The cone of Cotopaxi is the smoothest and most symmetrical in the world; perhaps because its eruptions are almost entirely of ashes or fragmentary lava. As no villages lie in its immediate neighborhood, the clouds of ashes have not done so much damage as might be expected.

The first sign of an eruption is the melting of the snow upon the cone. Torrents of water sweep down the mountain. Such an outbreak occurring in 1741, after two centuries repose, the amount of snow accumulated may be imagined. The rush of the water tore away blocks of lava, ice and scoria; the plain below was covered with dashing waves. Twelve miles from the mountain the waters still had a velocity of fifty-six feet per second, or about two-thirds of a mile a minute. Escape from such a current would be impossible. Six hundred houses were swept away and one thousand people destroyed. The sides of the cone glowed in the night with a reddish light. Cotopaxi also had a great eruption in 1533, which hurled lava blocks containing one hundred and thirty cubic yards to a distance of nine miles. Such masses would weigh more than two hundred and eighty tons. Such feats will serve to give clearer ideas of the immense power of volcanic action.

Perhaps a statement of the force required to raise a column of lava would interest the reader. Lava being about twenty-eight times as heavy as water, a column of it eleven and three-sevenths feet high, and one inch square, would weigh fifteen pounds. Then to raise lava to the tops of various volcanic cones would require pressure or initial velocity as follows:

Height.Pressure per
square inch.		Initial velocity
per second.
Stromboli2,168 feet.2,640 pounds.371 feet.
Vesuvius3,874“4,710“496“
Hecla5,106“6,195“570“
Ætna10,892“13,230“832“
Teneriffe12,464“15,135“890“
Mauna Kea14,700“17,865“966“
Popocatepetl17,712“21,525“1,062“
St. Elias18,079“21,975“1,072“
Cotopaxi18,869“22,380“1,104“
Sahama22,965“27,756“1,212“

When we remember that our powerful steam engines are operated by pressures varying from one hundred and twenty to two hundred pounds per square inch, it is evident we can have no adequate conception of the magnitude of a force of twenty-seven thousand pounds to the square inch. And yet such a power must be but a tithe of the force exerted; for it represents only the force necessary to throw the lava from the surface to the tops of the mountains; whereas the lava reservoirs are far beneath the surface. Also, the above calculation considers only the mere weight of the lava; it allows nothing for the resistance of cohesion, friction, or a heavy crust to be often burst through. When we consider all these, each of which must far surpass the weight of the single column of lava, it is evident that the pressure that can hurl lava blocks of two hundred and eighty tons nine miles from a mountain must reach a million pounds per square inch. These are meaningless figures. Human thought cannot grasp so stupendous a power.

Perhaps the best known of the great volcanoes are those of the Sandwich Islands. We find there the largest extinct crater in the world. The great dead crater of Haleakala, in East Maui, is thirty miles in circumference. The crater of Kilauea, on the flank of Mauna Loa, is about seven miles in circumference. Several great eruptions have occurred in these islands during the past fifty years; and in one of these convulsions the volume of lava poured out was at least equal to the great outburst of Skaptar Jokul in Iceland. And when we consider the frequent recurrence of the Hawaiian eruptions, it at once appears that in this region lies the greatest lava producer on the globe.

But in regard to destruction of life or property, there has so far been no more harmless region in the world. There are two reasons: The lava poured out is very liquid, and cools slowly; hence a cone formed from it has a very gradual slope. The actual grade of Mauna Loa is but five or six degrees. So a lava stream descends it very slowly; and the light on the mountain warns the people of the outbreak. The shore region is the only one inhabited, the interior being covered with dense forests. So the lava may burn a path directly through to the sea, and yet do no great damage to the interests of the people. The greatest damage done to the island has not been from an outpour of lava, but from earthquakes and sea-waves. The great eruption of 1868 was accompanied by continual shocks—two thousand being felt in a fortnight, and numerous tidal waves being produced; yet the total fatality was but one hundred, and nearly all of these were old or weak persons who were unable to swim well enough to escape from waves that overtook them. A few were overwhelmed by a torrent of soft, red clay that broke from a fissure in the mountain. Cliffs and crags were thrown down by the earthquakes, and the top of one hill was thrown one thousand feet. The lava stream reached the sea at Nanawale, fifty miles from its source, and pushed three-fourths of a mile into the sea.

Again, in an eruption in 1880, two lava streams poured out toward the town of Hilo; and though the great crater continued in full blast, it was nine months before the people could be sure whether the streams would destroy the town or not. At length the lava was within five minutes walk of the town. Many collected their chattels and left. Then the action on the mountain suddenly subsided; and in a few days the “great red dragon” lay stiff and cold, almost at the people’s doors.

Since the natives build their houses almost invariably of one story and of the lightest materials, earthquakes can do comparatively little damage to most property. Hence, with all the activity of the great volcanoes, the inhabitants are far more secure than those of many other regions apparently not so dangerous. Persons may readily visit the great crater in eruption, though at full blast; and excursion parties are organized to visit this “Niagara of fire” on every occasion of unwonted activity. Nowhere else in the world can volcanic action on the grandest scale be so carefully observed.