28 Eruption of Vesuvius, 1867-8. 



with all the bubbling fury of its new birth. Once and again, we 

 were baffled for the furnace was seven times hot, and it needed 

 courage even to catch a glimpse. But there it was, welling out of its 

 fountain in the slope of the volcano, now cleaving, by its very heat, a 

 channel for itself in the lava of former eruptions ; now arching 

 over its own narrow bed by the splashing of vitrified matter. 

 Some fifty yards lower down we watched the flow with more 

 comfort to ourselves where the crevice was broader, and the stream 

 already cooler ; here it issued from beneath such an arch as I have 

 described, was joined, as it seemed, by a fresh current bubbling up 

 from beneath, and disappeared once more under an arch similar 

 to the first. And here we boiled our eggs, and imbedded our 

 pence, while the sun set kindly, adding not a little to the already 

 weird effect of the scene. Our descent of the cone was rapid ; 

 for we galloped down a shoot of cinders in three or four minutes. 

 Darkness overtook us in the Atrio del Cavallo, and when we 

 passed once more to the north-west side of the mountain, the 

 lava streams were glowing brightly as at our first midnight visit. 



And now, that we have made ourselves acquainted with some 

 of the prominent phenomena of an eruption, let us enquire what 

 it all means. Numberless questions there are of great interest 

 one would like to have answered. I wish I could do more than 

 reply to a few of the most elementary. What are volcanos .'' Do 

 they serve a useful purpose in the economy of nature, or are they 

 simply destructive ? Why are they found where they are ? What 

 are the laws which regulate the recurrence and the intensity of 

 eruptions? What is lava? — its composition, its motion, its pro- 

 perties ? Let me try to throw a little light on these points in as 

 brief a compass as possible. We may start, I think, with the 

 assumption that nothing in nature is useless ; even what seems 

 most destructive of that harmony we cannot doubt to be in 

 accordance with the mind of the Creator, on closer inspection, is 

 found to be part of a grand scheme of compensation without which 

 there would be no unity at all. 



It is the business of science to touch these elements of destruc- 

 tion with the wand of order, and to show that the beast that preys, 

 the storm that uproots, the volcano that overwhelms, have their 

 places, too, in the harmony of creation, and work to a beneficent 

 end. The old Ionic philosopher, who said that " Strife was the 

 parent of all," unconsciously uttered a deep scientific truth, and in 

 no province of ci'eation is that truth more strikingly illustrated 

 than where geology notes the everlasting strife of sea and land. 

 Wherever these two elements meet, there is no peace ; yet the war 

 is unequal. Whether the coast-line be chalk, or sand, or hard 

 rock, no matter, earth must give way, and the sea triumphs ; now 



