148 



MR. R. D. OLDHAM ON THE PROPAGATION OF 



be taken as the epicentre for the purpose of calculating distances. The time of 

 origin was ll h 5 m G.M.T., with a maximum error of not more than 0'5' n , and probably 

 uot more than half of this. 



As the records have teen discussed in my report on this earthquake (' Mem. 

 Geol. Surv. Ind.,' vol. 29) it is not necessary to repeat the details here. The times 

 are tabulated here on a slightly different principle to that adopted in the report, and 

 some slight changes have been made where the times as finally determined and 

 published in the ' Boll. Soc. Sismol. Ital.,' vol. 3, Part II., differ from those originally 

 communicated to me. They are given in minutes after II 1 ' G.M.T. 



The times of the second and third phases at the Rocca di Papa and Padua are 

 taken from copies of the original traces, they do not appear in the accounts as 

 printed in the ' Boll. Soc. Sismol. Ital.,' vol. 3, Part II. The time at Siena is taken 

 from the account and photograph of the trace sent to me from that observatory. In 

 the ' Boll. Soc. Sismol. Ital.,' it is printed as 7 m 48 s , probably a misprint ; the time at 

 Verona is there given as 8" 1 , also a probable clerical or printer's error. 



The time of the maximum of the third phase on the N. S. component of the 

 three-pendulum instrument at Ischia, 57 h 3 m , is much later than any of the others. 

 This may be due to the direction of its sway ; a maximum of 4 '5 millims. is recorded 

 at 48'l m , but is exceeded by that of 57'3 m which reached 8'4 millims. This record 

 may be excluded from consideration. 



The Grenoble and Potsdam records are so divergent from the others that they 

 had best be excluded from consideration. They probably correspond more or less to 

 the maximum of the first phase as registered on the Italian instruments. 



