There was a rosy hue about the little mountain, and after a brief rest they headed for the spot. "There's nothing here!" exclaimed Jack in disgust, as he and Mark, in a final spurt, reached the base of it. "Nothing but ordinary dirt." Mark looked down. He dug his heel into the sod. Then he uttered a cry of triumph. "Here it is! Here it is!" he cried. "It's under the grass! We've got to dig it up!" He knelt down, and began to tear away the sod with his hands. Jack did the same, and when they had lifted aside the tangle of roots and grass, they saw beneath it a dull gleaming red substance, like clay. "That's it! That's it!" shouted Mr. Roumann. "We've found it!" He stooped over, and with his knife began digging some up. "It's neither warm, nor does it give any light," said Mr. Henderson in disappointed tones. "No; it requires special electrical treatment," replied Mr. Roumann. "I know how to do it, though. Now we shall all be millionaires! There is enough here to make us wealthy for life!" He began filling his iron boxes, the rest helping him. They were engaged in getting out the Cardite, all working with feverish haste, when Jack, looking up, saw a Martian officer regarding the actions of the world-dwellers with his great, bulging eyes. CHAPTER XXVIII THE ATTACK "They've discovered us!" exclaimed Jack, as he stood up and watched the Martian. "What?" cried Mr. Roumann. "Oh, it's only one of them," he added, "and he hasn't any of those electrical sticks. Go ahead and take some more of the Cardite." But the Martian advanced on the travelers, and, by his voice and gestures, seemed to be warning them to stop taking the red material. "Maybe he's a guard," suggested Mark. "Very likely," assented Professor Henderson. "I'll see if I can't scare him with my gun," remarked Andy. "I've put in more powder, and a heavier bullet." He fired in the air, over the Martian's head, but to the surprise of the adventurers the weapon only gave a faint sound, like that of a pop gun, while the bullet rolled from the barrel and dropped at Andy's feet. "Why, that's worse than ever!" he exclaimed. "I guess the red stuff must have taken all the power out of your gun, Andy," said Mark. The Martian stood still for a moment. Then he spoke again, more earnestly than before, and waved the strangers away from the red hill. "We're not going," said Mr. Roumann, and he added a few of the Martian words he had learned, endeavoring to state that they were going to take only a little of the Cardite. The officer, with a last warning shake of his big head, suddenly turned and ran away. "I guess he's gone for reinforcements," said Jack. "No matter," spoke Mr. Roumann. "We'll soon have all we can carry, and then we'll hurry back to the projectile. When we get there we can defy them."