April 23, 1908] 



NA TURE 



595 



paper and driven by elockwork, was brought up lo within 

 one-eighth of an inch from these holes. A rim on the 

 bottom part of the drum had a clearance given to it by 

 cutting a horizontal slit in the zinc plate beneath the holes. 

 Neither the drum, the paper, nor the rim touched the. zinc 

 plate or the chalk. The rate of movement of the paper 

 was 90 mm. per day. A small electric lamp moved about 

 outside the box produced no effect upon the paper inside. 

 A self-recording thermometer and a hygrometer showed 

 that the temperature and the moisture in the chamber were 

 practically constant. A similar piece of apparatus was 

 installed at a depth of i6o feet in the King Edward Mine, 

 Camborne, Cornwall. These experiments were commenced 

 at Pan Chalk Pit in February, 1903, and were continued 

 for four months. They were taken up again in the middle 

 of August, 1906, and lasted eight months. A sheet oi 

 paper on development was frequently quite clear,- but at 

 times it w-as partly or entirely marked with dark bands, 

 black lines, round black spots, or semi-circular spots along 

 the lower edges. At Shide the dark bands have not been 

 numerous, but they occurred on nearly all the sheets from 

 Camborne. In certain cases we appear to have three bands, 

 the positions of which apparently coincide with the three 

 holes in the zinc plate. In some of these bands there are 

 hard black lines broken along their length and made up 

 of black spots. 



The black spots vary in diameter from a fraction of a 

 millimetre to 8 millimetres. In the centres of some of 

 these there is a small white or brownish spot. As pointed 

 out by Mr. W. H. Bullock, of Newport, these closely 

 resemble spots which can be produced on bromide paper 

 by a tiny electric spark. During a week we may have 

 either no spots, one spot, or a hundred spots. The semi- 

 circular spots, which I have called singeings, are found 

 on the lower edge of the paper where the brass cylinder 

 joins the aluminium rim. There may be two or three of 

 these per week, whilst at other times they occur at intervals 

 of about half an hour. As only ten black spots occurred 

 at the time of large earthquakes, we can only regard 

 these as coincidences. Neither dark bands, spots, nor 

 singeings appear to be connected, beyond what I have 

 mentioned, with any particular meteorological conditions. 

 Neither is there any reason for supposing that these effects 

 are due to radio-activity. If a piece of bromide paper is 

 sealed up in a black envelope, and another piece is placed 

 in a black envelope which has a thin glass window, and 

 these are laid on a surface of chalk, the glass window 

 touching the same, say, for a period of several days, it 

 was found after development that one piece of paper sliowed 

 the image of the window, whilst the other had only stains, 

 which might be attributed to dampness. With the object 

 of determining whether micro-organisms played any part 

 in the phenomena observed, my friend Dr. R. C. Brown, 

 of Parkhurst, has made cultures from scrapings from the 

 surface of the chalk before which my cylinder was exposed. 

 Cultures were also made from scrapings taken from the 

 open chalk. Micro-organisms were found in both. These 

 have been exposed to a moving photographic surface 

 similar to that used in the pit, but they gave no evidence 

 of luminosity. The conclusion for the present is that the 

 luminosity occasionally seen at Pan Pit may result from 

 a very feeble brush or glow-like electrical discharge. If 

 this be the case, it would also account for the bands on 

 the photographic paper, the other markings being due to 

 minute sparks. Moreover, if this is so, and we assume 

 that silent electrical adjustments have a real existence, it 

 is difficult to escape the conclusion that these must have 

 an effect on what we call " climate," and hence upon 

 everything that lives upon the surface of the globe. We 

 have many instances of places only separated by a few 

 miles, as, for example, Newport and Sandown in the Isle 

 of Wight, or Bournemouth and Swanage, the climates of 

 which are said to be very different. The thermometer, 

 barometer, and hygrometer do not explain these differ- 

 ences ; the only apparent difference between such places 

 appears to be one of soil and the moisture in the same. 

 Inasmuch as we find great differences in the emanations 

 from granite, clavslate, and chalk, it would seem extremely 

 probable that we should find differences in the relative 

 electrical conditions of different soils. 



