About three o'clock
They sat far apart , their knees pulled up , heads bowed . Once when the heat seemed unbearable , Tom opened one side of the cloth in a desperate hope that it might be a little cooler outside . A blast of hot air entered the makeshift tent and he quickly closed the opening . About three o'clock Roger suddenly slipped backward and lay sprawled on the sand . Tom opened one of the containers of water and dipped his shirttail into it . Astro watched him moisten Roger 's lips and wipe his temples . In a few moments the cadet stirred and opened his eyes .