392 



NATURE 



[August 23, 1900 



peculiarities which may either react upon each other, or 

 the origin of which must be sought in a common source. 

 From two independent investigations come attempts 

 to trace a connection between the amount of the Nile 

 floods and the abundance or deficiency of the south-west 

 monsoon rainfall in India. Mr. Willcocks broached this 

 subject in a paper read before the meteorological 

 congress at the World's Exposition in Chicago, and 

 there suggested that famine years in India are generally 

 years of low flood in Egypt, and that when the summer 

 supply of the Nile had been deficient and late, a high 

 flood might well follow, since the drought in the valley 

 of the White Nile must create a powerful draught from 

 the Indian Ocean or the Arabian Sea, a district in which 

 is to be sought the origin of the massive current of the 

 south-west monsoon. Unfortunately, any exact data to 

 establish this interesting connection are not forthcoming, 

 and can hardly be expected, since the Nile is supplied 

 from two distinct sources, and it is impossible to separate 

 and trace the effect of either contribution. Of the great 

 lakes of Central East Africa which constitute a reservoir 

 for the Nile waters, little is known as to the variation 

 in their relative height due to the rainfall in their 

 vicinity, which lasts from March to December. At Port 

 Alice, on the Victoria Nyanza, and at some other 

 stations, observations, more or less regular, are made of 

 the variation in the heights of the water, but in the 

 absence of any common datum level these heights are 

 referred to that of the mean lake. Much surveying work 

 and long-continued observations will have to be made 

 before these scanty statistics can be turned to full 

 account. Of the second source of supply to the Nile, 

 viz. the flood waters in the Atbara, the Blue Nile and 

 other rivers, fed during the rainy season from June to 

 November, we know practically nothing as to their 

 amount. But if is this seasonal supply which is prob- 

 ably the greatest factor in causing variations in the Nile 

 floods, and where a connection with the causes of the 

 Indian rains is closest. Whatever influences the flow of 

 the monsoon current from the equator northwards over 

 the Indian seas towards the heated regions of India and 

 the Malay Peninsula must have a proportional effect on 

 East Africa and South Arabia. With heavy monsoon 

 rains, therefore, it is not unlikely that the contributing 

 rivers add materially to the volume of the Nile waters, 

 but it is not altogether a trustworthy guide to gauge the 

 amount of water that enters the Nile by measuring the 

 quantity that passes a particular station. Much water 

 enters the Nile that never contributes to the irrigation of 

 Egyptian lands. Of the amount lost by evaporation no 

 account can be taken, but a source of greater error arises 

 from the peculiar flatness of the ground about Shambe, 

 which forms the apex of the swamp delta. Here the 

 Nile can spread its waters over a large area, and 

 practically lose itself as a river among the beds of reeds 

 and rushes, which form a veritable swamp. Engineering 

 works, already projected or actually begun, aim at clear- 

 ing some or other of the feeding streams, such as the 

 Bahr el Gebel or the Bahr el Zarab, and the effect must 

 be, when completed, to break the continuity of such 

 observations as have been made. Other sources of error 

 are to be found in the varying quantity and character of 

 the " sudd" which may interrupt the flow or diminish the 

 amount of evaporation ; but without insisting on too 

 much accuracy, there exists a certain amount of evidence 

 that the two great agricultural countries of Egypt and 

 India are likely to be prosperous together or to suffer in 

 common. 



Mr. Eliot, the meteorological reporter to the Govern- 

 ment of India, in his recent forecast of the probable 

 character of the south-west monsoon rains of 1900, not 

 only fully endorses Mr. Willcocks' statement, but adds 

 some statistics which render a connection highly 

 probable. Omitting a few local particulars from Mr. 



NO. 1608, VOL. 62] 



Eliot's statistical summary, the broad features are shown 

 below. 



The years of excess of Indian rainfall tell a similar 

 tale, even more distinctly. 



1878 



1886 

 1892 

 1893 

 1894 



Having mentioned some of the causes which prevent 

 a rigorous comparison between the Nile floods and the 

 Indian rainfall, one is not unprepared to find some dis- 

 crepancies ; but Mr. Eliot certainly does not overstate 

 his case when he contends that these tables indicate that 

 in at least four out of five seasons in which there was a 

 partial failure of the rains in India there was a low 

 Nile, and that generally the two countries are similarly 

 affected by the meteorological conditions and the varia- 

 tions of those conditions. The causes of these variations 

 are obscure, and at present very imperfectly recognised, 

 for a complete solution, as Mr. Eliot points out, demands 

 a much more intimate knowledge of the atmospheric 

 conditions that prevail over a large area. The meteorology 

 of Australia and the Indian Ocean, and perhaps also of 

 the Antarctic Ocean, must be linked on to that of the 

 Indian monsoon area " before it will be possible to ascer- 

 tain the missing factors necessary to complete the ex- 

 planations of the relations between the chief features of 

 the monsoon currents and rainfall of India and the 

 antecedent and concurrent conditions in the Indian area 

 and the regions to the south." To trace and anticipate 

 the effect of weather conditions over the area that 

 embraces both India and Egypt, in which our interests 

 are so largely involved, should stimulate further inquiry, 

 with the result of placing at the command of science 

 additional means for dealing with so grave a problem. 



THE FORTHCOMING MEETING OF THE 

 BRITISH ASSOCIATION AT BRADFORD. 



IN the last article on the subject of the forthcoming 

 meeting of the British Association an account was 

 given of the handbook that is to be published in connec- 

 tion with the visit, and some information was furnished 

 in regard to hotel and lodging accommodation. In the 

 present article it is proposed to give a description of the 

 excursions arranged by the local committee. 



Following the custom of former years, it has been 

 arranged that half-day excursions only shall take place on 

 the Saturday, and that the whole-day excursions shall be 

 reserved until the Thursday, when the serious work of the 

 Association will be completed. The only exceptions to 

 this are that the Mayor and Corporation are inviting a 

 small party of engineers to visit their waterworks at 

 Gowthwaite, in the Nidd Valley, and that a party exclu- 

 sively for geologists will travel to Pateley Bridge by the 



