August 1, 1900.] 



KNOWLEDGE. 



109 



ILLUSTRATED MAGAZINE 



^iCiENCEJlTERATlliytART. 



Founded by RICHARD A. PROCTOR. 

 LONDON: AUGUST 1, 1900. 



CONTENTS. 



■ — » ) 



The Great Indian Earthquake of 1897. By Chahles 



Davison. sr.D., f.o.s. (Ilhs/rafeil) 

 The Evolution of Simple Societies. — IV. The Beginning 



of Agriculture. ll_v I'lvf. Alfbkh C. Haddon, m.a., 



SlMl.. F.K.S. 



Astronomy without a Telescope. — VII. Meteors: — 

 The Perseids. B_v K. Walter AIaundke f.r.a.s. ... 



The Total Solar Eclipse of 1900, May 28. By E. 

 Walter MArxDER, F.R.A.S. {Illustrated) 



The Corona of 1900. May 28 (S.W. Quadrant). (Plate) 

 Some Early Theories on Fermentation. — II. By W. 



Stanley Smith. rn.D. 

 British Ornithological Notes. Conducted by Habbt F. 



WiTHBBBT, P.Z.S., M.B.O.U. ... 



Notices of Books 



Books Kbceited 



Letters : 



Mental Pebspectitb. By W. -Vlfeed Paer (Illus- 

 trated) 



Lichen Growing on Quartz. By J. Alexandre Cook 

 Wireless Telegraphy. — III. Mechanical Representations 



of Electric Actions. Bv G. W. de Tcnzelmann, b..sc. 



(Illustrated) " 



The Land of the Bastides. By GEENriLLE A. J. Cole, 

 M B.I.A., P.G.S 



Microscopy. By John n. Cooke, f.l.s., f.g.s. 



Notes on Comets and Meteors. By W. F. DENNiNa, 



P.B-A.S 



The Face of the Sky for August. By A. Fowlbe, f.b.a.s. 

 Chess Column. By C. D. Locock, b.a. 



Ki!) 



171 

 17t 

 17.5 



179 



ISO 



181 



182 



183 

 183 



184 



187 

 189 



190 

 191 

 191 



THE GREAT INDIAN EARTHQUAKE OF 1897. 



By Charles Davison, sc.d., f.g.s. 



{Concluded from page 1.50.) 



Effects of the Earthquake. 



Fissures. — Prominent among the earthquake effects 

 are the fissures formed in alluvial plains. Mr. Oldham 

 estimates that, where the necessai-y conditions prevail, 

 fissures were fairly frequent over a region which measures 

 about 400 miles from east to west, and about 350 miles 

 from north to south, and present in smaller numbers over 

 one nearly 600 miles in length from east to west. They 

 were naturally more numerous near river-channels and 

 reservoirs, on account of the absence of lateral support, 

 and as a rule were parallel to the edge of the bank, 

 a few hundred yards in length, and varying in width 

 from a few inches to four or five feet. 



Fissures in such positions are usually formed during 

 every severe earthquake. But an interesting poiuu 

 established by the Indian earthquake is that they wei'e 

 also found in places far removed from any water-channel 

 or excavation; sometimes running parallel to, and along 



cither side of, a road or embankment; at other times 

 skirting the foot of hills ; but in every case clearly due 

 to the compression of the alluvium during the passage 

 of the earth-waves. 



JFany other evidences of the same compression were 

 observed. Telegraph posts were displaced sometimes as 

 much as ten or fifteen feet. In one part of the Assam- 

 Bengal railway, the whole embankment, including 

 borrow-pits and trees on cither side, was shifted laterally 

 through a distance of 6 ft. 9 ins. Rice-fields in Northern 

 Bengal, Lower Assam, etc., which had been carefully 

 levciled so that they might be uniformly flooded, were 

 thrown into gentle undulations, the crests of which were 

 occasionally two or three feet above the hollows. The 

 piers of bridges were moved alongside, as well as 

 towards, the stream. Rails were bent over an un- 

 usu.allv large area, the compression caused by the crump- 

 ling being always compensated by expansion elsewhere. 



Sand-Vents, etc. — " Innumerable, jets of water, like 

 fountains playing, spouted up to heights vaiying from 

 18 inches to quite Z\ or 4 feet. Wherever this had 

 occurred, the land was afterwards seen to occupy a 

 sandy circle with a depression in its centre. These 

 circles ranged from 2 to 6 and 8 feet in diameter, and 

 were to be seen all over the country." This was at 

 Dhubri, within the epicentral area. At Maimansingh, 

 close to the south of the same area, these miniature 

 craters seem to have been almost equally numerous, 

 fifty-two being counted within an area 100 yards long 

 and about 20 feet wide. In many districts, trunks of 

 trees or lumps of coal and fossil resin were ejected with 

 the water, and even, in one or two cases, pebbles of 

 hard i-ock weighing as much as half-a-pound. 



Over a large area, river-channels, tanks, wells, etc., 

 were filled up, partly by the out^pouring of the sand, 

 but chiefly by the forcing up of the bottoms. That 

 the latter was the more effective cause is proved by 

 the elevation of the central piers of many bridges cross- 

 ing canals or streams. In this way, channels of from 

 1,5 to 20 feet in depth were obliterated, the bottoms 

 being left level with the banks on either side. 



Immediately after the earthquake, the surface of 

 many rivers rose from two to ten feet, falling again to 

 the nonnal level in the course of a few days. 



Landslips. — Wherever the conditions were favourable, 

 over an area not less than 300 miles in length, numerous 

 landslips occurred. At Cherrapunji, which is within 

 the epicentral area, there appeared to be more landslip 

 than untouched hillside. Near the same district is a 

 small valley, which, according to Mr. Oldham, was " an 

 indescribable scene of desolation. Evervwhere the hill- 

 sides facing the valley have been stripped bare from crest 

 to base. ... At the bottom of the valley was a piled 

 up heap of dehris and broken trees, while the old stream 

 course had been obliterated, and the stream could be 

 seen flowing over a sandy bed, which must have been 

 raised many feet above the level of the old watercourse." 

 Fofafion of Pillars, etc. — At Chatak, which is close 

 to the epicentral area, is an obelisk, built of broad 

 flat bricks or tiles on a base 12 feet square and originally 

 more than 60 feet high. This was split by the earthquake 

 into four portions. The two upper pieces, about 6 and 

 9 feet long, were thrown down ; while the third, 22 

 feet long, remains standing, but has been twisted through 

 an angle of 30° with respect to the lowest part, which 

 is unmoved. 



Since the great Calabrian earthquake of 1783, this 

 effect of a strong shock has been well known, and very 



