"I will tell you a tale," he said. "It happened many years ago in Senegal. I was quartered in a remote station, and to pass the time used to go fishing for big barbel in the river. A little Arab mare used to carry my luncheon basket one of the salted dun breed you got at Timbuctoo in the old days. Well, one morning I had good sport, and the mare was unaccountably restless. I could hear her whinnying and squealing and stamping her feet, and I kept soothing her with my voice while my mind was intent on fish. I could see her all the time, as I thought, out of a corner of my eye, tethered to a tree twenty yards away. After a couple of hours I began to think of food. I collected my fish in a tarpaulin bag, and moved down the stream towards the mare, trolling my line. When I got up to her I flung the tarpaulin on her back "