The desolation here was complete. All around us lay the dunes, monstrous as still leviathans. Here and there, between their strange, suggestive shapes, under the dark sky one could see the ghastly whiteness of the saltpetre in the arid plains beyond, where the low bushes bent in the chilly breeze. I thought of London—only a few days’ journey from me—revelled for a moment in my situation, which, contrary to my expectation, was rather emphasised by the presence of my companions. The gorgeous Spahi, with his scarlet cloak and hood, his musket and sword, his high red leggings, the ragged, sweating captive in his patched burnous, ex-butcher looking, despite his cord emblem of bondage, like reigning Emperor—they were appropriate figures in this desert place. I had just thought this, and was regarding my Sackville Street suit with disgust, when a low, distinct and near sound suddenly rose from behind a sand dune on my left. It was exactly like the dull beating of a tom-tom. The silence preceding it had been intense, for the breeze was as yet too light to make more than the faintest sighing music, and in the gathering darkness this abrupt and gloomy noise produced, I supposed, by some hidden nomad, made a very unpleasant, even sinister impression upon me. Instinctively I put my hand on the revolver which was slung at my side in a pouch of gazelle skin. As I did so, I saw the Spahi turn sharply and gaze in the direction of the sound, lifting one hand to his ear. The low thunder of the instrument, beaten rhythmically and persistently, grew louder and was evidently drawing nearer. The musician must be climbing up the far side of the dune. I had swung round to face him, and expected every moment to see some wild figure appear upon the summit, defining itself against the cold and gloomy sky. But none came. Nevertheless, the noise increased till it was a roar, drew near till it was actually upon us. It seemed to me that I heard the sticks striking the hard, stretched skin furiously, as if some phantom drummer were stealthily encircling us, catching us in a net, a trap of horrible, vicious uproar. Instinctively I threw a questioning, perhaps an appealing, glance at my two companions. The Spahi had dropped his hand from his ear. He stood upright, as if at attention on the parade-ground of Biskra. His face was set—afterwards I told myself it was fatalistic. The murderer, on the other hand, was smiling. I remember the gleam of his big white teeth. Why was he smiling? While I asked myself the question the roar of the tom-tom grew gradually less, as if the man beating it were walking rapidly away from us in the direction of Sidi-Massarli. None of us said a word till only a faint, heavy throbbing, like the beating of a heart, I fancied, was audible in the darkness. Then I spoke, as silence fell. “Who is it?” “Monsieur, it is no one.” The Spahi’s voice was dry and soft. “What is it?”