64
THE ERUPTION OF PELÉE
ent in sufficient measure in the exploding cloud of the main eruption to have caused, through toxic inhalation, the deaths of a t least a large portion of the population. Other gases found were nitrogen, oxygen, carbonic acid, hydrogen, methane, and argon, the last two also found among the gases of the waters of Luchon (address to the Académie des Sciences of Paris, December 15, 1902; Revue Scientifique, J a n u a r y 3, 1903).* I have always felt t h a t electric discharges m u s t have also been responsible for the destruction of some life; indeed, the case could hardly have been otherwise, for, as we are informed b y competent witnesses, the death-dealing cloud was charged with electricity, short flashes passing a t rapid intervals from point to point. This same feature was also observed in the descending cloud of June 6, and Flett and Anderson refer to it in their description of the cloud of July 9, 1902. During m y second visit to Martinique I was informed, b y one who was saved from the destruction of Ajoupa-Bouillon (although losing his family in t h a t terrible disaster of August 30), t h a t the descending cloud t h a t wrought the havoc was flashing with electric lines and sparks, resembling artificial fireworks. M. Lacroix, in his earlier reports and in his concluding work, " L a Montagne Pelée et ses Éruptions," finds no evidence of the destroying work of electricity in the eruption of May 8, and concludes t h a t this agent played no appreciable p a r t in the destruction of Saint-Pierre's inhabitants. The arguments and negative evidence of a late day which are brought forward to support his position seem to me wholly inconclusive. (See also Lacroix's article " Pompéi, Saint-Pierre, Ottajano," in the Revue Scientifique, Oct. 20,1906, p. 485.) I have elsewhere expressed m y view t h a t the destruction of Pompeii was in all probability caused b y a volcanic discharge similar to t h a t which brought * The a p p r o x i m a t e percentages of some of these gases, obtained from a later analysis, were: nitrogen, 55; carbonic acid, 15; oxygen, 14; hydrogen, 8 (Moissan, in La Science au XX Siècle, March, 1903). The t e m p e r a t u r e of t h e issuing gases was a b o u t 400° C. Gautier has shown t h a t almost precisely t h e same gases m a y be obtained b y heating to redness t h e ordinary crystalline rocks (Revue Scient., J a n . 17; also Comptes Rendus, 1901, vol. 132, pp. 58 et seq. Moissan has since found t h e carbon oxyd gas in large proportion a m o n g t h e fumarole products of t h e Soufrière of Guadeloupe. I t is interesting t o n o t e t h a t Boussingault, from observations m a d e upon t h e volcanoes Tolima, Quindi , Puracé, Pasto, Tuqueres, a n d Cumbal, of t h e E q u a t o r i a l Andes, found t h a t their chief gaseous e m a n a t i o n s were watervapor a n d carbonic acid, t h e sulphurous acid present being considered accidental; a n d it is r e m a r k e d t h a t even where t h e odor of sulphur is strongly felt t h e actual q u a n t i t y of the gas present is very small when compared with carbonic acid (Annales de Chimie et de Physique, vol. L I I , p. 23, 1833). Bunsen also found t h a t carbonic acid v a s t l y p r e p o n d e r a t e d a m o n g t h e gaseous exhalations of t h e Iceland volcanoes. Albert B r u n a n d A. J a q u e r a d h a v e d e t e r mined t h e presence of hydro-carbons in t h e ash of Vesuvius (Sept. 25, 1904), a n d t h e y claim t h a t their reaction on silicated carbons (like petroleum), b y heating, would sufficiently explain all volcanic p h e n o m e n a (Archives des Sciences Physiques et Naturelles, June, 1905, p. 416). These investigators, singularly enough, as a result of their e x a m i n a t i o n of t h e p r o d ucts of eruption (the dry ash, scoriæ a n d lava), assume t h a t s t e a m plays no i m p o r t a n t p a r t in t h e agency of volcanoes, a n d affirm t h a t the familiar white p e n n a n t or " s t e a m - c l o u d " of volcanoes is not s t e a m a t all, b u t a chlorid gas! (Op. cit., pp. 439 et seq.; pp. 589 et seq.) e