xxviii Proceedings, &c, for 1868. 



parts of the Australian coast. Sydney, Newcastle, New Zealand, 

 and the Chatham Islands were visited, and the wave was even felt 

 to a small extent so far as Guichen Bay and the Gulf of St. Vincent. 

 It was generally supposed that this was to be traced to some earth- 

 quake, and the first thing that suggested itself to him (Mr. Ellery) 

 was to reduce the different times as near as possible, so as to arrive 

 at one mean time. He had got the time at Sydney to a few seconds, 

 and pretty accurately at Newcastle, and also with some accuracy in 

 New Zealand, but beyond that he had no reliable data. It was on 

 the afternoon of the 15th August that the tidal wave was experienced 

 in Sydney, &c, and news had now come of the frightful earth- 

 quake at Chili and Peru, which was no doubt the cause of the tidal 

 disturbance in these waters. The wave was first noticed at Sydney 

 2 h. 29 min. on the morning of the 15th August (Melbourne mean 

 time), and the great wave occurred at about 24 min. past seven in 

 the morning. At Newcastle it was first noticed at 7 h. 2 min. in 

 the morning, and five hours afterwards occurred the greatest 

 disturbance. In New Zealand the first disturbance occurred at five 

 a.m., and the greatest wave was not noticed until a little after the hour 

 of noon. The earthquake was reported as having taken place in 

 Chili and Peru on the 13th August, but no hour was mentioned. 

 Assuming at a guess that it took place at an early hour in the 

 morning, say three o'clock, it made it the afternoon here. Between 

 this time and the occurrence of the tidal wave at Sydney, there was 

 an interval of thirty-two hours, and assuming the distance between 

 Callao and Sydney to be about 6,500 statute miles, or 5,700 

 geographical miles, it gave the velocity of the wave at about 200 

 miles an hour, a rapidity which to him seem scarcely conceivable. 

 The district in which this earthquake occurred was one in which 

 earthquakes were very prevalent and destructive. It was pretty 

 well understood now that the intensity of earthquakes decreased with 

 the distance from active volcanoes. The first earthquake of any 

 consequence which was fully described was that at Callao in 1747, 

 which was stated to have destroyed the city and all the inhabitants 

 save one. This last earthquake, of which the account has just 

 arrived, must have extended from 1° north to 22 z south, and perhaps 

 further. No account had been received from Valparaiso, but it was 

 possible that the earthquake had been destructive as far as that 

 rjlace. It had been pointed out that in the earthquakes on the 

 Chilian coast, these were only the secondary destroying influence — 

 it was the earthquake wave that destroyed life and property. The 

 destructive influence of this earthquake was no doubt felt further 

 south than 22°, for Iquique, where it was experienced very severely, 

 was as low as 21°. He visited that place some years ago, and he 

 recollected that it was near a very active volcano — not more than 

 fifteen miles off. These were some of the facts he had got together, 

 and he would leave it to the other members to discuss the question. 



