488 



NATURE 



Yanjtse ... 

 Plate 



Shat-el-Ar.ab 

 Ganges, 



Ghazepoor ...\ 

 Indus 

 Atrato 



Nile 



VcIlo«- Kiver 



Po ... 



Cubic feet.' 



2.453,026 



1,800.000 



(By Belim and 



Capt. U'uckey) 



(By myself) 



6iS,ooo 



(By Mcs.srs. Hum- 



Iihreys and Abbot) 



300,321 



235,461 



=03,485 



(By the Rev. Mr. 



Everest) 



199,476 



185,274 



130,032 



n 6,000 



(By Sir George 



Staunton) 



91.935 



(By Prof. Prest- 

 wicli) 



7,474>ooo,ooo 

 (By Messrs. Hum- 

 phreys and Abbot) 

 1.255.500,000 

 (By Mr. Ch. 

 Hartley) 



6,368,000,000 



(By the Rev. Mr. 



Everest) 



17.520,000,000 



(By Sir George 



Staunton) 



594,000,000 



405,420,000 



(By M. Lom- 



bardini) 



So.ooo.ooo 



(By myself) 



1.865,900 



(Hu.xley's 



■Physiography.") 



I foot in 3,707 



years. 



(By myself) 



I foot in 29,400 



years. 



(Calculated from 



Mr. Higgin's 



estimate) 

 I foot in 6,000 



years. 



(By Mr. Croll) 



I foot in 6,846 



years. 



I foot in 2,358 

 years. 



: foot in I, 

 years. 



I foot in 25,218 



years. 

 I foot in 9,600 



(Huxley's 

 Physiography.") 



We have now the necessary "data" for considering these 

 three rivers in their conjoint character. Together they 

 drain an area of 1,105,000 square miles; they discharge 

 a body of v.-atcr equal to Sg4fioo cubic feet every second ; 

 and they carry down every jcar to the sea 24,028,800,000 ' 

 cubic feet of sediment, which represents a rate of subaerial 

 denudation equal to the removal of one foot of solid rod: 

 in 1,68/ years. 



If we look upon the Yang-tse, the Yellow River, and 

 the Pei-ho as labouring, with the assistance of the gradual 

 elevation of the sea-border which is at present going 

 on, to e.\tend the territory of China seaward towards 

 her ancient coast-line — represented by a line running 

 from Kamtschalka through the Kurile Islands, Japan, the 

 Loo-choo group, Formosa down to the Malay Archi- 

 pelago ; ■■ and carry ourselves forward into the future 

 V. hen such task is completed and the waves of the Pacific 

 beat once more against this old sea-border, we shall not 

 have much difficulty in picturing to ourselves what will 

 then be the state of matters. In the place of the gulf of 

 Pe-chili and the Yellow Sea there will be vast alluvial 

 plains traversed by the waters of the Yang-tse, the Yellow 

 River, and the Fei-ho ; but before the ancient coast-line 

 is reached they will have joined to form one great river 

 and one united delta. If the Yellow River confines itself 

 mosriy in future ages to its course into the gulf of Pe-chili. 

 that gulf will be filled up in process of time ; and the 

 Hoang-ho winding along through the bed of this obliterated 

 sea will, after being joined by the Pei-ho, turn its course 

 southward, dellected by the Corean peninsula, until it 

 meets at length its sister stream. On the other hand, 

 should the Yellow River be mostly occupied in future in 

 advancing its southern delta it will'join the Yang-tse at a 

 period much less remote from the present ; and their 



_ "Where not otherwise mentioned I have obtained my information of the 

 discharge of water and sediment from the " Earth." by Klisc'e Reclus. 



= This estimate .also includes the solids held in solulion. 



3 In Page's "Advanced Text-book of Geology" Staunton's estimate of 

 the sediment discharged by the Yellow River has been erroneously applied 

 to all " the great Chinese rivers. " 



■J' 'u'^L? •'^>"^'' °" ''"^ subject, by Mr. A. S. Bickmore, read before the 

 North China branch of the Asiatic Society in November, 1867. 



