June 8, 1882] 



NA TURE 



125 



Another observer, writing from Pre-.tv.ich to the Manchester 

 Examiner and Times, describes it as having moved from S.S.E. 

 to N.N.W., passing a few degrees to the east of the 2enith, and 

 exploding and then vanishing at an angle (altitude) of 40° to 45°. 



At Tarporley it was visible for thirty seconds, moving from E. 

 to N.N.W. 



The same fireball was also seen in Cheshire. 



Stonyhurst Observatory, Whalley, May 31 S. J. Perry 



On May 16, about II p.m., I saw a meteor that was, I think, 

 the most terrific, as well as the grandest, I have ever happened 

 to see. I reached my house about ten minutes afterwards, and 

 at once wrote down, substantially, the folio 'ing unvarnished 

 account of the phenomenon. It may have been witnessed and 

 recorded by some one el-ewhere. If so, the observer may like 

 to compare my record of it with his own : — I was walking west- 

 ward, and I was about two miles south-west of Woodstock (as 

 the crow flies). Suddenly my attention was drawn upward by a 

 brilliant light. I then saw a meteor high up in the western sky, 

 and a little south of the Great Bear. It was descending at an 

 angle of 50°. lis speed was so moderate, that I got a good 

 observation of it. Its seeming size was, I think, quite half that 

 of the full moon. It appearance was such as I never saw 

 before : it struck me as being like a transparent lantern, or, 

 rather, pail, full of burning matter. Its base was a sharply- 

 defined broad cone. It looked as though let down from above 

 by an unseen string, rather than falling. It seemed to be very 

 near me. A nickering reddish flame rose, fitfully, straight up 

 from the horizontal surface of its yellow-hued fiery mass. It 

 vanished, without my seeing any scattering of sparks, when it 

 was about half way between the Pointers and the horizon. 



John Hoskyns-Ahrahali. 



Combe Vicarage, near Woodstock, May 27 



Earth-Tremors in Japan 



An article on earth-tremors, which appeared in the Times last 

 November, seems to have attracted considerable attention in Japan, 

 and a few facts respecting the work w hich has been attempted in the 

 investigation of microseismic disturbances in this country, may 

 possibly be of interest. In the Transactions of the Seisrnological 

 Society of Japan we have already had three communications on 

 this subject. Prof. H. M. Paul told us how, when searching 

 for a site for the United States Naval Observatory at Washington, 

 by watching the reflection of the image of a star in a vessel of 

 mercury with a telescope, he was easily enabled to detect earth- 

 tremors prcduced by a railway train at the distance of a mile. 



Major H. S. Palmer, R.E., of Ilong Kong, gave us an 

 account of how, by digging a trench large enough to contain 

 himself and his instruments when seeking fnr a station from 

 which to make observations on the Transit of Venus, he practi- 

 cally escaped from earih-tremors which emanated from a railway 

 line about 400 yards distant. As there are strong reasons fox 

 believing that many of the earthquakes which are felt in 'i edo 

 are produced by the faulting of the rocks, it was natural to 

 assume that before the actual breakage took place there might be 

 a crackling or gradual giving way which would be indicated to 

 us by preceding earth-tremors. 



In order to determine the presence of these earth- tremors, at 

 the end of 1879 I commenced a series of experiments with a 

 variety of apparatus, amongst which were microphones and sets 

 of pendulum apparatus, very similar in general arrangement, 

 but, unfortunately, not in refinement of construction, to the 

 arrangements now being used in the Cavendish Laboratory. 



The microphones were screwed on to the heads of stakes 

 driven in the ground, at the bottom of boxed-in pits. In order 

 to be certain that the records which these microphones gave 

 were not due to local actions, such as birds or insects, two dis- 

 tinct sets of apparatus were used, one being in the middle of the 

 lawn in the front of my house, and the other in a pit at the back 

 of the house. The sensitiveness of these may be learnt from 

 the fact that if a small pebble was dropped on the grass within 

 six feet of the pit, a distinct sound w as heard in the telephone, 

 and a swing produced in the needle of the galvanometer placed 

 in connection with these microphones. A person running or 

 walking in the neighbourhood of the pits, had each of his steps 

 so definitely recorded, that a Japanese neighbour, Mr. Masato, 

 who assisted me in the experiments, caused the swinging needle 

 of his galvanometer to close an electric circuit and ring a bell, 



which, it is needless to say, would alarm a household. In this 

 contrivance we have a hint as to how earth- tremors may be 

 employed as thief-detectors. 



