[23] Modern Painters.

[24] Modern Painters.

[25] See papers by the writer on Volcanoes and Volcanic Action in "Knowledge" for May and June, 1891, on which this chapter is partly based.

[26] Perhaps these Scripture phrases were suggested long before the Bible was written, by the sight of some crater in active eruption.

[27] The Hawaiian Archipelago.

[28] "The Crest of the Continent," by Ernest Ingersoll, Chicago, 1885.

[29] Scenery of Scotland page 130, new edition.

[30] Bonney.

[31] Scenery of Scotland, page 201, new edition.

[32] Geikie.