Tom took Koku into his service, somewhat to the dismay of Eradicate, who was desperately jealous. But poor Eradicate was getting old, and could not do as much as he thought he could. So, in a great measure, Koku replaced him, and Tom found much use for the giant's strength. Tom had begun his inventive work when, some years before this story opens, he had bargained for Mr. Damon's motorcycle, after that machine had shot its owner into a tree. Mr. Damon was, naturally, perhaps, much disgusted, and sold the affair cheap. Tom repaired it, made some improvements, and, in the first volume of this series, entitled "Tom Swift and His Motor-cycle," you may read of his rather thrilling adventures on his speedy road-steed. From then on Tom had passed a busy life, making many machines and having some thrilling times with them. Just previous to the opening of this story Tom had made a peculiar instrument, described in the volume entitled "Tom Swift and His Photo-Telephone." With that a person talking could not only see the features of the person with whom he was conversing, but, by means of a selenium plate and a sort of camera, a permanent picture could be taken of the person at either end of the wire. By means of this invention Tom had been able to make a picture that had saved a fortune. But Tom did not stop there. With him to invent was as natural and necessary as breathing. He simply could not stop it. And so we find him now about to show to his chum, Ned Newton, his latest patent, an aerial warship, which, however, was not the success Tom had hoped for. But just at present other matters than the warship were in Tom's mind. The red shed was on fire. That mere statement might not mean anything special to the ordinary person, but to Tom, his father, and those who knew about his shops, it meant much. "The red shed!" Tom cried. "We mustn't let that get the best of us! Everybody at work! Father, not you, though. You mustn't excite yourself!" Even in the midst of the alarm Tom thought of his father, for the aged man had a weak heart, and had on one occasion nearly expired, being saved just in time by the arrival of a doctor, whom Tom brought to the scene after a wonderful race through the air. "But, Tom, I can help," objected the aged inventor. "Now, you just take care of yourself, Father!" Tom cried. "There are enough of us to look after this fire, I think." "But, Tom, it--it's the red shed!" gasped Mr. Swift. "I realize that, Dad. But it can't have much of a start yet. Is the alarm ringing, Koku?" "Yes, Master," replied the giant, in correct but stilted English. "I have set the indicator to signal the alarm in every shop on the premises." "That's right." Tom sprang toward the door. "Eradicate!" he called. "Yais, sah! Heah I is!" answered the colored man. "I'll go git mah mule, Boomerang, right away, an' he--"