but had to catch hold of the grass or fern to avoid being rolled about on the ground.

The next one, in October, 1848, was evidently far more severely felt at Wellington than at Wanganui, as it did much damage in the infant city, and caused many people to leave it; while in Wanganui no injury was sustained of any consequence, and but little notice was taken of it.

That of the 23rd January, 1855, though severely felt in Wanganui, was evidently far worse in Wellington and its neighbourhood; and the same has evidently been the case in at least two shocks which have lately occurred, and have injured brick buildings in Wellington, while at Wanganui they scarcely attracted notice. A shock which occurred about fifteen years ago did much damage at Wanganui and Foxton, but apparently little or none in Wellington.

That of Wednesday last (8th December) has been of the very opposite character, as its effects have chiefly been felt at Wanganui. I had been awake for a few minutes when, at about 2.40 a.m., I heard a low rumbling sound, such as might proceed from a doctor's gig coming up the road on its way to the house of a sick person, the direction being from the south-west as usual. Doubt as to its character, however, was immediately set at rest by the commencement of strong undulatory and oscillatory movements, which rapidly increased in intensity, and in about a minute were of extreme violence. As I built my house myself, and my experience of the earthquake of 1855 had shown me the necessity of buildings being well put together, I had no fear of a collapse, and therefore contented myself with sitting up in bed to note what occurred. When the vibrations had lasted about a minute, and seemed slackening, the house seemed to give a sudden tremendous lurch or plunge, as if falling over towards the north-west, followed immediately by a similar and almost equally violent plunge towards the north-east. By the first of these it is said that a heavy piano in a house on St. John's Hill was sent almost across a room, whilst the whole of the books on a neighbour's book-shelves were thrown on the floor. In my own house a heavy wooden bedstead, without castors, was shifted about a foot from the wall at its head, and a chest of drawers about 4 ft. high, in another room, was thrown on its face. Downstairs the books on the shelves were all displaced, the upper and smaller ones to the extent of fully 3 in., though none were thrown down; articles of furniture were slightly moved, the piano being shifted a hand's breadth from the wall; and, of course, flowervases and similar articles were thrown down or broken. Similar, though slighter, lurches to south-east and south-west followed at intervals of about a second, it seeming evident that this

gyratory action arose from the earth settling down again to its normal level after being upheaved by the undulatory motion. After this the motion became extremely irregular, being a compound of gyratory and oscillatory as it died away. Nearly the whole of the chimneys in the houses around were thrown down, or so damaged that they will have to be rebuilt, though my own fortunately remained uninjured. It is estimated that at least a thousand chimneys in the town and suburbs will have to be rebuilt, and I think this is an underestimate rather than otherwise, while, of course, those similarly damaged in the country around will greatly increase the number. Those chimneys which were not thrown down are mostly broken horizontally, their upper portions being twisted round, in some cases at right angles to their original position. A brick wall, 80 ft. long by 10 ft. high, bonded with hoop-iron, which forms the north-east side of the Fruit-evaporating Works, is split horizontally from end to end about half-way up, the lower portion being forced outwards 2 in. or 3 in., while the upper portion inclines inwards to about the same extent. The end wall of the same building facing north-west was thrown bodily outwards and shattered to pieces, while the arch of the long evaporating-oven collapsed, the bricks falling on the travelling table beneath. Houses on brick or concrete foundations seem to be generally slightly shifted and twisted aside, and in some cases the foundations themselves are injured. Much glass was broken in windows of shops and houses, and this not by articles falling against it, but by the motion and straining of the buildings. The gyratory lurches evidently caused this, as the broken windows face in all directions. The town watermains are also evidently broken, though only one small break has yet been located. Of course, the damage to goods in the stores has been very great.

