Being the opening address to section III (vulcanology) of the international geographical congress.Extrated from the Geological Magazine, n.s. Decade V, Vol. VI, October, 1909.London, Dulau n.d. vers 1909. 11 pages + 2 planches hors-texte et 1 schéma dans le texte. Cahier cousu. Bon état. Format in-8° (22x14).