Stromboli 2,168 feet. 2,640 pounds. 371 feet. Vesuvius 3,874 “ 4,710 “ 496 “ Hecla 5,106 “ 6,195 “ 570 “ Ætna 10,892 “ 13,230 “ 832 “ Teneriffe 12,464 “ 15,135 “ 890 “ Mauna Kea 14,700 “ 17,865 “ 966 “ Popocatepetl 17,712 “ 21,525 “ 1,062 “ St. Elias 18,079 “ 21,975 “ 1,072 “ Cotopaxi 18,869 “ 22,380 “ 1,104 “ Sahama 22,965 “ 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.