150 



MR. R. D. OLDHAM ON THE PROPAGATION OF 



ponent, the earlier stages of the disturbance are very ill marked, O' 1 59 com- 

 mencement of the slow undulations, maximum between I 1 ' 3'" 56" and l h 8 m 12*. 



Rocca di Papa. Hor. peudula ; E. W : O h 24"' 52" commencement, O' 1 35 ra 20 s 

 a maximum, O' 1 45'" another maximum ; I 1 ' O" 1 commencement of a group of great 

 undulations, maximum l h 6 m 40 s , end 2 h 15; N. S. : O 1 ' 34 m commencement, I 1 ' O m 

 commencement of slow undulations, l h 8 m 10* maximum. 



Grande sismom. ; E. W: O' 1 32 m 10 s commencement, O 1 ' 45 m 10" commencement 

 of undulations of 7' period l h 8 m 40" maximum, end about 2 h ; N. S. : O h 32 m 40' com- 

 mencement, O 1 ' 45 m commencement of slow undulations of 7 9 period, maximum 

 l h 8 m 30 s , end 2 h 12'". 



Ischia. Hor. pendula ; N. S. : O 1 ' 24 33" commencement, O 1 ' 35 14 s slower 

 oscillations, O h 55 m 18' commencement of very slow oscillations, I 1 ' 9 m 30 s maximum, 

 3 1 ' 12 m end ; E. W. : O h 24 49 s commencement, O h 33 m 20' resumption, O h 35 m 22" 

 slower oscillations, O h 54 m 7 s commencement of very slow oscillations, I 1 ' 8 m 39* 

 maximum, 3 h O m end. 



Catania. N.E. -S.W. component; O 1 ' 24 ra 53 s commencement, O 1 ' 35 m 4 s increase of 

 movement, O h 42 m 3 s commencement of slow undulations, l h 8 m 38 s maximum, 3' 1 3 m 26 8 

 end ; N.W.- S.E. : O h 24 m 35 s commencement, O h 53 m 49 s commencement of slow 

 undulations, I 1 ' ll m 5 9 maximum, 3 1 ' 5 m 2'8 8 end. 



Tabulating as before we obtain the following times, in minutes after O h , for the 

 different phases of the disturbance r 



This is a singularly complete record, almost as much so as that of the great 

 earthquake of June 12, 1897, and is besides remarkable for the very well defined 

 maximum of the great undulations. The time of commencement of the disturbance 



