"What is it?" inquired Jack. "Look, the needle went all the way around that time." Mr. Roumann bent over the gauge. Then he consulted some charts of the sky, and made a few calculations. "Boys, I am afraid we're approaching a large comet," he said gravely. "And, what is worse, it is attracting us toward itself. We are in great danger!" CHAPTER XIX ESCAPING A COMET The two boys looked at the German scientist. He was gazing, as if fascinated, at the swiftly moving needle of the gage that had told of the nearness of the comet. "How far from it are we?" asked Jack. "Many thousands of miles," replied Mr. Roumann. "But that distance is nothing compared to the rate at which we are traveling. We are almost certain to crash into it, or the comet will collide with us." "And when it does, what will happen?" inquired Mark quietly. "That is hard to say," was the answer of the German. "We know very little about the composition of comets. They may be composed merely of flaming gasses, or they may be a train of burning meteors, held together by attraction. The head may be some vast, blazing world, as large as our planet. In fact, comets are very baffling to astronomers." "Well, if a comet is nothing but gas, it won't hurt if we run into it, will it?" inquired Jack. "That's just the trouble. We don't know that it is gas," said Mr. Roumann. "It may be solid, and then to rush into it at terrific speed would mean that we would be demolished. Also, if the gas is flaming, you can easily imagine what would happen to the Annihilator. There would be nothing left of it--or us--in less than an instant." "But isn't there some way of escaping it?" asked Mark. "I'm going to try," responded Mr. Roumann. "Jack, ask Professor Henderson to step here. I wish to consult him." Jack delivered the message, and it was overheard by Washington White. Something in Jack's manner told the colored man that there was trouble aboard. "What's de mattah?" he asked. Jack saw no reason for concealing the danger from the cook. "We're heading into a comet," he, said. "What? One ob dem tings wid long, fiery tails, Massa Jack?" The youth nodded. "Am we gwine t' hit it?" "I'm afraid so." "Well, I hopes we does!" exclaimed Washington with great earnestness. "I hopes we knocks it clean outen de universe, dat's what I hopes." "We're a great deal more likely to be knocked out ourselves, Wash."