l8 ABOUT VOLCANOS AND EARTHQUAKES. 



just what was seen to happen in ]\Iessina i: the great 

 Cdabrian earthquake. As the shock ran along the 

 ground, the houses of the Faro were seen to topple 

 down in succession ; beginning at one end and running 

 on to the other, as if a succession of mines had been 

 sprung. In the earthquake in Cutch, a sentinel standing 

 at one end of a long straight line of wall, saw the wall 

 bow forward and recover itself; not all at once, but with 

 a swell like a wave running all along it with immense 

 rapidity. In this case it is evident that the earthquake 

 wave must have had its front oblique to the direction of 

 tJie wall (just as an obliquely-held ruler runs along the 

 edge of a page of paper while it advances, like a wave of 

 the sea, perpendicularly to its own length). 



(25.) In reference to extinct volcanos, I may just 

 mention that any one who wishes to see some of the 

 finest specimens in Europe may do so by making a 

 couple of days' railway travel to Clermont, in the depart- 

 ment of the Puy de Dome in France. There he will 

 find a magnificent series of volcanic cones, fields of ashes, 

 streams of lavas, and basaltic terraces or platforms, 

 proving the volcanic action to have been continued for 

 countless ages before the present surface of the earth 

 was formed ; and all so clear that he who runs may read 

 their lesson. There can there be seen a configuration 

 of surface quite resembling what telescopes show in the 

 most volcanic districts of the moon. Let not my hearers 

 be startled : half the moon's face is covered with unmis- 

 takable craters of extinct volcanos. 



(26.) Many of the lavas of Auvergne and the Puy dz 



