578 Transactions. — Miscellaneous. 



Hutt, Foxton, and Wellington appears to be required on ac- 

 count of the time being a multiple of five minutes, as the ob- 

 servers at those stations have been in the habit of giving the 

 time to the nearest minute — in the case of Wellington, to the 

 nearest half-minute. At three places the shock is said to have 

 been preceded by rumbling ; at Picton " the house shook and 

 the windows rattled;" at Foxton " crockery rattled about con- 

 siderably;" and at Masterton the Postmaster was awakened 

 by the shock. An important detail is mentioned by the Foxton 

 observer — namely, that the shock he records was "preceded 

 by a slight premonitory shake," how long before he does not 

 state. This seems to show that there were two shocks, and I 

 think we are justified in assuming that the times at the Upper 

 Hutt and Wellington, as well as that of Foxton, belong to the 

 second shock. 



The simultaneous arrival of the vibrations at Blenheim, 

 Masterton, and Martou gives us for the epicentrum a point in 

 Cook Strait sixty-five miles from each of these places (forty- 

 four miles N. 24° W. from Wellington). The inclusioii of 

 Picton and Woodville with them gives us almost exactly the 

 same spot. If we take in Featherston also, we must suppose 

 an epicentrum five miles further to the south-east.* 



For the second shock the time — 10.55 — at the Upper Hutt, 

 Foxton, and Wellington implies -an epicentrum two miles 

 north-west of the first epicentrum. A circle of three miles 

 radius would include all the epicentra found, and if we reject 

 Featherston a circle of one mile radius would satisfy all the 

 data. The velocity of propagation is eighteen miles per 

 minute. 



The agreement of the observations is remarkable, for with 

 the utmost allowance for probable errors the epicentric area 

 found is very small. The velocity must lie between fifteen 

 miles and a quarter per minute and eighteen miles per minute, 

 and the time at the origin between 10.48^ p.m. and 10.49i p.m. 

 Compared with time-observations those of direction are usually 

 of small value ; they may, however, be used cautiously for 

 testing our results. ■ In the present case it will be found that 

 (lines being drawn in the given directions, and at right-angles 

 thereto, so as to include cases of normal and transverse vibra- 

 tions) the direction of the epicentrum found agrees almost 

 exactly with Upper Hutt and Marton, and is in accordance 

 to the nearest half -quadrant (or within 22^") w^ith all the rest 

 except Blenheim, Masterton, and Picton, the errors of these 

 directions being 25°, 31°, and 27° respectively. 



We have thus as good a confirmation as we can expect of 



* If the clock at the last place was forty seconds slow the same epi- 

 centrum would be given as for the other places. 