In a former paper, describing the earthquake of 1855, I mentioned that the whole foreshore of the river in front of the business portion of the town, from the quay roadway to low-water mark, appeared next morning like an ill-ploughed field, cracks having opened at distances of 1 ft. or 18 in. asunder, and the whole foreshore having evidently slipped outwards towards the deeper water. The whole of this foreshore, for about half a mile in length, has since been reclaimed, in the same manner as that at Wellington, and a wharf constructed along more than half this length, from the town bridge downwards; yet, notwithstanding this, it is evident that a similar outward slipping has occurred beneath the reclamation, which, when daylight appeared on Wednesday morning, was found to consist of a series of undulations, the difference of level between the highest and lowest points being estimated to amount to as much as 3 ft.; in fact, the appearance of the rails was de-

scribed as being like a switchback railway. The rails were also shifted laterally, in some parts to the extent of 2 ft. or more, and some of the fish-plates connecting them were broken. At its lower end, near the cattle wharf, the reclamation had subsided fully 18 in., while numerous cracks, one of them about 15 chains long by 5 in. or 6 in. wide, opposite the railway-station and Customhouse, had been opened. The wharf and stone facing of the reclamation had also evidently been forced outwards. On the roads in the vicinity of Wanganui a great many cracks have been formed, and in some places the outer portion of a side-cutting has slipped away, while in others water springs have broken out where roads ran along flats in valleys.

The whole of this damage was done by the one shock, the violent part of which only lasted about two minutes, though, slight tremors continued for several minutes afterwards.

No further shocks, or, at all events, not more than one very slight one, have since occurred; while in 1855 there were an immense number of such shocks, extending over many weeks.

The nurses at the Hospital and others say that a vivid flash of lightning immediately preceded the shock, and the same is also stated in a letter since received from Feilding.

One point which appears worthy of notice is the difference in the intensity of the shock in different places, this depending evidently on the nature of the soil. On clay soils the buildings are much damaged, the chimneys being everywhere ruined, and in many cases having fallen through the roof; and the same has happened on the low ground near the river, while houses standing on the sand-ridges have sustained no damage whatever. This evidently arises from the difficulty of transmitting a force through sand. The new hospital, a large brick building on a sandy formation, had only the plaster cracked in a few places and a small piece shaken down. Where the soil consisted of old swamp, which is now greatly reduced in thickness, and rests on a clay subsoil, the damage to buildings is nearly as great as on the clay hills. The pumice-sand formation, which forms the upper stratum in the Wanganui Valley, to a depth of about 10 ft., is of so coherent a nature that a face of it will stand when not only vertical, but even overhanging considerably. Thus vibrations are transmitted through it almost as well as through hard clay, as is evident when vehicles pass along the road, causing tremors to a considerable distance. Thus the houses all up the river-side were much damaged, and much injury is done to the contents.

I have thought these particulars worth notice, as the difference in the intensity of the shock being dependent upon

The general direction of these waves, however, shows clearly that the undulatory movement came from the south west. In fact, with a single exception, every shock which has been felt in Wanganui since November, 1851, has come from that direction, even that which originated near the Hanmer Plain. The single exception I observed at the time came from farther west than usual, and I learnt a day or two afterwards that it had done much damage at Nelson, and subsequently that it had originated some distance south-west of that city.

Had the shock of the 8th December come from the south-east the waves on the reclaimed land would have been in the opposite direction, and the general level of the rails would not have been appreciably altered. The shock, too, in that case, should have been more severely felt at Turakina, Marton, Birmingham, Ashurst, Woodville, &c.; while, as a matter of fact, no chimneys seem to have been shaken down beyond the Wangaehu Valley. In the same way, in its onward progress it should have destroyed the chimneys at Waitotara, Waverley, &c.; but it has not done so. The shock, in fact, may be said to have followed generally the direction of the Wanganui Valley, its violence not extending many miles on either side. The lurching motion which followed seemed clearly to come from the south-east, as the articles of furniture moved were so towards the north-west, which was also the direction in which chimneys generally seem to have fallen, and in which the end wall of the fruit-evaporating building was thrown out.

At the same time, I am unable to feel certain whether these things arose from the ground being suddenly canted towards the north-west, or whether it was, as it were, suddenly pulled beneath us towards the south-east. All that I can be perfectly certain of is that, as I sat up, facing north-west, I was first thrown forward, then to the right, then backward, and lastly to the left, with violent jerks, after which the motion, though less violent, seemed to go all ways in turn. The cracks on the reclaimed land were also, all of them, in the direction of its length, showing that the cause which produced them operated transversely to the undulatory movement.

