We passed the famous and only Mud Geyser an hour before daybreak. Things were in a bad way with him, judging from the noise. The mutterings of the old mud-slinger in his quieter moments reminds me very much of a Chilkat Mission Indian reciting the Lord's Prayer in his native tongue--just a rapid succession of deep gutturals. But when some particularly indigestible concoction--served, possibly by subterranean dumb-waiter from the adjacent Devil's Kitchen--interferes with the gastronomies of the old epicure, his voice is anything but prayerful. Carr said it reminded him of something between a mad bull buffalo and a boat load of seasick tourists when the summer wind stirs up the Lake. But Carr was too tired and disgusted to be elegant. Indeed, we were both pretty well played out. Personally, I felt just about like the Mud Geyser sounded. After about an hour's groping in the dark, we found an emergency cabin near the Mud Geyser. Building a fire, we warmed and ate a can of salmon. When it was light enough to see, we slipped on the ski and came through on the crust in short order. Thumb Emergency Cabin, April 15. Making a start before daybreak, we crossed Yellowstone Lake on the ice. It was a wonderful opportunity to watch the light and shade effects on the encircling mountains. Far to the south-west there is a very striking pyramidal peak. Two flat snow-paved slopes of the mighty pile, divided by an even ridge of black rock that rears itself in sharp contrast to the beds of white that bulwark the base, form the sides of the pyramid. The southeastern side so lies that it catches the first rays of the morning sun and sends them off in shimmering streamers across the lake--Nature's heliographic signal of the coming day. An hour or more later the sun itself appears above the eastern hills, silvering the tops of the frosted fir trees and whitening the vaporous clouds above Steamboat Point and Brimstone Basin. The green ice in the little glaciers near the summit of the big mountain kindle and sparkle like handfuls of emeralds, and the reflected sun-flashes play in quivering motes of dancing light on the snowy flanks of Elephant Back. Meanwhile the south-west face of the great pyramid, lying in heavy shadow, sleeps dull and black until the morning is well advanced. Then, suddenly, without a perceptible premonitory fading of the shadow plane, the whole snow-field becomes a shining sheet, as white and clear-cut as thought carved from alabaster. At noon the sun, standing full above the black dividing line of rock, sheds an impartial light on either side of the mountain. Perspective is lost for the moment, and there appears to be but one broad field of snow, with a black line traced down its middle.