56o 



NA TURE 



{Ai)ril 



factors are nearly equal, and will be tedious when in is large — 

 i.e. when the factors are very unequal ; and most tedious of all 

 when N is a prime, when the number of steps (w) required will 

 be w = i(A - i) or ^(A — 2), according as A is odd or even, 

 which is obviously a very high number for high numbers N. 



A diffetent "shortening process" is proposed (by Mr. 

 Hudson) on p. 511 of Nature, which amounts to this. When 

 the two numbers (A + r) and {(A + r)- — N^S or, again, when 

 the two numbers (B - r) and {(B - rY + N[, have a common 

 measure, that common measure is (as is easily seen) one of the 

 factors of N ; and, if it can be recognized, at once solves the 

 question. Unfortunately, this will be in general of \\\.\\& prac- 

 tical help, except when one of the four numbers operated on is 

 quite small, as otherwise it is not easy to recognize (quickly) 

 the fact of there being a common measure. 



Allan Cunningham, 



Chatham, March 30. Lieut. -Col. R.E, 



THE GEOGRAPHICAL RESULTS OF 

 MR. STANLEY'S EXPEDITION. 



T T is evident from Mr. Stanley's stirring letters, which 

 ■i during the past week have cast all other topics into 

 the shade, that pioneering in Africa is not yet at an end, 

 and that that strange continent has not yielded up its 

 last wonder to knowledge. The letters are suggestive of 

 many things. Much could be said in admiration of the 

 heroism and generalship displayed ; much as to the 

 difficulties encountered and the sufferings and losses sus- 

 tained ; much as to the route selected, and much as to 

 the conduct of the party left at Yambuya. But in the 

 first place this is hardly the proper place to speak of 

 these aspects of the expedition, and in the second place 

 it is only fair to wait for the full narrative before ven- 

 turing upon criticism. No one who knows Mr. Stanley 

 had ever any doubt of his success, or could ever believe 

 that he would allow himself to die before accomplishing 

 his work. It is clear that to anyone who has it in him 

 to do heroic deeds there is still ample-scope in Africa. 



What we have to do with here are the geographical 

 results of Mr. Stanley^s expedition. And here again we 

 are met by the fact that the expedition was not properly 

 one of exploration ; at least, this feature was only second- 

 ary to the main object of the expedition, the "relief" 

 of Emin Pasha, himself a contributor to science of high 

 rank. Again, even the communication to the Royal 

 Geographical Society can only be regarded as a few 

 preliminary notes on the additions made to our know- 

 ledge of one of the most interesting regions in Africa ; 

 for the full results, which cannot but be of high value and 

 interest, we must wait for Mr. Stanley's full narrative, 

 which will doubtless include the results obtained by 

 the scientific members of his staff. As the region 

 through which the expedition passed was previously 

 entirely unknown, fresh additions to our knowledge 

 Were inevitable. As to the character of this region, 

 it is evident that, so far as time and danger and difficul- 

 ties are concerned, no worse route could have been 

 chosen. It is now well known that the Committee and 

 Mr. Stanley yielded to influences which ought not to 

 have weigheJ with them, in view of the main purpose of 

 the Expedition, and that Mr. Stanley's own preference 

 would have been for the East Coast route. Had this 

 route been selected, no doubt there might have been diffi- 

 culties with the Masai ; forests would have had to be 

 traversed, deserts crossed, and swamps trudged through ; 

 but all these obstacles combined would have been trifling 

 compared with the terrors of the Aruwimi jungles, and 

 their suspicious and ferocious inhabitants. However, 

 Science has nothing to complain of: the gain has been all 

 on her side. 



