Eruption of Vesuvius, 1867-8. 29 



wearing down its enemy by slow torture, and spreading out the 

 stripped spoils over its own depths ; now receiving them in more 

 abundant measure from the rivers, or carving for itself at once 

 huge slices of the yielding sandclifF, There is, it is said, sufficient 

 power at work, and it has been long enough at work, to have 

 reduced all the continents and islands of the globe to powder, and 

 to have strewed them over the bed of the ocean. It is plain, then, 

 that there must be compensation somewhere. Earth must have 

 its revenge. Where then are we to look for the process of resto- 

 ration .'' It is the volcano and the earthquake that are the rough 

 but kind restorers of earth's losses. And they work not by fits 

 and starts merely. Though their energy is more visible at one 

 time than another, yet the work of restoration is continually going 

 on somewhere in the world. Not always in the shape of sudden 

 upheavals of new soil — like the sudden apparition of Monte Nuovo 

 in the middle of Lake Averno, which took place in 1538 ; or the 

 elevation of the whole coast-line of Chili and the chain of the 

 Andes (seven feet in a night), which happened only forty-six years 

 ago — but the process is in some quarters of the globe continuous 

 however slow. For instance, Norway and Sweden, with the rest 

 of the Scandinavian region, are rising out of the sea at the rate of 

 two feet per century. Thus, then, there is a great cycle of change 

 — " Omnia mutantur nihil interit?" — and in this cycle of change the 

 volcano and the earthquake in reality play the part of conservatives. 

 But secondly, what is the power which sets these agents in motion ? 

 The answer lies of course in the fact of the earth's central heat. 

 Whether or no the interior of the globe be an ocean of melted 

 matter, or a solid mass unable to melt from the enormous pressure 

 to which it is subjected, thus much is certain, that at twenty miles 

 depth the earth is in all probability red hot, and beyond this 

 depth there are seas, or possibly one vast ocean of molten mineral 

 substance. We know also that there is water in abundance, and 

 sulphur, and other vaporizable substances, condensed by the 

 pressure exerted upon them. What will be the effect when the 

 earth's crust is thinned by the spoliation I have described ? Just 

 imagine the gigantic power of the imprisoned gases ready to take 

 advantage of any weak quarter. Why, it is plain that cracks must 

 occur sooner or latei*, and that when this happens up will go the 

 land on the light side, and down on the heavy side ; and this is 

 just what happens when an earthquake takes place. The land is 

 seen to rise ; the sea coast, and often a large tract in the bed of 

 the ocean subsides ; and just as water oozes through cracks in ice, 

 so the lava, which is nothing but fused mineral substance, creates 

 for itself a vent in a new volcano, or avails itself of an old one, 

 with this great difference, that the outburst of the lava is rendered 



