A FORECAST OP THE END 119 



ocean beneath. On the other hand, some of our 

 English astronomers still regard them as real volcanoes, 

 and possibly the sources that have shot out into space 

 great numbers of wandering blocks of stone and metal. 

 I have seen Vesuvius shoot up white-hot rocks weighing 

 sixty tons, as if they were pebbles, and can appreciate 

 the point; but the whole question has still to be 

 discussed with great reserve, and we must draw no 

 inferences. 



In point of fact, our volcanoes are rather in the nature 

 of safety-valves, As is well known, they lie largely 

 along two lines on either side of the Pacific, and seem to 

 indicate weaker seams or fissures in the crust. Through 

 these vents unhappy as it is for the local inhabitants 

 the pressure below is occasionally eased by the discharge 

 of gases and molten rock. Earthquakes are frequent 

 along the same lines of weakness. Some astronomers 

 have gone so far as to suggest that the deep bed of the 

 Pacific Ocean represents the spot from which the lunar 

 material was torn ages ago ; though it is more likely that 

 the earth was then plastic enough to resume its shape. 

 At all events, the geological record suggests that 

 volcanic activity is decreasing as the earth grows older. 

 It must have been incessant in the early stages, and 

 there were great outbreaks in connection with the rise 

 of mountains at the periods we described. Quite late in 

 the Quaternary epoch the face of France was illumined 

 by the glare of volcanoes. There is no ground for 

 anticipating any great development of volcanic or 

 seismic activity. 



As to our second alternative, collision, there is just as 

 little ground for anticipation, but a much wider margin 

 for accident. One or two writers have lately, and more 

 or less playfully, suggested the possibility of collision 

 with a comet. The feelings of men in regard to comets 