Mr. Stanley has passed through one of the great 

 blanks of Central Africa. Much of it was untrodden 

 even by the deadly foot of the Arab slaver. Dr. Junker 



just touched its northern fringe ; he had reached the 

 Nepoko River apparently in its upper course ; but from 

 about 3° N. to about 4° S., and between the Upper Congo 

 on the west and the lakes on the east, we have virtually a 

 great blank. It is the northern part of this blank which 

 Mr. Stanley has enabled us to fill in ; and when he comes 

 home he will probably be able to tell us more than we 

 yet know. In the particular region with which he was 

 concerned we wanted to know the course of the Aruwimi 

 and its tributaries ; the character of the country and 

 people through which it passes ; the position and extent 

 of the lake (Muta Nzig^) to the south of Albert Nyanza, 

 and its relation either to the Nile or the Congo. Some 

 of these problems Mr. Stanley has solved ; others, no 

 doubt, he will have solved by this time. 



One thing is clear, the Expedition passed through the 

 northern section of what is probably the greatest forest 

 region in Africa, extending from about 3° N. to 4° S., and 

 from about 23° to 30° E. Junker met with it on the 

 Nepoko, and Livingstone in his weary journey from Tan- 

 ganyika to Nyangwe. It was dense enough in both 

 cases, but nothing apparently compared with what 

 Stanley found it to be on the Aruwimi. The route, he 

 tells us, was covered with creepers varying from ^ of an 

 inch to 15 inches in thickness, swinging across the path 

 in bowhnes or loops, sometimes matted and twisted 

 together ; also of a low, dense brush occupying the sites 

 of old clearings which had to be carved through before a 

 passage was possible. Where the clearings had been 

 abandoned for some years was found a young forest, the 

 spaces between the trees choked with climbing plants and 

 vegetable creepers. This had to be tunnelled through 

 before an inch of progress could be made. Mr. Stanley's 

 description of the character and extent of this forest in 

 his letter to Mr. Bruce is quite worth quoting : — 



"Take a thick Scottish copse, dripping with rain; 

 imagine this copse to be a mere undergrowth, nourished 

 under the impenetrable shade of ancient trees, ranging 

 from 100 to 180 feet high ; briars and thorns abundant ; 

 lazy creeks meandering through the depths of the jungle, 

 and sometimes a deep affluent of a great river. Imagine 

 this forest and jungle in all stages of decay and growth — 

 old trees falling, leaning perilously over, fallen prostrate ; 

 ants and insects of all kinds, sizes, and colours murmuring 

 around, monkeys and chimpanzees above, queer noises of 

 birds and animals, crashes in the jungle as troops of 

 elephants rush away ; dwarfs with poisoned arrows 

 securely hidden behind some buttress or in some dark 

 recess ; strong brown-bodied aborigines with terribly sharp 

 spears, standing poised, still as dead stumps ; rain patter- 

 ing down on you every other day in the year ; an impure 

 atmosphere, with its dread consequences, fever and 

 dysentery ; gloom throughout the day, and darkness 

 almost palpable throughout the night ; and then, if you 

 will imagine such a forest extending the entire distance 

 from Plymouth to Peterhead, you will have a fair idea of 

 some of the inconveniences endured by us from June 28 

 to December 5, 1887, and from June i, 1888, to the pre- 

 sent date, to continue again from the present date till about 

 December 10, 1888, when I hope then to say a last fare- 

 well to the Congo forest." 



Here, then, we have a forest region very different from 

 any other forest region of any extent in Africa. Prof. Drum- 

 mond, in his recent book on Africa, describes very clearly 

 the typical forest of Central and Southern Africa ; the trees 

 mostly standing apart, with very little brushwood, and in 

 many places no difficulty in penetrating it even with a 

 Cape cart. The rank exuberance of the Aruwimi forest can 

 hardly be due to the abundance of water in the shape of 

 lakes and rivers ; for away south in the region recently 

 traversed by Mr. Arnot, the region described by Living- 

 stone as a great sponge, where the feeders of the Zambesi, 

 the Congo, and other great rivers, take their rise, and 

 on the east of which lie Tanganyika and Bangweolo 



