HoGBEN. — The Tasmanian Earthquake. 599 



taking the times for Kiama, Kiaiidra, Launcesfcon, Hobart, 

 with a velocity of twenty miles per minute. Bombala, Laun- 

 ceston, Hobart give C35, with a velocity of thirty-five miles per 

 minute. This also agrees to about a minute with Campbell- 

 town, Wilson's Promontory, Kiama, and Kiandra. Still more 

 nearly do C30 and C.25 agree with the times in Class I., though 

 still not exactly. I then, with varying velocities from twenty 

 miles to thirty-five miles per minute, attempted to find some 

 small area (or comparatively small area) a simultaneous shock 

 from which would reach the five places in Class I. at the several 

 times observed. With a velocity of about twenty-six miles 

 per minute we can get such an area, marked EE' on the map. 

 The degree of agreement with the data may be tested by the 

 time at the origin, as calculated from the different places. 

 This time should, of course, be the same from whatever place 

 we calculate it. We get the same time — 2 hours 35 minutes 

 a.m. — from each of the five places in Class I. 



The places in Class II. give this time as follows : St. 

 Mary's, 2.38; Glenora, 2.86-4; Eagle Hawk Neck, 2.35-8; 

 Fingal, 2.37-9; Branxholm, 2.34-7; Campbelltown, 2.34-5; 

 Sorrento, 2.32-3 ; Wilson's Promontory, 2.33-8. The average 

 or arithmetical mean of these is 2 hours 35.4 minutes a.m., 

 which certainly does not contradict the evidence of the best 

 times. 



The epicentrum I therefore take to have included the whole 

 or part of the shaded strip EE', and not to have extended nearer 

 to any of the places of observation than EE'. How far it may 

 have extended to the south-east it is, of course, impossible to 

 say, as no observations were made on that side — probably not 

 very far. EE' is about forty-eight miles long and four miles 

 wide in the widest part. It lies between 153° 56' and 154° 36' 

 east longitude, and between 41° 13' and 40° 46' south latitude. 

 E is 353 miles from Launceston and 365 from Hobart. 



V35 is the position 1 have found for the epicentrum of a 

 previous well-marked earthquake — that of the 13th May, 

 1885. V35 is only seven miles from the boundary of EE', and 

 the two results seem thus to confirm one another in a remark- 

 able manner. The confirmation is all the greater as the area 

 over which the two earthquakes were felt was practically the 

 same. 



S, T is the position assigned for the same earthquake 

 (13th May, 1885) in the late Captain Shortt's map (as cor- 

 rected by himself), of which he kindly allowed me to take a 

 tracing. He seems afterwards, in a paper read before the 

 Eoyal Society of Tasmania, on the 16th November, 1885, to 

 have expressed an opinion that the origin lay rather further 

 to the north, and thus, I presume, not very far from V35, my 

 own result. 