The principal crack, about a quarter of a mile in length, was along the junction of the reclamation with the old riverbank, and seems to me to have been caused as follows: The undulatory movement had weakened the cohesion of the reclamation with the old foreshore underlying it, which it would do the more easily because, no doubt, the thin layer of mud between the two has always been kept wet and slippery by the tidal water. Thus, when the great lurch to the north-west occurred, the bank and old foreshore moved in that direction;

but the vis inertiœ of the reclamation, and of the railway-station and rolling-stock upon it, coupled with the difficulty of transmitting force through the sand of which the reclamation is formed, caused them to lag behind, as it were, and so produced the fracture. Beyond the upper or north-east end of this crack the junction passes under large mercantile stores and the abutment of the town bridge, and these seem to have held the surface together and prevented the crack extending any farther. At this part, too, the old river-bank became so low as to be scarcely discernible, while along the line of the crack it was from 4 ft. to 5 ft. high. The cracks farther towards the river seem all to have been between the railway-lines, and not under them, indicating that, though the increased depth of the reclamation outwards caused further fissures to form, from the same cause as the main one, the sleepers of the rails held the ground together underneath them.

It has occurred to me that possibly it was only this transverse movement that was felt in Wellington, the undulations coming in this direction. What I regard as the principal damage in Wanganui is that to the water-mains, which, so far as I can judge, must be leaking to a very great extent at their socket-joints, as since the earthquake the water-pressure is only about one-third of what it was previously. Thus far there have been no subsequent shocks.

A neighbour told me to-day of the most curious effect of the earthquake of which I have yet heard. A stream called the Tauraroa flows into the Wanganui River from the northward about nine miles above the town. The stream runs in a little gully some 30 ft. or 40 ft. deep, and perhaps a couple of chains in width. On the east of this there is a flat from 10 to 15 chains wide, which forms the general level of the valley; and east of this again there is a hill-face of over 400 ft. high, rising up to the table-land, known as Strafford's Flat. The flat in the valley has been for many years in grass, but I learn that since the earthquake 2 or 3 acres of it, half a mile or more from the river, appear as if they had been shot violently upward into the air to some height, and fallen back in fragments, as large lumps of papa, many of them several feet in diameter, are scattered about in all directions, and the grass has entirely disappeared from that area. I suggested to my informant that possibly the damage might have been caused by a large slip of the hill-face, but he said that the face, which is covered with light bush, was unaltered, and that the damage did not extend to the foot of it. In fact, he said he was perfectly confident that the effect could only have been produced by an explosive force acting from below.

During the earthquake of 1855 sand and water were thrown up through cracks in the ground, and were scattered

on the surface to a width of many feet, and to a depth of some inches, but there were no fissures on that occasion through which lumps of papa such as described could have been projected, and, in fact, were on alluvial flats. The place would be well worth examining, and I will endeavour to get more information about it.

Since I last wrote I have been able to gather the following particulars, which seem worth recording. First, as regards the direction, Mr. G. F. Allen, formerly of the Government survey staff, and now a settler in the Upper Wangaehu Valley, informs me that directly the shock occurred he lighted a candle, and went to see what damage, if any, had been done in his house. On entering his dining-room he found that a lamp, suspended from the ceiling, was still swinging steadily to and fro. He therefore laid a long straight-edge on the table immediately beneath the lamp, and exactly in the direction in which it was vibrating. When daylight returned he took the bearing of this straight-edge, and found it to be as nearly as possible south-south-west to north-north-east, the shock having come from the former direction.

The shock was severely felt over a much larger area than I had first supposed, several chimneys having been shaken down in the Upper Wangaehu Valley, the farthest of which was at least fifty miles north-east of Wanganui. Several houses in the Paraekaretu district, between the Turakina River and Hunterville, and fully twenty miles east of Wanganui, also lost their chimneys. In this locality, too, one house which stands on sandy ground escaped injury, while those all around were thus damaged. Chimneys were shaken down at Waverley, twenty-five miles west of Wanganui.

In my first paper I mentioned how the upper portions of chimneys were twisted aside, but I had at first some difficulty in ascertaining the direction in which the twisting occurred. One person who had been engaged taking down several chimneys thus damaged said at first, in reply to my question, that they were twisted all manner of ways, but on my pointing out to him that the force which caused the twisting must have acted in all cases in the same direction he took more notice, and subsequently informed me that the twisting in every case was from left to right, the opposite of the sun's apparent motion, and others whom I induced to take similar notice all said the same. As the twisting evidently arises from the vis inertiœ of the upper part of the chimney preventing its accompanying the lower portion in its motion, it is evident that the gyratory movement which caused the twist must have been in the opposite direction. The lurching motion I believe to be

really a gyratory one, its apparent angular motion being caused by that of the walls of buildings.

