In all directions the ground of Norris Geyser Basin is cracking and changing. The geysers are utterly unreliable, here today and mere hot springs or empty cracks tomorrow. Old Faithful intervals range from thirty-eight to eighty-one minutes, quite irregular. The New Crater was a squirting, scalding jet which killed the trees and vegetation all about. Its seemingly regular, twenty-five foot jets shot up at forty-five degrees inclination about every three minutes. Later, in 1922, I was to find this geyser totally different. Careful studies have shown that water of this elevation boils at 199° Fahrenheit; one geyser gave off 253° Fahrenheit, or fifty-four degrees of superheat, seventy-two feet down its shaft. This is the only place of superheated waters known on earth. The roaring steam of the Black Growler has eighty-one degrees of superheat. The quantity of carbon, sulfur, and chlorine in the waters is so excessive, though it is very small in the rock, that a source of heat from volcanic gas is certain. The net result is thousands of boiling springs of rainwater, soaking a sponge of rhyolite rock over hundreds of square miles, erupting over a remnant volcanic furnace beneath, and eroding and dissolving out basins at the headwaters of the Mississippi. Here is an object lesson in volcanic erosion. Here is a perpetual eruption of volcanic gases which has dwindled after millions of years of melting siliceous and carbonaceous rocks. It recrystallizes them as andesites, rhyolites, and obsidians, and mixes deep steam with rainwater to do the work of erosion and water solution and of deposits, over a vent at the heart of the Rocky Mountains. As usual, this vent has cluttered itself from age to age with the melt of the deep earth crust, namely basalt, which Yellowstone’s lavas show repeatedly from bottom to top of its accumulations. And as usual, the vents themselves are hard to recognize, buried as they are under heapings. In 1897 I returned to the Yellowstone, where I visited Death Gulch, a dismal solfataric gully with a trickle of cold, acid water near Cache Creek. Accompanied by Dr. F. P. King, I climbed up this gorge, where there was a bad smell and burning oppression of the lungs from hydrogen sulfide. It was a V-shaped trench 50 feet deep in volcanic puddingstones, whitened with alum and epsom salts. Bubbles rose through the water in many places. The remains of eight big bears were found in the gorge, clustered in one place. The latest victim was a young grizzly with a clot of blood staining his nostrils from his last hemorrhage. Poison gas had killed him. Earlier visitors had found squirrels, hares, and butterflies and other insects killed by gas. Probably both sulfuretted hydrogen and carbonic acid gas do murder in still weather. However, we had the wind blowing up the gulch. We lit matches in hollows and carbon dioxide did not extinguish them. The same thing had happened when Mr. Weed in 1888 tested for carbon dioxide at Death Gulch.