To dftermine whetlvr earthquakes are increasing or 



decreasing, it is not only necessary to turn over the pages 

 of many histories, but also to consult the geologist. Jules 

 Verne might perhaps have dipped deeper into time than 

 a geologist or physicist, and drawn pictures of the re- 

 actionary effect which might accompany the collision of one 

 world w'ith another, bombardments of great meteorites, a 

 click that announced the birth of our moon, the sudden 

 yieldings of a primitive crust covering an ocean of molten 

 rock, and of many other things that float through the 

 brains of those who entertain us with the results of their 

 imaginations. The greater number of earthquakes, and 

 certainly all that are large, originate from the formation 

 or extension of faults. These operations have been most 

 marked when secular movement amongst rock masses is 

 in progress, as, for example, during the growth of moun- 

 tains. Should this be in operation near large bodies of 

 waters, volcanoes and earthquakes are found in the same 

 region. If, therefore, we wish to know when earthquake 

 frequency and intensity was at a maximum, we turn to 

 those periods in geological history when mountain ranges 

 were built, when volcanic activity was pronounced, and 

 when great faults were made. The first of these periods 

 would be coincident with the creation of the Urals, the 

 Grampians, and other ancient mountain ranges. This took 

 place in Palaeozoic times. Another period of mountain 

 formation was in early Tertiary times, when the Himalayas 

 and the Alps were slowly, but intermittently, brought into 

 existence. In both these periods volcanic activity was pro- 

 nounced, and beds of coal were formed. When the crust 

 of the earth was crumbling, mountains grew spasmodically, 

 faults gave rise to earthquakes, volcanic forces found their 

 vents, and conditions existed which gave rise to the 

 accumulation of materials to form coal. 



In quite recent times, many large faults have been 

 created at the time of earthquakes. In 1891 the Mino- 

 Owori fault was created in central Japan, 10,000 people 

 lost their lives, and 128,000 buildings were destroyed. On 

 April 18, 1906, San Francisco and other towns were ruined 

 by movements along a fault which can be traced for a 

 distance of 200 miles. One estimate suggests that it may 

 be 400 miles in length. The largest fault which has been 

 created in extremelv recent geological times seems to be 

 the Great Rift Valley of Central Africa. We are told that 

 it commences in the south near Lake Nyassa, passes north- 

 ward through Tanganyika, the great lakes of Central 

 Africa, branches north-eastward towards Lake Rudolph, 

 up the Red Sea, through Akaba to the Jordan Valley, a 

 distance of 4000 miles. In certain districts it shows itself 

 as a strip of country let down between two parallel frac- 

 tures. It has been compared to the cracks w-hich can be 

 seen in the moon. If we accept this as a reality, we have 

 only to imagine this Great Rift fault to be .extended as 

 regards its length and breadth, and we have a trough in 

 many respects similar to that which holds, not thirty lakes, 

 but the waters of the Atlantic. If we look at the Atlantic, 

 either as shown on a Mercator's chart or on a globe, we 

 notice the complementary resemblances between the con- 

 tours of the old world and the new. Then, if we draw 

 a line down the submerged backbone of this ocean, we see 

 that this is the reflection of the European and Nortli 

 African western coast line (Fig. 2). Next, if these old- 

 world contours are pushed westwards towards this median 

 line, while the contours of the two Americas are pushed 

 eastwards, we find that one approximately fits in with the 

 other. The fit becomes more marked if we bring together 

 the submerged edges of continental shelves or lines re- 

 presenting the general direction of the opposing coast lines. 

 Another point not to be overlooked is that the rock forma- 

 lions on the west side of the Atlantic are very similar to 

 those in the same latitude on the eastern side. _ It is as 

 if we had a street with the shops on one side of it exactly 

 similar to those on the other side. In northern Spits- 

 bergen, and again in Greenland, w^e find a large develop- 

 ment of crvstalline and Pala;ozoic rocks, and these con- 

 tinue southwards through Labrador, Newfoundland, Maine, 

 and then through the Alleghanies. They again appear 

 in Brazil as far south as Monte Video. On the eastern 

 frontier of the Atlantic, from Scandinavia through Scot- 

 land and Ireland, Wales, western France, and western 

 -Africa as far as Cape Town, we see a replica of the two 

 .Americas. The .Atlantic is a canal, the opposing bank:^ 



NO. 2C0S, VOL 



