What a splendid sight there is from my lofty look-out! the whole of this mighty spectacle displays itself almost without a sound that I can hear. Only a few voices of birds, but no cry of any other animal reaches my ears. But as the breeze rises more and more towards evening, there begins in my immediate neighbourhood a strange and beautiful concert, that is already familiar to me. And now, as the wind blows more and more strongly through the perforated gall-nuts that hang on every tree above us, there resounds through the desert silence a strange melody, a strange language of musical notes that only the sound of the Æolian harp can to some degree represent. These nut-galls on the acacias are bored quite through, and in many cases become the dwelling-places of small ants. If one disturbs them by tapping on the outside of their strange habitation,[33] they come swarming out to fight with the disturber of their peace! It is not so often that their strange ways and doings concern a human being, but it comes to pass to-day. The watchful observer takes delight not only in the sound of these strange musical instruments, but also in the thought that they give shelter to a little world of their own, a peculiarly organised little state made up of living beings, just as the wide endless wilderness below them is a state with the various larger wild animals for its inhabitants. [Illustration: _C. G. Schillings, phot._ GRANT’S GAZELLES (_GAZELLA GRANTI_, Brooke).] My diary records yet another kind of natural observatory, a giant tree uprooted on a wooded river-bank. Here, as it were, in the gallery of the wood, the huge trunk felled by the storm-wind offered me an inviting seat among its branches, and thence I enjoyed many a sight of the animal world around.