E. O. HOVEY. The New Cone of Mont Pelée and the Gorge of the Rivière Blanche, Martinique, Am. Jour. Sci., vol. 16, 1903, pp. 269-281, pls. 11-14. A. HEILPRIN. The Tower of Pelée. Philadelphia, 1904, pp. 62, pls. 22. A. LACROIX. La montagne Pelée et ses éruptions, Acad. des Sciences, Paris, 1904, Chapter iii. KARL SAPPER. In den Vulkangebieten Mittelamerikas und Westindiens, Stuttgart, 1905, pp. 172-178. A. C. LANE. Absorbed Gases of Vulcanism, Science, N.S., vol. 18, 1903, p. 760. G. K. GILBERT. The Mechanism of the Mont Pelée Spine, _ibid._, vol. 19, 1904, pp. 927-928. I. C. RUSSELL. Pelée Obelisk once More, _ibid._, vol. 21, 1905, pp. 924-931. The dissection of volcanoes:— J. W. JUDD. Volcanoes, Chapter v. S. SEKYA and Y. KIKUCHI. The Eruption of Bandai-San, Trans. Seis. Soc., Japan, vol. 13, Pt. 2, 1890, pp. 140-222, pls. 1-9. R. D. M. VERBEEK. Krakatau. Batavia, 1885, pp. 557, pls. 25. ROYAL SOCIETY. The Eruption of Krakatoa and Subsequent Phenomena. London, 1888, pp. 494. G. K. GILBERT. Report on the Geology of the Henry Mountains, U.S. Geogr. and Geol. Surv., Rocky Mt. Region, Washington, 1877, pp. 22-60. SIR A. GEIKIE. Ancient Volcanoes of Great Britain, vol. 2 especially. D. W. JOHNSON. Volcanic Necks of the Mount Taylor Region, New Mexico, Bull. Geol. Soc. Am., vol. 18, 1907, pp. 303-324, pls. 25-30. CHAPTER XI THE ATTACK OF THE WEATHER =The two contrasted processes of weathering.=—It has already been pointed out that change and not stability is the order of nature. Within the earth’s outer shell and upon it rock alteration goes on continually, and from some portions of its surface the changed material is as constantly migrating to neighboring or even far distant regions. Before such transportation can begin the hard rock must first be broken down and reduced to fragments which the transporting agencies are competent to move. To accomplish this breaking down, or _degeneration_, of the rock masses, either a wide range in temperature or chemical reaction is essential. In the atmosphere are found such active chemical agents as oxygen and carbon dioxide, the so-called carbonic acid gas; and these agents in the presence of water react chemically with the minerals of the rocks and form other minerals such as the hydrates and carbonates, which are lighter in weight and more soluble. This _chemical_ attack upon the outer shell of the lithosphere is described as _decomposition_.