8 EARTHQUAKES. 



speculations with few and imperfect facts for their 

 foundation. 



Among the efforts which have been made in modern 

 times to raise seismology to a higher level, is that of 

 Professor Perrey, of Dijon, who commenced in 1840 a 

 series of extensive catalogues embracing the earthquakes 

 of the world. These catalogues enabled Perrey, and 

 subsequently Mallet in his reports to the British Asso- 

 ciation, to discuss the periodicity of earthquakes, with 

 reference to the seasons and to other phenomena, in a 

 more general manner than it had been possible for pre- 

 vious workers to accomplish. The facts thus accumulated 

 also enabled Mallet to discuss earthquakes in general, 

 and the various phenomena which they present were sifted 

 and classified for inspection. Another great impetus 

 which observational seismology received was Mr. Mallet's 

 report upon the Neapolitan earthquake of 1857, in which 

 new methods of seismic investigation were put forth. 

 These have formed the working tools of many subsequent 

 observers, and by them, as well as by his experiments 

 on artificially produced disturbances. Mallet finally drew 

 the study of earthquakes from the realms of speculation 

 by showing that they, like other natural phenomena, 

 were capable of being understood and investigated. 



In addition to Perrey and Mallet, the nineteenth 

 century has produced many writers who have taken a 

 considerable share in the advancement of seismology. 

 There are the catalogues of Von Hoff, the observations of 

 Humboldt, the theoretical investigations of Hopkins, the 

 monographs of Schmidt, Seebach, Lasaulx, and others; 

 the books of Fuchs, Credner, Vogt, Volger ; the records 

 and observations of Palmieri, Bertelli, Eossi, and other 

 Italian observers. To these, which are only a few out of 

 a long list of names, may be added the publications of the 