I have now experienced seven severe earthquake shocks at intervals of about seven years, and in every case the undulatory movement has been followed by the plunging gyratory one. Hence it is that I have come to the conclusion that the former movement upheaves the ground, and that the latter occurs during subsidence. When the plug is removed from the bottom of a basin or bath gyration is immediately set up during the descent of the water, and the same phenomenon may be observed in the sand running down from an hour-glass.

I have thought a good deal on the question as to whether this motion is really in its apparent direction or the reverse, and have come to the conclusion that the latter is actually the case—e.g., when the first violent lurch made it appear that the house was falling over towards the north-west I believe that what really occurred was that the ground was moved suddenly and violently towards the south-east. To explain my meaning try the following experiment: Lay a sheet of cardboard on a table, and on it place some object of which the height considerably exceeds the base. Then draw the cardboard suddenly towards you, and the object standing on it will fall in the opposite direction, just as if the end of the cardboard furthest from you had been depressed, or the nearer one uplifted. It appears to me that a mistake may thus occur as to the actual direction from which a shock proceeds, and that possibly even a seismograph may thus give a wrong indication. I have never seen an instrument of this kind, but from a description of one which I read some years ago it appears to me that in this way the apparently strange fact of the earthquake having seemed to come to Wellington from a different point from that from which it came to us may be accounted for, and the point seems to me worthy of consideration.

In my last paper I mentioned that a remarkable disturbance in the Tauraroa Valley had been reported to me, and subsequent information led me to believe that it was far more extensive than had been represented. On my mentioning it to Mr. Allen he took the trouble to visit the place, in company with Mr. Charles Smith, a member of our society, to whom the land belongs. I find that my first impression, that a landslip on a very large scale had occurred, was the correct one. The high table-topped ridge called Mount Trafford, which rises on the north-east side of the Tauraroa to a height of fully 400 ft. above the valley, has till now always been supposed to consist entirely of papa. This, however, is not the case; its lower portion is of soft sandstone, a perpendicular, or nearly perpendicular, face of which, fully 50 ft. in extreme

height and more than a quarter of a mile in length, is now exposed.

The existence of this sandstone formation has been hithertounknown, through its being overlaid by papa, and its face being hidden behind the-immense mass of debris which during countless ages had slipped down from above and formed the lower and flatter portion of the hill-face. This sandstone face is deeply scratched or furrowed by the substances—no doubt tree-roots—which have descended along it. In front of the face there is now a pool which Mr. Allen estimates as about 25 chains long by 50 yards wide, and 2ft. to 3ft. deep, from the northern end of which a strong stream flows into the Tauraroa. Outside of the pool there is a high ridge fully 30ft. in height, and outside of this again two or three smaller ridges, evidently caused-by the crumpling of the soil as it slipped. Beyond this again the soil is upheaved for some distance in a most irregular manner, and thence to the edge of the gully in which the Tauraroa flows the flat presents the appearance of having been ploughed into large furrows by a gigantic plough, many of the furrows being turned completely over. Mr. Allen estimates the whole disturbed area as containing certainly not less than 25 acres. The conclusion to which he and Mr. Smith came, after carefully examining the whole, was that the spring rains must have caused a large quantity of water or saturated earth to accumulate beneath the foot of the hill-face in front of the sandstone. This has doubtless always been the case, as Mr. Smith stated that there had always been a number of soakages all along the hill-foot at the back of the flat, by which the water escaped gradually during dry weather. The earthquake, however, set the whole of this water or saturated earth in motion, and thus caused the whole of the hill-foot for the length above stated to slide outwards to the width of the present pool, crumpling up the soil before it in its progress. Mr. Allen informed me that some large trees on the slipped earth are still standing erect, whilst the majority are thrown down, and many turned upside down. Mr. Allen also says that all along the valley there are traces of similar disturbances in the past, though none on so large a scale as the present one. In consequence of Messrs. Smith and Allen's visit to the spot, mention has been made of the disturbance in a local paper, and photographs have been taken, prints from which are announced to appear on Friday next. The newspaper paragraph speaks as if the scene of the disturbance had been the focus of the earthquake, and mentions sulphurous fumes as rising from the ground. The above description, however, as given to me by Mr. Allen, is unquestionably the correct one.