seven o'clock
Paul bore upward , and at the level mentioned he straightened the machine with her nose once more pointed eastward , and the compass hand pointing along the left wing of the machine . It was now growing dark . Not knowing whether this was caused by the closing in of the clouds or the natural declension of the sun , Bob looked at his watch . To his surprise he found it was seven o'clock Panama time , which would make it probably close to nine in their present locality . Night should now be upon them . As it had been decided to let John and Tom operate the night shift , at least for the first few days , John now took his trick at the throttle , changed to the fresh engine , and Bob and Paul turned into their hammocks for the first sleep aboard the airplane . They were both pretty tired , as each had spent several hours at the helm that afternoon , and it was only a few minutes before the gentle rocking of the plane on the billows of air had sent them into a sound oblivion .