N.E 



5 













.£ 



i 







3 



D 







.G 



"H 











^-^v 



u. 



1863 



1822 



1767 



A.D.79 to 163 1 



o 5.W. 



N.E. 



S W. 



B.C-63 



Fig. 31. — Five successive stages in the change of form of Vesuvius (after 

 Phillips' "Vesuvius," Oxford, 1869). In the oldest (lowest figure) we 

 see the mountain with its still earlier outline completed by the cone 

 drawn in dotted line. Within the period of historic record that cone 

 had not been seen. The mountain had, so far as men knew, always 

 been truncated as shown here and in Fig. 30. The next figure above 

 shows the further lowering of the mountain by the first eruption on 

 record — that which destroyed Pompeii in a.d. 79. The commencing 

 formation of a new ash-cone is indicated by a dotted line. In the three 

 upper figures we trace the gradual growth of the new cone from 1631 to 

 1868. In 1872 the top of the new ash-cone was blown away, and the 

 mountain reverted to the shape of 1822. Now (1920) the cone has 

 accumulated once more and is higher than it was in 1868. 



