I have quoted this graphic account of the great volcanic eruption of St. Vincent in 1812 from Canon Kingsley's delightful work to impress on my readers, in more eloquent language than I can command, the fact of great explosions having taken place in recent times similar in character, though much inferior in extent and force, to that by which I believe the great basin of the Lake of Masaya and similar basins in the same and adjoining Pacific provinces have been blasted out. I do not shut my eyes to the fact that great as was the force in operation in 1812 at St. Vincent, that necessary to excavate the great chasm at Masaya was incomparably greater. No one is more disinclined than I am to invoke the aid of greater natural forces in former times than are now in existence. But I believe there is good reason to infer that at the close of the glacial period volcanic energy was much more intense than now. So strained is the earth's crust at some parts that it is surmised that even a great difference in the pressure of the atmosphere such as occurs during a cyclone, may be sufficient to bring on an earthquake or a volcanic eruption already imminent. Whether this be so or not, there can be no doubt that at the melting away of the ice of the glacial period there was an enormous change in the strains on the earth's crust. Ice that had been piled up mountains high at the poles and along the chain of the Andes all through tropical America melted away and ran down to the ocean beds. This great transference of weight could not have been accomplished without many rendings of the earth's crust and many outpourings of lava and volcanic outbursts. Let us reflect, too, that not only was an enormous mass of matter, before lying over the poles, removed nearer to the equator, and many mountain-chains relieved of the ice of thousands and tens of thousands of years, but that there must have been an actual change in the earth's centre of gravity. All our experience shows that the ice was more developed on some meridians than others; probably nowhere in the whole world did it lie so thick as along the American continents; and everywhere it must have been greater over the land than over the sea. When it assumed its liquid form, and arranged itself freely according to its specific gravity, the centre of gravity of the earth must have been effectively changed. All who have studied the present statical condition of the earth's crust will readily admit that such a change might produce greater volcanic outbursts than any known to history.