The pendulum apparatus, one of which consisted of a 20 lb. 

 bob of lead at the end of 20 feet of pianoforte wire provided 

 with small galvanometer mirrors, and bifilar suspensions were 

 also used in pairs. 'With this apparatus a motion of the bob 

 relatively to the earth was magnified icco times, that is to say, 

 if the spot of light which was reflected from the mirror moved a 

 distance equal to the thickness of a sixpence, this indicated there 

 had been a relative motion of the bob to the extent of I oooth 

 part of that amount. 



The great evil which every one has to contend with in Japan 

 when working with delicate apparatus are the actual earthquakes, 

 which stop or alter the rate of ordinary clocks. 



Another evil which had to be contended with was the wind, 

 which shook the house in w hich my pendulums were supported, 

 and I imagine the ground by the motion of some neighbouring 

 trees. A shower of rain also was not without its effects upon 

 the microphones. After many months of tiresome observation, 

 and eliminating all motions w hich by any possibility have been 

 produced by local influence, the general result obtained was that 

 there were movements to be detected every day and sometimes 

 many times per day. 



Although these observations, which I found required more 

 attention than a private observer was enabled to give to them, 

 have been discontinued, I sincerely hope they may be again 

 taken up. My reason for this is that in a country like Japan, 

 where earthquakes are in some part or other phenomena of 

 everyday occurrence, we have excellent opportunities of deter- 

 mining whether any c< nnection exists between earthquakes and 

 earth-tremors. The idea that earth-tremors may be the fore- 

 runners of earthquakes is by no means novel, and that earth- 

 tremors aciually exi-t was demonstrated some years ago in 

 Florence by Timoleo Bartelli, who made microscopic observa- 

 tions of the pointer of a pendulum, which, to free fr. m local 

 surface action, he suspended in a cell. The localities which I 

 should recommend for the observations of earth-tremors would 

 be as near as possible to some earthquake centre. The localisa- 

 tion of these centres, however, is a matter of some difficulty. 

 The difficulty arises from the fact \ba\gocd time observations on 

 earthquakes have, so far as I am aware, never yet been obtained ; 

 and farther, although we are able w ith our seismographs to w rite 

 down the direction in which the earthquakes shake us backwards 

 and forwards, these directions by no means always tell us the 

 direction in which an earthquake came, an east and west motion 

 having sometimes been proved to have travelled broadside on up 

 from the south. 



A grsat assistance to tbe interpretation of the various records 

 which an earthquake gives us on our seismographs is what I may 

 call a barricade of post-cards. At the pre-ent moment Vedo is 

 barricaded, all the towns around for a distance of one hundred 

 miles being provided with post-cards. Every one of them is 

 posted with a statement of the shocks which have been felt. 



For the monhs of October and November it was found from 

 the records of the post cards that nearly all the shocks came 

 from the north and passed Vedo to the south-west. When 

 coming in contact with a high range of mountains, they were 

 suddenly stopped, as was inferred from the fact that the towns 

 beyond this range did not perceive that an earthquake had 

 occurred- This fact having been obtained, the barricade of 

 post-cards has been extended to towns lying -tiil farther north. 

 The result of this has been that several earthquake origins have, 

 so to speak, been surrounded or coralled, whilst others have been 

 traced as far as the seashore. For the latter shocks earthquake 

 hunting with post-cards has had to cease, and we have solely to 

 rely upon our instruments. Having obtained our earthquake 

 centres, at one or more of these our tremor instruments might be 

 erected, and it would soon be known whether an observation of 

 earth-tremors would tell us about the coming of an earthquake 

 as the cracklings of a bending do about its approaching breakage. 

 To render these experiments more complete, and to determine 

 the existence of a terrain tide, a gravitimeter might be e-ta- 

 blished. I mention this because if terrain tides exist, and they 

 are sufficiently great from a geological point of view, it would 

 seem that they might be more pronounced and therefore easier 

 to measure in a country like Japan, resting in a heated and 

 perhaps plastic bed, than in a country like England, where vol- 

 canic activity has so long ceased, and the rocks are, compara- 

 tively speaking, (cold and rigid, if an instrument sufficiently 



