Disregarding for convenience the internal volcanic forces of the earth, let us take for granted that we have an unlimited supply of fused silicates at a very high temperature; what will be the changes and effects produced in the escape of such matters upon the earth's surface ?.

That, at the great sources of volcanic material the igneous mass is in a completely fused state there can hardly exist any doubt. By this is meant that the magma is an intimate mixture of various chemical elements and compounds that have not yet assumed any other than the fluid state, or, in other words, that the molecules move freely amongst each other and have not arranged themselves in any definite crystalline form.