[Footnote 31: That most resourceful of travellers, Sir Samuel Baker, once put an ant-hill of this kind to a singular use. The incident may be new to some of my readers. The explorer wished to make soap in the Soudan. “I had neither lime nor potash, but I shortly procured both. The hegleek-tree (_Balanites Egyptiaca_) was extremely rich in potash; therefore I burned a large quantity, and made a strong ley with the ashes; this I concentrated by boiling. There was no lime-stone; but the river produced a plentiful supply of large oyster-shells, that, if burned, would yield excellent lime. Accordingly I constructed a kiln, with the assistance of the white ants. The country was infested with these creatures, which had erected their dwellings in all directions; these were formed of clay so thoroughly cemented by a glutinous preparation of the insects, that it was harder than sun-baked brick. I selected an egg-shaped hill, and cut off the top, exactly as we take off the slice from an egg. My Tokrooris then worked hard, and with a hoe and their lances, they hollowed it out to the base, in spite of the attacks of the ants, which punished the legs of the intruders considerably. I now made a draught-hole from the outside base, at right-angles with the bottom of the hollow cone. My kiln was perfect.” (“The Nile Tributaries of Abyssinia,” pp. 424, 425.)] [Footnote 32: I have seen living trees of the height of ninety feet, the bark of which had been entirely converted into a layer of “white ant earth.”] [Footnote 33: “My sight was now delighted by frequent views of the summits of the Simyen mountains, thickly covered with snow. As this was the month of April, one of the hottest, I can easily believe that some of these mountains are never free, but are within the region of perpetual winter. They are the highest in Abyssinia, attaining an elevation of fifteen thousand feet in Aboo Yared, the loftiest peak.” (Dufton, “A Journey through Abyssinia,” p. 196.) The heights of Simyen lie north-east of Lake Tsana, between the lake and Adowa.] [Footnote 34: “The Geerar is a typical mountain river in a country consisting almost wholly of impervious basaltic and granite rocks; it is evidently a furious torrent after rain, but dry except for the merest trickle at other times; it runs in a deep narrow valley, shut in, hot, and airless, and probably very unhealthy.” (Sir W. Garstin, “Report upon the Basin of the Upper Nile,” 1904.)] [Footnote 35: “Mittheilungen der Afrikanischen Gesellschaft in Deutschland,” vol. iii., 1881.]