Is it not quite evident that this gallery was formerly the outlet for the pent-up lava in the interior of the earth, and that these eruptive matters t...

The difference evidently depends on the conductibility of certain rocks. In the neighborhood of an extinct volcano, it has been remarked that the elev...

Thus at Yakoust in Siberia, it has been remarked that the heat increases a degree every thirty-six feet. The difference evidently depends on the condu...