Emil Crawford's condition was more serious. Not only was the old man's frail strength nearly exhausted, but he was also badly wounded. His thin chest was seared by two great livid areas of burned flesh, the nature of which puzzled Dixon as he began to dress the injuries. They seemed of radioactive origin, yet in many ways they were unlike any radium burns that Dixon had ever seen.
While Dixon was working over him, Crawford stirred weakly and opened his eyes. He sighed in relief as he recognized his surroundings.
"Good boy, Bruce!" he commended wanly. "We are safe here among the insulating veins of lead ore in the mountain. This is where Ruth and I were trying to come after we escaped from those devils to-night. But, Bruce, how did you guess the radioactive nature of the Green Sickness in time to avoid falling a victim to it as soon as you left the shelter of your laboratory?"
"My escape was entirely luck," Dixon admitted grimly. "To-night I left my laboratory for the first time in three days. I found a world gone mad, with a strange green moon blazing down upon a land of living dead men, and with marauding monsters hideous enough to have been spawned in the Pit itself. What in Heaven's name does it all mean?"
am afraid that it means the end of the world, Bruce," Crawford answered quietly. "It was a little over forty-eight hours ago that the incredible event first happened. Without a moment's warning, the moon turned green! Hardly had the world's astronomers had time to speculate upon this amazing phenomenon before the Green Sickness struck—a pestilence of appalling deadliness that swept resistlessly in the path of those weird green rays. Wherever the green moon shone, every living creature succumbed with ghastly swiftness to the condition of living death that you have seen.
"Westward with the racing moon sped the Green Sickness, and nothing stayed its attack. The green rays pierced through buildings of wood, stone, and iron as though they did not exist. A doomed world had neither time nor opportunity to guess that lead was the one armor against those dread rays. To-night, Bruce, we are in all probability the only three human beings on this planet who are not slumbering in the paralytic stupor of the Green Sickness.
"Ruth and I were stricken with the rest of the world," Crawford continued. "We recovered consciousness hours later to find ourselves captives in the Earth-camp of the invaders themselves. You probably saw the display of lights that marks their camp down in the valley a mile beyond my place. We have learned since that the space ship of the invaders dropped silently down into the valley the night before the moon turned green and established the camp as a sort of outpost and observatory. They left two of their number there as pioneers, then the rest of them departed in the space ship for their present post up near the moon.
"Ruth and I were revived only that the two invaders in the camp might question us regarding life on this planet. They have a science that is based upon principles as utterly strange and incomprehensible to us as ours probably is to them. They probed my brain with a thought machine. It was an apparatus that worked both ways. What knowledge they got from me I do not know, but I do know that they unwittingly told me much in the bizarre and incredible mental pictures that the machine carried from their brains to mine.