A short time before, the youths were successful in persuading their fathers to take them on an expedition to unexplored Brazil. Here they helped the naturalists shoot and classify wild animals, birds, and reptiles and had many thrilling adventures with wild animals and savage Indians. How they fought hand-to-hand with a huge jaguar, barely prevented themselves from being crushed by a terrible anaconda, battled against rapids, and finally became lost and wandered for days in the world's greatest jungle are told in the first volume of this series, entitled, _Lost in the Wilds of Brazil_. The boys spent the following winter finishing up in high school, and scarcely was graduation over when their fathers were requested by the museum to make an expedition to the Sahara Desert to collect specimens of any animal life that might be present in the remote interior. Dr. Kirshner, of whom something has been said, wished to accompany the naturalists to investigate the remains of ancient civilizations. At once Bob and Joe requested that they be taken also, and after careful consideration their elders at last consented. What the boys were particularly looking forward to was taking motion pictures of the desert, for they had been engaged by the Neuman Film Corporation to get many unusual scenes. Less than a week later the expedition sailed on the steamer _Sylvania_ and made the long voyage without any special incident. Now let us return to the boys, as they advanced into their elders' room. At once their mood changed, an expression of astonishment, later turning to anger, creeping over their faces. Everything in the room was in the wildest disorder. Clothes, shoes, satchels, rifles, papers lay scattered about, the scene suggesting that a cyclone had visited the place. It was most deplorable, and the travelers stood for some time as if trying to catch the true meaning of it all. Finally their anxiety caused them to move forward and inspect the belongings. "Good thing we didn't have the treasure map," remarked Mr. Lewis, examining the contents of a small black bag. "It wouldn't be here now." At the end of their inspection the explorers found that nothing had been taken from their belongings. It appeared that the crafty Arabs wished only the treasure map, and that, not being able to find it, they had left without any other spoils. "They sure acted in wild haste," observed Mr. Holton. "It's almost impossible to see how all this could have been torn up so quickly. It wasn't five minutes from the time that you boys told of seeing the men that we were up here." "Trust the Arabs to do that," said Dr. Kirshner, with a dry smile. The scientists' possessions were placed back in their proper places, and then they went to inspect the room occupied by Bob and Joe. "Probably nothing taken from here, either," was the opinion expressed by Mr. Holton, and he proved right, as they later found.