196 



NATURE 



[December 7, 191 1 



British Central Africa is drained (a) by the Nyasa-Shir<r- 

 Zambezi outlet, (b) the Loangwa-Zarnbezi, (c) the Luapub- 

 Congo. That portion of the Nyasa-Tanganylka plateau 

 which borders on the route of th«; " Stevenson road " drains 

 in five directions : (i) To Lake Tanjianyika and the Congo, 

 (2) to Nyasa, (3) to the Chozi and Luapuia, (4) to Lake 

 Kukwa, which has no outlet, (5) to the Loangwa and 

 Zambezi. 



But while the bulk of this portion of Africa lies at eleva- 

 tions over 3000 feet, the two main drains to the south, 

 Nyasa-Shire and Loangwa-Zambczi, form deep depressions 

 of considerable width, not attaining an altitude of anything 

 above 1500 feet in their northernmost (highest) parts. 

 One result of this is that British Central Africa has two 

 climates, that of the low country, hot and somewhat 

 unhealthy, and that of the uplands, pleasant and fairly 

 healthy. 



When I first knew Nyasaland, in 1887, there was an 

 available line of water transport some 700 miles in length 

 from the Zambezi mouth to the north end of Lake Nyasa, 

 with one break only, the Murchison cataracts of the Shire 

 River (whi(,h extend for some 40 miles). During recent 

 times the couise of the Shire has so rapidly and per- 

 sistently silted up, both above and below the cataracts, that 

 at the present day the upper portion is almost unnavigable 

 at any season, and thr lower river, instead of being avail- 

 able as a transport route all the year round from the sea 

 to the foothills of the Shire Highlands, can only be used 

 for a few months of the year so far as the junction with 

 the Ruo River. The Shire gathers very little water on its 

 course, and is the overflow pipe from the Nyasa tank. 

 When that tank almost ceases to overflow, as is the case 

 at present, the pipe must be more or less empty, and no 

 human power can fill it. 



This enforced abandonment to a great extent of the 

 Shire as a transport route has been a terrible handicap on 

 the growing planting industries of Nyasaland, which at 

 this moment is unable to find a means of transporting to 

 the sea-coast the cotton, tobacco, rice, maize, tea, rubber, 

 and other marketable articles she is actually producing. 

 The suggested extensions of the railway north and south 

 will enable the protectorate not only to deal with what she 

 is now producing, but to open up large additional tracts 

 of land. 



For the present fall in level of Lake Nyasa, the result 

 of which is a far scantier and only intermittent overflow 

 into the Shire River, it is difficult to assign any reasonable 

 cause except a decreased rainfall in the basin ; but such 

 observations and records as have been kept at lake stations 

 during the last few years do not seem altogether to bear 

 out this supposition. A theory which might to some 

 extent account for definite cycles of rise and fall of the 

 level of Nyasa (presumably due to lessening and increasing 

 rainfall) has suggested itself to me, and I advance it for 

 what it is worth. We are aware that Tanganyika has a 

 natural outlet to the Congo. When Livingstone and 

 Stanley were there this outlet was found (the Lukugu), 

 but it was blocked up ; it was clear from native evidence 

 that the lake had been rising in level for a number of 

 years. The prophecy was then made that sooner or later 

 it would break out at its old outlet. This subsequently 

 took place, and for years Tanganyika has sent its surplus 

 waters to the Atlantic. I am not aware whether the 

 Lukugu has yet closed again. A noticeable feature on 

 Nyasa is an old beach-mark, 6 or 8 feet above the highest 

 level to which the lake now rises. This mark is distinct 

 and clear, especially on the rocks, and is carried round the 

 lake both in the open and in the most secluded and 

 sheltered bays. It is abundantly evident that at some not 

 very distant time the lake had this higher level, from 

 which there must have been a sudden fall. Some few 

 years ago, during the dry season, Nyasa ceased to over- 

 flow, and the bed of the Shire River at its exit began to 

 silt up, reeds and other plants took root, and natives were 

 able to walk across with only a few inches of water here 

 and there. It would only have needed a few similar 

 seasons for the outlet to have become entirely choked up, 

 as was the case with the Lukugu. Is it not probable, 

 therefore, that this has actually taken place at previous 

 periods, and that the level of the lake subsequently rose 

 until it overflowed the barrier and finallv burst it? Is it 



NO. 2197, VOL. 88] 



not, moreover, probable that these cycle* of fall, bl< 

 up, rise, and outburst have been going on for agea? 

 sort of recurring decimal. 



