Revieios — Geilde's Ancient Volcanoes of Great Britain. 327 



In the opening chapter the author traces the influence of volcanoes 

 and volcanic activity upon the mythology of the early Greeks and 

 Komans, and points out the many opportunities which the dwellers 

 along the basin of the Mediterranean must have had of observing 

 these most striking and startling phenomena of nature. 



" When in later centuries the scientific spirit began to displace 

 the popular and mythological interpretation of natural phenomena, 

 the existence of volcanoes and their extraordinary phenomena offered 

 a fruitful field for speculation and conjecture. As men journeyed 

 outwards from the Mediterranean cradle of civilization, they met 

 with volcanic manifestations in many other parts of the world. 

 When they eventually penetrated into the Far East, they encoun- 

 tered volcanoes on a colossal scale and in astonishing abundance. 

 When they had discovered the New World, they learnt that in that 

 hemisphere also ' burning mountains ' were numerous and of 

 gigantic dimensions. Gradually it was ascertained that vast lines 

 of volcanic activity encircle the globe. By slow degrees the volcano 

 was recognized to be as normal a part of the mechanism of our planet 

 as the rivers that flow on the terrestrial surface. And now at last 

 men devote themselves to the task of critically watching the opera- 

 tions of volcanoes with as much enthusiasm as they display in the 

 investigation of any other department of nature. They feel that 

 their knowledge of the earth extends to little beyond its mere outer 

 skin, and that the mystery which still hangs over the vast 'interior 

 of the planet can only, if ever, be dispelled by the patient study of 

 those vents of communication between the interior and the surface. 



" If, however, we desire to form some adequate idea of the part 

 which volcanic action has played in the past history of the earth, we 

 should be misled were we to confine our attention to the phenomena 

 of the eruptions of the present day. An attentive examination of 

 any modern volcano will convince us that of some of the most 

 startling features of an eruption no enduring memorial remains. The 

 convulsive earthquakes that accompany a great volcanic paroxysm, 

 unless where they actually fissure the ground, leave little or no trace 

 behind them. Lamentably destructive as they are to human life 

 and property, the havoc which they work is mostly superficial. In 

 a year or two the ruins have been cleared away, the earth-falls have 

 been healed over, the prostrated trees have been removed, and, save 

 in the memories and chronicles of the inhabitants, no record of the 

 catasti'ophe may survive. The clouds of dust and showers of ashes 

 which destroyed the crops and crushed in the roofs of the houses 

 soon disappear from the air, and the covering which they leave over 

 the surface of a district gradually mingles with the soil. Vegetation 

 eventually regains its place, and the landscape becomes again as 

 smiling as before. 



" Even where the materials thrown out from the crater accumu- 

 late in much greater mass, where thick deposits of ashes or solid 

 sheets of lava bury the old land-surface, the look of barren desola- 

 tion, though in some cases it may endure for long centuries, may in 

 others vanish in a few years. The surface-features of the district are 



