the shock of 2.30 a.m., 12th October, was followed by incessant booming like the fire of artillery in the distance, but some of the explosions seemed quite close at hand. A visitor thus describes them: “On Friday, the 12th October, at 2.25 a.m., I was awakened out of sleep by a most violent shock, or, rather, double shock, as there was a break of some two or three seconds in it. As soon as this had subsided these underground explosions began, and followed each other at intervals of, say, five seconds for some minutes, when they diminished in quantity but increased in strength, until every explosion made the house (a galvanized-iron one) quiver and rattle. This continued until 8 o'clock a.m., during which time we had seventeen shocks, five of which may be termed sharp.” I myself heard two booms on the 3rd November and three on the 9th November. Those of the 3rd November were at about twenty seconds' interval, and each lasted about five seconds. The sound was like that of a distant avalanche; they were not loud, and were not followed by any shock. Those on the 9th November were of quite a different character: they were short and sharp, like the explosion of a cannon at a distance. They were not followed by a shock, but I fancied that there was a slight shake simultaneous with the sound and quite as short. This, of course, would be an air-reverberation, and not an earth-wave. One of these booms was at 10.30 a.m., another at 3.14 p.m., and the third at 3.20 p.m. There was also another of a similar nature at about 2 a.m. the next morning. Mr. McKay mentions having heard noises of two different characters—one on the 7th October, which resembled the rumble of a distant avalanche, and was accompanied by a slight shock; the other, which was later on the same day, resembled a strong blasting-shot in a mine, and was not succeeded by a shock. Inquiries made on the ground lead me to think that these two kinds of sounds have been heard all through, and that each kind, when loud, was followed by a slight shock at about two seconds' interval.

On the 13th November there was a loud boom at 2.10 a.m. and another at 10.5 a.m. Both these were followed, at between one and two seconds' interval, by a sharp short shake, like the blow of a hammer, quite distinct in character from the earthquakes unaccompanied by a boom, one of which took place at 11 a.m. on the same day, and has already been mentioned as a swaying movement lasting for thirty seconds.

These sounds have been heard in the valleys of the Hope and the Edwards, and doubtfully at Cannibal Gorge, as well as on Hanmer Plains and the hills immediately surrounding them; but they were not heard at Culverden or Waikari on the south, nor at Tarndale on the north, nor at Reefton or Boatman's or Lyell on the west. At the Hanmer Plains it is

generally agreed that they came from various directions between west and north; and they appear to me to proceed from an elongated area some thirty miles in length, between the hot springs in the Hope and the hot springs in Cow Creek, or perhaps from the neighbourhood of these two localities only.

As a rule the hot springs at Hanmer showed no sympathetic action with the noises, the only exception being a sharp boom, like a cannon-shot, at about 11.15 a.m. on the 14th September, accompanied by a shock which appeared to be nearly vertical. On this occasion a small quantity of mud and water was thrown from one of the smaller springs only.

It is difficult to offer a satisfactory explanation of these noises: they have been heard with other earthquakes, but never explained. In our case it is evident that the main earthquake, and all those of the same character that followed it, were quite independent of the cause of the booms. This is shown by the fact that many shocks were not accompanied by any noises, although they were heavier than those following the booms, and also by the heavier shocks of the 1st September, 28th September, and 12th October being followed, not preceded, by noises for several days. On the other hand, as the booms were heard before the main earthquake, their origin must be independent of it; but, as they were far more frequent and much louder after the shocks, it is evident that to a large extent they were secondary effects of the earthquake.

Mr. Mallet suggests that the noises heard after the Cachar earthquakes of 1869 were due to grinding or crushing of rocks; but this explanation will hardly do for our case, because many of the earthquakes were not accompanied by noises, and the booms do not come from the direction of the epicentrum of the earthquakes. The sounds appear to me to be much more like explosions of steam than crushing of rock; and this seems to be the only other explanation. There is no direct evidence to show that they are connected in any way with the hot springs, but their geographical distribution strongly suggests it. Hot underground water undoubtedly exists in the district in which the sounds have been heard, and at a comparatively small depth this water may be above the boiling-point, but kept fluid by pressure. If this pressure were removed, part or the whole might flash into steam and produce an explosion which would cause a boom. An earthquake might first compress this water, and then, on the backward swing of the wave, the pressure would be relieved and explosions take place; or part of the heated water might be expelled by the shock, which would reduce the pressure on the rest. It seems useless to offer such speculations as these, and I should not have done so if it had not been suggested that these explosions