A map of the moon... should be in every geological lecture room; for no where can we have a more complete or more magnificent illustration of volcanic operations. Our sublimest volcanoes would rank among the smaller lunar eminences; and our Etnas are but spitting furnaces.

Each volcano is an independent machine—nay, each vent and monticule is for the time being engaged in its own peculiar business, cooking as it were its special dish, which in due time is to be separately served. We have instances of vents within hailing distance of each other pouring out totally different kinds of lava, neither sympathizing with the other in any discernible manner nor influencing other in any appreciable degree.

If I was to establish a system, it would be, that Mountains are produced by Volcanoes, and not Volcanoes by Mountains.

May not subterraneous fire be considered as the great plough (if I may be allowed the expression) which Nature makes use of to turn up the bowels of the earth?

Our earth is very old, an old warrior that has lived through many battles. Nevertheless, the face of it is still changing, and science sees no certain limit of time for its stately evolution. Our solid earth, apparently so stable, inert, and finished, is changing, mobile, and still evolving. Its major quakings are largely the echoes of that divine far-off event, the building of our noble mountains. The lava floods and intriguing volcanoes tell us of the plasticity, mobility, of the deep interior of the globe. The slow coming and going of ancient shallow seas on the continental plateaus tell us of the rhythmic distortion of the deep interior-deep-seated flow and changes of volume. Mountain chains prove the earth's solid crust itself to be mobile in high degree. And the secret of it all—the secret of the earthquake, the secret of the 'temple of fire,' the secret of the ocean basin, the secret of the highland—is in the heart of the earth, forever invisible to human eyes.

The fire at Lipara, Xenophanes says, ceased once for sixteen years, and came back in the seventeenth. And he says that the lavastream from Aetna is neither of the nature of fire, nor is it continuous, but it appears at intervals of many years.