much to us, and it might well have been that this system would have acquired a new population. For it would have needed but little to shift the balance the other way! Once I watched Steven Waterson save the civilization of the Earth, but now I saw him in a greater rôle, for it was he who made possible the defeat of the Sirians. But even had his brilliant mind succeeded in working out the problem of the de-activating field without the precious hours gained by that warning, many millions more would have died before they could have escaped from Mars. I was in his laboratory at the time he received the messages from the System government telling the import of those strange tone-signals out there in space. I seem fated to be with that man every time some great event breaks on the System. I was with him when Dr. Downey announced his discovery of the secret of old age--or, better, its prevention. Waterson was forty-two now, in years, but in body he was still twenty-eight for it was late in 1947 that he had taken Dr. Downey's treatment. Those strange tone-signals had been heard faintly for days, but it was not until July 8th, 1961, that they were located in space, and then man began to realize something of the message they might bear.