Fig. 1. Monthly Distribution of Earthquakes. Charleston Statistics. 

 Total 395. 



In figure 1 we have almost a facsimile of figure 5, plate 

 7, in ^.Ir. Taber's drawing, but with our new^ adjustment of 

 seasons the curve takes on an increased significance. In 

 short, the line seems to be exactly fitted to the seasonal 

 scheme. Here we have the maximum frequency in the mid- 

 dle of the period assigned to the autumnal equinox, and a 

 minor rise in each of the other three seasons. The special 

 advantage of this plan is that it is based on a previously 

 assigned system ; that this system is formed on well estab- 

 lished periodic phenomena ; that we may reproduce the for- 

 mula for any year ; that, if this concurrence of seismic fre- 

 quency with the seasons assigned is sustained by a prepon- 

 derance of testimony, it points toward a generalization of 

 value, and that, behind that generalization, there may lie a 

 good and sufficient reason for seismic periodicit}'. 



Let us proceed to other statistics of earthquakes Avhich 

 may be subjected to the same test. The oldest table of seis- 

 mic frequency by months which I have at hand is one quoted 

 by Dr. Mallet in his treatise on earthquakes in the British 



40 