The Nyasaland basin is verj limited in extent. The 

 of the water which enters the lake comes in .r 

 end from high country lying beyond the ' 

 boundary. Part of this country consists of a «t-i> 

 ing volcanic district in " Kondeland," which is d«' 

 with the craters of extinct volcanoes. On the txa-x 

 Nyasa the watershed between the lake and the in 

 Ocean lies within a few miles. No rivers of any 

 enter the lake from the east. 



To refer to the climate of British Central Af 

 Throughout the higher levels, from May to S'T * 

 inclusive, it would be hard to find a pleasanter 

 October and November are hot, but dry; Decu;.-, 

 March constitutes the rainy season ; .April is cool and 

 (the finishing of the rains). Malaria is, of course, 

 chief trouble. If this could be checked there is no r 

 why the elevated plateaux, not only of British Ceni 

 Africa, but of many other parts of tropical Africa, sF 

 not be as healthy as Queensland. Knowledge which 

 been gained during the last ten years, largely through 

 exertions of the London and Liverpool Tropical Schools 

 Medicine, has enabled us not only to get a very 

 better insight into the causes of malarial fevers, but 

 to some extent to prevent their occurrence. Most tr( 

 diseases are now known to be communicated by 

 biting insects, and if it were possible to protect our 

 against the attacks of these we should be able to pr( 

 fevers. The difficulty, however, is to carry this 

 successfully. 



A few years ago the first cases of sleeping sickness wi 

 discovered in British Central Africa. The disease reai* 

 this part of the continent from the Congo State, havii 

 no doubt, been carried to the shores of Tanganyika 

 Mweru, and to the Luapuia Valley, by the numerous 



Seditions from the Congo to the eastern boundaries of 

 ree State. It quickly established itself on Tangan 

 and Mweru and in the Luapuia Valley, also along 

 banks of several of the larger rivers running into M 

 and Tanganyika. Quite recently cases have appeared 

 the valley of the Luangwa, and also in the country 

 ing on the south-western shores of Lake Nj"asa ; and it 

 evident that there is in this part of .Africa some hith(^ 

 unknown agent which carries the germ of sleeping si 

 ness, as the tsetse-fly known as Glossina palpalis does 

 exist in the protectorate of Nyasaland (although it is fo 

 on Lakes Tanganyika and Mweru). More than one 

 pedition is now at work investigating these inter 

 questions, and especially as regards the connection betw( 

 tsetse-fly and big game. Whatever the results obtaii 

 bv these expeditions may be. however, it is, I thinl 

 already evident that sleeping sickness will not prove to 

 such a scourge in these parts as it has been in Uganda. 



It has been believed by many that the presence of g 

 and especially buffalo, is responsible for the existence 

 tsetse-fly. After many years spent in travelling over 

 part of Nyasaland and much of northern Rhi 

 Portuguese and German East Africa, and the Upper 

 1 arrived at the conclu!^ion that the weight of evidei 

 against this theory, so far as tropical .Africa is cone 

 and in fhis belief, namely, that tsetse in these regions 

 not depend on big game for its existence, I think th 

 who are entitled to speak with authority, including 

 Selous, are now agreed. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



The annual prize distribution and students' convers__ 

 of the Northampton Polytechnic Institute, ClerkenJ 

 E.C., will be held to-morrow, December 8. Sir Wtf 

 H. White, K.C.B., F.R.S.. will distribute the pr* 

 certificates. 



The organising committee for the Imperial Unii 

 Congress to be held in London next July has appi-. 

 Dr. Alexander Hill, formerly Master of Downing CoL^— 

 Cambridge, to be s'^cretary ' to the congress, in succession 

 to the late Dr. R. D. Roberts. 



