Penny Blood: Serial Sensation and Working-Class Entertainment — page 257: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

CHAPTER XIX. THE VOLCANO IN ERUPTION. Theories of voleanic eruption—Scrope, Dutton, Mallet—Local and temporary in- crease of temperature not probable—Richthofen’s theory unsatisfactory—Ex- planation of phenomena on hypothesis of fluid substratum in igneo-aqueous fusion—Amount of water-substance beneath vent probably variable—Mechantics of an eruption—Estimate of amount of water-substance in magma—Eruption, how brought to an end—Evisceration of cone—Siate of intermediate activity— Stromboli—Unsympathetic craters—Richthofen's difficulties met—Renewal of activity—Comparison with Geyser. Tue theory of the existence of an intensely hot substratum of rock in a state of igneo-aqueous fusion, underlying a crust of about 25 miles thickness, seems on the whole to offer the conditions calculated most readily to explain volcanic pheno- mena. The alternative view may fairly be stated to consist in the hypothesis that periodical local increments of temperature occur beneath volcanic areas, temporarily fusing the rocks, and causing their eruption. This was Scrope’s opinion’; Captain - Dutton holds the same view, viz. “that the proximate cause of eruptions is a local increment of subterranean temperature, whereby segregated masses of rocks, formerly solid, are liquified”’*. Neither of these writers attempts to explain the cause of the supposed increment of temperature. Mr Mallet’s theory, discussed in the preceding chapter, is of the same kind, except that he proposes to account for the local and periodical ele- vation of temperature by mechanical means. In whatever way 1 «¢ Volcanoes,” p. 263. 2 “Geology of the High Plateaus of Utah,” p. 120. Washington, 1880, COLA @ NOOKS ACO