seven o'clock
Paul and Bob now relieved Tom and John , and the latter young men took a nap . It was their custom to work in pairs , the observer preparing food for himself and the pilot during the course of flight . Sometimes the observer took the throttle long enough to give his friend a chance to eat , and sometimes the pilot retained his seat , allowing the automatic arrangement to do the guiding for him while he munched his food . Just before seven o'clock Paul and Bob saw two large bodies of water ahead of them , one stretching to the right and the other to the left . The chart told them that the northern body was the Red Sea and the southern one the Gulf of Aden , which opens into the Indian Ocean . Between these bodies lay a narrow belt of water , flanked on the western or African side by rocky , wooded hills , and on the eastern side by low , sandy shores dotted with palms . This was the Strait of Bab-el-Mandeb , and the country beyond was Persia .