Page:Popular Science Monthly Volume 71.djvu/188

182 This fissuring may have been the result of shrinkage by cooling or it may have been due to a sinking of the lava in the cone. It seems probable that the secondary cone was formed as follows: Previous to the eruption of 1869, the pressure from below fissured the main cone. Through this fissure the lava welled up, flowing away as a lava stream. The stiffer and cooler lava, which was later forced up, failed to flow, and hardened to form the mound.

The Main Cone.—The ascent of the main cone is difficult because of the insecure footing afforded by the rolling ash and cinders and the steepness of the lava wherever it outcrops, as well as because of the altitude. The slope of the cone is between 35 and 39 degrees, although from a distance it appears to be much greater.

The Crater.—The rim of the crater is entire with the exception of a depression through which a lava stream flowed in 1885 and again in 19(13. The view into the crater from The higher portions of its rim is very impressive, even awe-inspiring. The slope on the outside of the rim is that of the volcano, but the inside drops precipitously to the bottom of the crater, a depth of more than 100 feet in many places. On account of the great quantities of steam which arc continually rising.

it is only when an occasional gust of wind partially lifts the steam that one can get a glimpse of the floor of the crater. Descent into the crater by way of the breach in the side is comparatively easy and is attended with less danger than the view from the rim prophesied. The floor is covered with scoriaceous lava equaling, if not exceeding, in ruggedness that of the lava flow at the foot of the volcano. Steam with a