"The mysterious red substance!" murmured Mr. Roumann. "It is a source of power, it gives forth light, and what will it not do? I must certainly secure some of it!" The red glow increased as it grew darker outside, and, looking through the glass sides of the palace, the boys saw that the palace was surrounded by a great crowd of Martians, who were watching what went on within. CHAPTER XXIV A MARVELOUS SUBSTANCE "Say, that's a good way to have a building," observed Jack in a low voice to his chum. "Those who can't get in can see just as well what's going on as if they were here. But I wonder what he's saying?" "Probably telling his people about us," replied Mark, and this seemed to be so, for Silex Corundum, as they later learned was the name of the ruler of Mars, frequently motioned toward the adventurers, who stood in a group in front of the platform. Much interest was manifested by the throng, and even those on the platform, who seemed to be members of a sort of council or governing body, could not restrain their interest. When the chief ruler had ceased speaking the Martian with the triangle on his head--the one who had first greeted the world travelers, stepped forward, and made an address. "He's telling 'em how we got here," was Mark's opinion, and Jack nodded. When this one had finished, the guide who had conducted them to the palace had his turn, and at greater length he described the strangers, the curious craft in which they had arrived on the planet, and many other details, which, of course, our friends could not comprehend. This done, Silex Corundum made another address, and at its close a great blackboard was brought forward, some pieces of chalk were handed to Mr. Roumann and to Professor Henderson, and by signs they were invited to illustrate something of themselves and their wonderful journey. "What shall we draw?" asked Mr. Henderson. "First see if you can make them understand something of the earth where we came from," suggested Mr. Roumann; and the professor, who was a good draughtsman, soon placed on the board a sort of map of the universe, indicating the position of Mars, the sun, the other planets and the earth. To his surprise a delighted shout told him that he was understood. The chief ruler, with a rapid motion, pointed to a great telescope, located in one corner of the big audience chamber. He motioned for the travelers to look through it, and after it was adjusted he pointed to the drawing of the earth on the board, and indicated that the adventurers could see their own planet through the telescope. Mr. Roumann looked first. Then he uttered an exclamation. "Can you really see our earth?" asked Jack. "I can! Look for yourself! This is a marvelous telescope! No wonder the Martians understand something about us. They can clearly make out the shapes of our continents."