When the desert people conduct an ostrich hunt, it is for the purpose of capturing birds to be incorporated into their herds. They go out in numbers on fleet horses, circle widely to fixed stations, and the chase begins. The fleeing ostrich for a time can outrun the swiftest horse. Therefore, the pursuer keeps going until his horse lags, whereupon he gives way to another horseman. A desert creature, strangely enough the ostrich is not inured to great heat, and sometimes when being pursued under a hot sun will suddenly keel over, dead of apoplexy. Some of the above Ali explained to the boys as they lurched forward on camel-back. It was not their intention to kill an ostrich, but, if possible, to capture one. For this purpose, Ali had provided lengths of rope, weighted at each end, which if well cast would wrap around the legs of an ostrich and bring it down. Bags to be clapped over the head also had been provided. Ali smiled discreetly to himself, however, realizing that on camel-back and without practise, it was next to impossible that either Jack or Bob would succeed in bagging an ostrich. The latter pair, however, while resolved to do their best, given the opportunity, were under no illusion, either. They did not count on capturing an ostrich. What they sought was a closer view of them, a chase and the attendant excitement. That would repay them for the trip, would provide a welcome break in the dullness of their days. Before leaving, each had taken with him a small radio receiving set, fastened in the crown of the solar topee or sun hat. It differed materially from the set Frank had borne on camel back as they approached the oasis, and over which they had received Professor Souchard’s last message. This set was built on a small panel fastened on the inside of the sun helmet. To use it, it would be necessary to halt and set up an aerial and bury a ground. The ground, a small mass of zinc, was carried slung to Bob’s saddle, and the aerial—seventy-five feet of thin wire, hung coiled in the same place. A pair of jointed steel rods, of special construction, both light and durable, was strapped to his rifle scabbard. Before returning, it was planned to set up the aerial, and test whether Frank had succeeded in repairing the Professor’s sending station. Presently, surmounting a sand dune slightly in advance of the others, while Bob and Jack still struggled up its sliding slopes, Ali placing the glasses to his eyes saw the ostriches due east and about a mile and a half away. He dropped back at once, cautioning the boys to stay beside him rather than surmount the dune. “Ostriches have very good sight, and almost as good hearing,” he explained. “I will stay here, and do you two work to right and left of me under shelter of these sand dunes until you judge we have the herd encircled. Then I’ll approach and start them. You keep your stations until I turn over the chase to one or other of you. The ostriches will run in a wide circle.”