{Scpi. 23, 1880 



united waters will pursue an eastedv direction subse- 

 quently to be joined by the Pei-ho, which will have been 

 gradually finding its way through the gulf of Pe-chili and 

 the Yellow Sea during the preceding ages. In either, 

 event the union of these three rivers would follow. 



Such being the case, it may be interesting to speculate 

 on the time required by these rivers to fill up the seas 

 into which they discharge their sediment. Sir George 

 Staunton estimated that at the rate the Hoang-ho was 

 discharging sediment it would fill up the Yellow Sea and 

 the gulfs of Pe-chili and Lian Tung in 24,000 years ; but 

 M. Elisde Reclus is of opinion that this estimate ought to 

 be doubled, as the Yellow Sea is much deeper than Sir 

 George Staunton stated it to be (20 fathoms). On care- 

 fully e-xamining the latest charts of these seas I am 

 inclined to consider that this estimate cannot be assailed 

 on this point, as my own determination of the average 

 depth is 22 fathoms. 



We will now attempt to gauge the time that the 

 three rivers in question would require to fill up by the 

 sediment they deposit the portion of sea which is 

 included by the gulfs of Pe-chili and Lian Tung, the 

 Yellow Sea, and the Eastern Sea north of the 29th parallel 

 and west of the 126th meridian. I have placed the total 

 surface area at 200,000 English square miles, and the 

 average depth at 26 fathoms ; and following Sir George 

 Staunton's mode of estimation I find that it would take 

 si.xty-six days to form an island a mile square reaching up 

 to the surface of the sea. At this rate it would require 

 36,000 years to form all the sea in question into dry land, 

 supposing of course that there was no elevation or 

 depression of the se.i-bottom during that period. But, 

 the recent formation of several islands and shoals in the 

 Yang-tse estuary, the occurrence of raised beaches and 

 marine remains at Hang-chau, Wusung, and Cliefoo, with 

 other similar evidences, demonstrate that there is an 

 elevation of the coast going on at present ; and, in that 

 case, it will require considerably less than 36,000 years to 

 form the sea into ic>->-a firnta. Perhaps Sir George 

 Staunton's original estimate for the Yellow River may 

 not be far wrong when applied to the whole sea in 

 question. 



PHYSICS WITHOUT APPARATUS^ 

 VI. 

 A COUSTIC.'\L expertments require, for the most part, 

 -'*- the aid of some good instrument or valuable piece 

 of apparatus. Nevertheless a few instructive illustrations 

 of the principles of the science can be improvised without 

 difficulty. Firstly, there is the familiar experiment 

 brought into fashion, we believe, by Prof. Tyndall, of 

 setting a row of ivory billiard balls or glass solitaire 

 marbles along a groove between two wooden boards, 

 and showing how their elasticity enables them to transmit 

 from one to another a wave of moving energy imparted 

 to the first of the row, thus affording a type of the 

 transmission of sound-waves from particle to particle 

 through elastic media. Then wa may show how sounds 

 travel through solid bodies by resting against a music- 

 box or other musical instrument, a broomstick, or any con- 

 venient rod of wood, at the other end of which we place our 

 car. A kindred experiment, illustrative of the transmission 

 of sounds through threads, is depicted in Fig. 20. A large 

 spoon is tied to the middle of a thin silken or hempen 

 thread, the ends of which arc thrust into the ears upon 

 the ends of the thumbs. If the spoon be dangled against 

 the edge of the table it will resound, and the tones reach 

 the ear like a loud church bell. The thread telephone or 

 " lover's telegraph," is upon the same principle, the 

 thread transmitting the whispered words to a distance, 

 without that loss by spreading in all directions which 

 takes place in the open air. 



' Continued from p. 464. 



