392 



SEE— THE NEW THEORY OF EARTHQUAKES [November 15 



any elaborate notice; yet we may briefly point out the weakness of 

 the position taken, which seems to be the same as that announced 

 by Professor Mihie in his Bakerian Lecture to the Royal Society, 

 1906, where he says : 



" If we take a chart showing the varying position of 'our earth's north 

 pole in relation to its mean position, we see that the secular movement of 

 the pole is by no means uniform. Although it may at times follow a path 

 about its mean position which is approximately circular, at other times there 

 are comparatively sharp changes in direction of motion which may even 

 become retrograde. If now on a chart of this description we mark the time 

 positions of very large earthquakes, we find that they cluster around the 

 sharper bends of the pole path." (See the accompanying figures with ex- 

 planations taken from Professor Milne's paper.) 



■fofio 



-dTu) 



0.00 



♦o"io 



♦aso^. 



+CC50 



+0.30 +0:20 +6.10 55o ^aSo :^aSo I^o&o 



" Fig. I. After Th. Albrecht. The path of the North Pole from 1892 to 

 1894 inclusive. Each year is divided into tenths or periods of 36.5 days. 

 Numerals indicate the number of large earthquakes which occurred in each 

 of these divisions, commencing with the third tenth of 1892." 



"In a period of nearly 13 years (1892 to 1904) I find records for at 

 least 750 world-shaking earthquakes, which may be referred to three periods 

 continuous with each other, and each two tenths of a year or Ji days' dura- 

 tion. The first period occurs when the pole movement followed an approxi- 

 mately straight line or curve of large radius, the second equal period when 

 it was undergoing deflection or following a path of short radius, and the 

 third when the movement was similar to that of the first period. The num- 

 bers of earthquakes in each of these periods taken in the order named were 



