493 



determined by the dip or slope of the subjacent beds of rock. Earth 

 fissures are never produced by the direct passsage of the wave of 

 shock. They are a mere secondary result, and are no more than 

 incipient landslips. 



2. Rock shattering and falls. 



3. Alterations of water- courses, muddying of springs, &c., all of 

 which are shown to be due to the secondary effects of landslips into 

 their beds, falls of partially loose rock therein producing ponding up 

 and subsequent debacle. 



The total modifying effects on the earth's surface are shown to be 

 insignificant. 



No great sea-wave accompanied this shock ; nor was such possible, 

 the focal point being inland. The author examined with care more 

 than 150 miles of sea-coast, as well as river-courses, for evidence of 

 any permanent elevation of land having taken place concurrently 

 with this earthquake, but found none. Earthquakes cannot produce 

 elevations, although the latter have been known to have taken place 

 about the same time as earthquakes and in the same region. 



t. Discusses the meteorological phenomena, both during the earth- 

 quake or directly after it, and for a prolonged period before it. 

 Some remarkable relations are pointed out between the disturbance 

 of the annual rainfall previously and the occurrence of shocks. 



The physical conditions concerned in widely alleged unusual 

 meteoric light, diffused over the central portion of the shaken region 

 at the night of the shock, and of the occurrence of oppressive heat, 

 &c., are discussed ; and under u, the premonitory and other effects on 

 lower animals, of nausea in men, &c., are considered. 



v. Points out that the method of investigation pursued, enables 

 deductions even now to be drawn from ancient fissures, &c., as to the 

 focal centres of earthquakes occurring at very remote periods. In 

 map D, the lines of loci of the focal points for the whole of the 

 Italian peninsula are, as far as practicable, laid down, and their 

 general connexion with the seismic bands of the Mediterranean 

 Basin (as deduced from the British Association Earthquake Cata- 

 logue, and its accompanying Seismological Map of the World) is 

 pointed out ; and some general relations both of the unequal distri- 

 bution of the points of greatest energy along these seismic bands, 

 and of the unequal evolution of energy at the same points, in long 



