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THE POPULAR SCIENCE MONTHLY. 



in prehistoric times by rivers that ran 

 through the present dry sand-channels which 

 the Arabs call Bahr-et-Abied, or rivers 

 without water. The fact that river-shells 

 were discovered in these beds during the 

 French expedition to Egypt lends some sup- 

 port to this view. M. Delamotte has de- 

 voted some twenty years to the examination 

 of the subject, and, while he does not un- 

 dertake to determine when the rivers wer"e 

 dried up, he has reached a conclusion as to 

 the manner in which it was done. He be- 

 lieves that the whole plateau of Khartoum 

 was in prehistoric times a grand lake whence 

 the Nile issued as it now issues from the 

 Victoria and Albert Nyanzas. The cata- 

 racts were, however, higher than they are 

 now, and the river, instead of precipitating 

 the whole mass of its waters over the rocks, 

 was divided into streams which found their 

 way through the channels marked by the 

 present Bahr-et-Abiad, and carried the wa- 

 ter into the parts of the country which are 

 now desert. The granite and porphyry of 

 the cataract were gradually worn away in 

 the course of ages, their level was low- 

 ered, and the Nile, instead of being forced 

 into branch-channels, fell over them and 

 concentrated its waters into its present 

 single stream. M. Delamotte is examining 

 the region of the Upper Nile again, for the 

 purpose of verifying his theory, and of de- 

 termining if it is possible, by constructing 

 a system of dams and sluices, to raise the 

 level of the cataracts, and cause the waters 

 to flow again through the channels they 

 have deserted. 



Sports in the Colors of Squirrels. A 



correspondent of "Forest and Stream" 

 relates an interesting instance of the de- 

 velopment of varieties of colors in squir- 

 rels, which took place in South Carolina 



several years ago. A Mr. K , who owned 



a considerable plantation in the county of 

 Marlborough, had presented to him a pair of 

 milk-white squirrels. His woods were much 

 frequented by gray squirrels, and fox and 

 black squirrels were numerous in the pines 

 and cypress-swamps at some distance from 

 the plantation. The white squirrels bred, 

 producing two young ones, also milk white. 

 The animals were very prolific, under the 

 protection of the owner, who prohibited the 



intrusion of hunters, and, in course of time, 

 spread to the adjoining plantations, and 

 many of them took to the immense swamps " 

 bordering on the Big Peedee River. They 

 also began to sport and change their color, 

 and, from being pure white, became marked 

 with every possible variation of black and 

 white. The correspondent who relates these 

 facts has killed, at various times, at least a 

 dozen thus marked. One of them was of a 

 deep, sparkling black color, except as to the 

 ears and the large, bushy tail, which were 

 enow-white, save a small commingling of the 

 black and white at the root of the tail, and 

 the lower part of the belly and the inner 

 edge of the flanks, which were of a clear 

 ash-gray. The varieties seem to have almost 

 disappeared since the war. In the last indi- 

 vidual that the correspondent has noticed, 

 the markings were less pretty and the colors 

 less distinct ; the white was turning to ash 

 and the black to brown, the consequence, he 

 supposes, of wild breeding. 



A New African Tribe Dr. Emil Halub 



recently addressed the London Geographi- 

 cal Society respecting a hitherto undescribed 

 African tribe called the Marutse. They in- 

 habit the country formerly ruled by the Ma- 

 kololo, described by Dr. Livingstone, who 

 have ceased to exist. Dr. Halub said that 

 when he crossed the Zambesi, and entered 

 into their country, it seemed that he had left 

 Africa, for the tribes were entirely different 

 from the others in South Africa. They be- 

 long to the Banti family, but differ from the 

 other members of this family in their ap- 

 pearance, customs, and workmanship. They 

 have their own civilization, independent of 

 influence from white men ; and, while the 

 other tribes have nothing which could be 

 called a religion, they believe in a Supreme 

 Being and in a life after death. They call 

 the Supreme Being N'yambe, but have so 

 great a reverence for him that they do not 

 like to pronounce his name. Whenever a 

 serious event happens, as when a man is 

 killed by a buffalo, a crocodile, or an ele- 

 phant, the common expression is " N'yambe 

 has ordered it, and it is no use resisting." 

 When a member of the royal family was ill, 

 he was taken to the grave of one of his an- 

 cestors, when the king knelt on the grave, 

 and prayed to the deceased, " You, my 



