May 8, 1884] 



NA TURE 



3i 



This letter has already run to great length, but in conclusion I 

 should like to add a few words anent the wooden ornaments 

 already referred to. They are usually turned in a lathe, and in 

 shape are not unlike the ninepins of our childhood, but the knob at 

 the top is originally larger in proportion, and continued upwards 

 into a tenon ; the knob is then carved away so as to leave two 

 interlocking loops, and the tenon is fitted into the weather board. 

 At the corners of the roof there are often pendent disks of wood 

 fringed with these ninepins, so as to form a sort of wooden 

 tassel. These would answer well for a rude copy of bells which 

 similarly fringe the roofs of the Chinese pagodas, and it is 

 possible that there is a direct connection between the two, but in 

 any case their association with a concave roof is at least a 

 remarkable coincidence. B. D. Oldham 



Camp Matil in the Himalayas, April 9 



The Recent Earthquake 



SINCE the earthquake of Lisbon in 1755 troubled the waters 

 of the fish-pond, called Peerless Pool, in the London City Road, 

 it has been a well-known fact that earth-waves had a direct 

 influence in producing an alteration in the level of waters inland, 

 as well as in producing tidal waves sweeping the coasts. The 

 earthquake of Tuesday, April 22, has produced a marked, and, 

 so far, permanent, change in the level of underground waters in 

 the district most affected by the shock, but how far this influence 

 extended there is not yet evidence to show, for, judging by past 

 experience, it may probably prove that springs have increased in 

 volume and the underground water-levels have been raised over 

 the whole area affected by the recent shock, which includes the 

 district lying between Broadstairs and Bristol, 165 miles from 

 east to west, and hem Spilsby to Ryde, 170 miles from north to 

 south, and possibly beyond it. It will be of especial interest to 

 know whether the Wealden area, which, as Mr. Topley has 

 pointed out, was free from the more direct influence of the shock, 

 experienced any rise in its underground waters. 



At Colchester the water supply is derived from a deep artesian 

 well in the chalk, the supply from which has slightly lessened 

 during the past few weeks, necessitating the lengthening of the 

 suction pipes ; and the necessity of still further lengthening them 

 was under discussion, when the Water Committee were agreeably 

 surprised to find that the earth-wave of the 22nd had caused an in- 

 creased flow of water, and a rise in the water-level of 7 feet, which 

 has so far been maintained. 



Earthquakes were described by Mallet " as the transit 

 of a wave of elastic compression." This motion at Langen- 

 hoe produced fissures in the gravel walks of the vicar's 

 garden, and at West Mersea opened a fissure a rod in length, 

 which for a short time took off the springs which supply the vil- 

 lage with very pure water, and when, after an interval, the pools 

 in which the water accumulates were again full, it was found to 

 be red and thick, and in some of them to be strongly mixed 

 with chalk. 



At Bocking the height of the water in Messrs. Courtauld and 

 Co.'s well has been taken weekly for some years ; the surface of 

 the well is I37'07 feet above the mean sea-level, and the heights 

 given represent the number of inches the water rises above the 

 surface ; the results are very remarkable, the highest previous 

 reading being on Easter Monday, 1S83, when it was 19 inches. 



The following is the weekly record of the level of water in 

 Messrs. S. Courtauld and Co.'s well, Bocking, Braintree, Essex. 

 The observations are made at 6 a.m. on Monday mornings ; no 

 water is drawn from the well on Sunday. 



Corresponding period 1883 



Inches 

 13 



144 

 16 



15 



The readings being weekly, and the earth-wave occurring the day 

 after the record was taken, unfortunately a week elapsed before 

 the remarkable rise was ascertained ; after that the readings were 

 taken daily, showing a continued steady rise in level. 



These facts tend to show that the recent earth-wave has caused 

 the fissures to open, and to permit a freer circulation of water, 

 and that consequently the "cone of exhaustion" has been filled 

 up with water ; and that the only example of this effect so far 

 received should be from chalky districts is not surprising when it 

 is remembered, as Prof. Ansted pointed out, that, though the 

 chalk absorbs water freely, it parts with it slowly, the water 

 derived from chalk-wells being due more to water travelling in 

 the joints and fissures than to the water stored in the chalk itself. 

