She led the way through the narrow passage into the valley. A deep gorge, it was, with the black sheer cliffs on either side pressing close. Ten feet forward, I stopped short, staring in amazement. Advancing toward me like a column of infantry came a long line of Larynx miners. They walked slowly, looking straight ahead, moving down the center of the gorge toward the entrance. But there was more! A kite car was drawn up to the side. The windscreen had been removed, and mounted on the hood was a large bullet-like contrivance that looked not unlike a search lamp. A blinding shaft of bluish radiance spewed from its open end. Playing it back and forth upon the marching men were Jimmy Baker and Xartal, the Martian. "Ultra violet," Grannie Annie explained. "The opposite end of the vibratory scale and the only thing that will combat the infra-red rays that cause red spot fever. Those men won't stop walking until they've reached Shaft Four." Grannie Annie told her story during the long ride back to Shaft Four. We drove slowly, keeping the line of marching Larynx miners always ahead of us. Jimmy Baker had struck a new big lode of Acoustix, a lode which if worked successfully would see _Larynx Incorporated_ become a far more powerful exporting concern than _Interstellar Voice_. Antlers Park didn't want that. It was he or his agents who placed those lens buttons in the Larynx barracks. _For he knew that just as Jupiter's great spot was responsible for a climate and atmosphere suitable for an Earthman on this Eighth Moon, so also was that spot a deadly power in itself, capable when its rays were concentrated of causing a fatal sickness._ Then suddenly becoming fearful of Grannie's prying, Antlers Park strove to head her off before she reached Shaft Four. He did head her off and managed to lure her and Baker and Xartal into the Shaft barracks where they would be exposed to the rays from the lens button. But Grannie only pretended to contract the plague. Park then attempted to outwit Ezra Karn and me by returning in Jimmy Baker's kite car with a cockatoo image of Grannie. * * * * * I listened to all this in silence. "But," I said when she had finished, "how did Park manage to have that image created and why did the mine laborers walk out into the Baldric when they contracted the fever?" Grannie Annie frowned. "I'm not sure I can answer the first of those questions," she replied. "You must remember Antlers Park has been on this moon five years and during that time he must have acquainted himself with many of its secrets. Probably he learned long ago just what to do to make a cockatoo create a mental image.