248 SCIENCE PROGRESS 



preceded the last eruption in 1302 were similar to those 

 which have occurred recently in the island and there is reason 

 to fear that the Ischian earthquakes of 1796, 1828, 1881 and 1883 

 are merely symptoms of underground activity which sooner or 

 later may result in forming a new lateral cone on the present 

 site of Casamicciola. 



Of most towns, especially of those which lie along the coast, 

 the partial removal is all that can be considered. A harbour 

 like that of San Francisco, which has no rival for hundreds of 

 miles and which lies close to the shortest route from Panama to 

 Yokohama and Shanghai, cannot be transferred. Nor can those 

 along the western coast of South America, subject though they 

 be to the inrush of seismic sea-waves. The utmost that can be 

 attempted in such cases is to shift the residential quarters 

 farther inland, just as, after the earthquake of 1692, Port Royal 

 was maintained as a naval station while the town of Kingston 

 arose in place of that which sank beneath the sea. The removal 

 of a town, however, is a remedy so desperate that it will seldom 

 be entertained ; and as the recent experience of Kingston has 

 shown it may not be altogether effectual. We must, therefore, 

 as a rule, avail ourselves of the alternatives at our disposal and 

 endeavour to mitigate the effects of earthquakes by the choice of 

 suitable sites and modes of building. 



As regards situation, it is clear that, in the absence of a 

 protecting sea-wall, low-lying land along shores that are liable 

 to be swept by seismic sea-waves should be avoided. All 

 buildings, especially lofty ones, should be erected on a rocky 

 foundation, never if otherwise possible on sand or gravel. Soft 

 friable beds resting on a slope of rock or forming the edge of a 

 cliff or steep river-bank are perhaps the worst of all foundations. 

 Not only is the shock more strongly felt on them than on the 

 adjoining rock but the beds as a whole may slide downwards or 

 forwards and be extensively fissured by the action of the shock. 



In all cases, however, even in those in which an inferior site 

 cannot be avoided, the loss of life may be diminished by erecting 

 only houses that are adapted to withstand the strain of an 

 earthquake shock. To erect a building that is comparatively 

 earthquake-proof and at the same time fire-proof is merely a 

 question of expense. The walls must be very strong at the base 

 and as light towards the top as may be consistent with strength ; 

 they must be firmly braced together by iron rods from front to 



