THE CAUSE OF EARTHQUAKES. 287 



6. The concurrence of the * centrifugal force ' of the 

 earth with the last quarter of the moon. 



7. The entrance of the moon on the ecliptic — the 

 so-called nodes. 



Assuming that earthquakes are wholly consequent on 

 these attractions, it at once becomes possible to predict 

 their occurrence. This Falb does, and when his predic- 

 tions have been fulfilled he has certainly gained notoriety. 



He commenced by the predictions of great storms. 

 In 1873 he predicted the destructive earthquake of 

 Belluno, which earned for himself a eulogistic poem, which 

 he has republished in his * Gedanken und Studien iiber 

 Vulcanismus.' After this, in 1874, he predicted the erup- 

 tion of Etna. He also explained why, in B.C. 4000, there 

 should have been a great flood, and for a.d. 6400 he 

 predicts a repetition of such an occurrence. 



When we approach the question of the extent to which 

 the attraction of the sun and moon may influence the 

 production of earthquakes, a question which we have to 

 answer is, whether it is likely that the attractive power 

 of the moon is so great that it could draw up the crust of 

 the earth beyond its elastic limits. We know what it 

 can do with water. It can lift up a hemispherical shell 

 8,000 miles in diameter about two or three feet higher 

 at its crown than it lifts the earth. Even supposing the 

 solid crust to be lifted 100 times the apparent rise of the 

 tide, is it likely that a hemispherical arch 8,000 miles in 

 diameter when it is raised 200 feet at its crown could by any 

 possibility suffer fracture ? If an arch is 12,000 miles in 

 length, all that we here ask is, whether the materials 

 ^hich compose the arch are sufficiently elastic to allow 

 themselves to be so far stretched that the crown may be 

 raised 200 feet. The result which we should arrive at is 

 apparently so obvious that actual calculation seems hardly 



