In such a wild and primitive setting, human civilization seemed a distant, unimportant issue. The menace of the desert, of naked nature, alone seemed real. No wild tale was incredible there. And the wonderful girl before me, smiling, cool and resourceful, seemed to fit in with that rough scenery, seemed almost a part of it. Ellen was the kind of woman who can master her environment. "Coming down here was a pretty severe change for a campus queen, wasn't it?" I asked her. "The royal blood never flowed too freely in my veins," she said. "I rather like it here. The ore train from Durango brings the mail twice a week, and I read a lot. Then, I'm beginning to love the desert and the mountains. Sometimes I feel almost like worshipping old Mocolynatal. They say the Indians did." "I wonder if it's ever been climbed?" "I think not. Unless by the owners of the red airplanes. Dad thinks they are things that have come down out of the upper air to attack the earth. I've always been sorry I wasn't here when the tiger was killed, but this promises a bigger adventure yet! And I'll be right in the middle of it!" She laughed. The Death Ray "I hadn't heard of the tiger's misfortune," I said, a little amused at her eagerness for adventure. "You know Uncle Jake had a ranch down on the Nazas. Once he trailed a tiger up here with his hounds. He killed him right here, and happened to see the glitter of gold in the blood-stained quartz. He named the mine El Tigre--The Tiger. Along with the gold ore are deposits of _monazite_--thorium ore. Dad began to work them when we came to get thorium to use in his experiments." "Say, Bob," the Doctor called, "I want to sh-sh-sh-show you something. Come on in the lab." The little man took my arm and hurried me down the long cool hall, and up a flight of steps to a great room on the second floor. It suggested an astronomical observatory; it was circular, and the roof was a great glass dome. In the center and projecting through the dome was a huge device that resembled a telescope. About the walls a variety of scientific equipment. "That's my r-r-r-ray machine," he said. "Modified adaptation of the old Coolidge tube, with an electrode of molten _Vernonite_. _Vernonite_ is my invention--an alloy of thorium with some of the alkaline earth metals. When the alloy is melted there is a comparatively rapid atomic disintegration of the radioactive thorium, and the radiation is modified by passages through a powerful magnetic field, and by polarization with quartz prisms. The Vernon Ray has characteristics controllable by the adjustment of the apparatus, generally resembling those of the ultra-violet or actinic rays of sunlight, but intensified to an extreme degree. "The chemical effects are marvelous. The Vernon Ray will bleach indigo, or the green of plant leaves. It stimulates oxidation, and has a tendency to break up the proteins and other complex molecules.