 It would appear probable that when the increased volume of 

 water now running off, through the enlarging of the sectional 

 area of the fissures, is again lowered by 'pumping, the old 

 artesian gradients will be resumed, and that the present increase 

 will be only temporary. 



As Secretary of the Underground Water Committee of the 

 British Association, I shall be glad to receive any further infor- 

 mation on these phenomena. C. E. De Rance 



Museum, Jermyn Street, S.W. 



From recent observations I have concluded that the seismic 

 vertical was at or near Dr. Green's house, close to the Strood 

 or Causeway which connects the mainland of Essex with 

 Mersea Island. The house was built in i860, and is therefore 

 new. I may here observe that (as I hinted before in former 

 letters) the modern, cheaply-built cottages were not so much 

 affected as the more ancient ones. The chimneys, walls, &c, 

 of the latter were invariably destroyed, damaged, or cracked — 

 the former seldom so. I was much surprised at this. The first 

 thought naturally was that these "jerry-built" houses would be 

 shaken down like a pack of cards. Is it that their very looseness 

 of structure is in their favour, as compared with the stronger-built 

 cottages of two and three hundred years ago ? I have somewhere 

 seen that in earthquake-visited centres the houses most secured 

 from destruction are the loosely-built, low edifices. One can speak 

 plainly on this matter, as no premium is required to encourage 

 the development of "jerry-building." 



Dr. Green's house is literally split and cracked in all direc- 

 tions, and the splits and cracks are the most vertical of any to 

 be seen. The entire building was twisted on its foundations. 

 At the south-west corner this is visible to the amount of about 

 one inch and a half. Dr. Green informed me he was lifted up, 

 as if from behind, and shot violently forward. 



A friend of mine remarks (and I noticed the same fact in my 

 note-book, but omitted inclosing it in my last communication) 

 that the railway cutting at Wivenhoe appears to have broken the 

 continuity of the undulations, for the houses contiguous to it are 

 comparatively uninjured. 



A noteworthy fact in connection with the recent earthquake, 

 to which I can personally testify, and which appears to be the 

 general experience of all the most trustworthy observers I have 

 come across, is that the sounds or noises preceded the oscilla- 

 tions for an appreciable period of time. Mallet's experiments 

 showed that the shock of an explosion travelled through wet 

 sand at the rate of 951 feet per second. In Ipswich we are 

 situated chiefly on drift sands and London Clay, and allowing 

 that the earthquake shocks travelled through these strata at a 

 more rapid rate, it is not likely to have been much more rapid. 

 As sound travels at the rate of 11 18 feet per second, it is very 

 probable that the noise accompanying the earth-movements pre- 

 ceded the oscillations 



Mr. Wilkins, the well-known yacm-buiiner at Wivenhoe, tells 

 me he was standing at the time the earthquake occurred in the 

 yard, and his first impression was that a new yacht he was 

 looking at was heeling over, and he called out so to his workmen 

 in the shop close by. Then followed the crash of the tall 

 chimney and the rending of the walls. The workshop has an 

 upper floor, with windows on each side, and, as he stood in the 

 yard, Mr. Wilkins says the oscillatory waves were such that he 

 was enabled to look right through these windows, so as to see 

 the falling chimneys of the buildings on the other side. He cal- 

 culates that there must have been a rise and fall of the ground of 

 2 feet 9 inches to have enabled him to do this. 



On Saturday, May 3, the members of the Ipswich Scientific 

 Society made an excursion to Langenhoe and Peldon, and Mr. 

 Henry Miller, C.E., the honorary secretary, kindly took the follow- 

 ing exact measurements of the rents seen in a building adjoining 

 Peldon Mill. There are two of them, succeeding each other at 

 a short distance, and they pass through the brickwork at an 

 angle of just 30°. At the gable end of this building there is 



