While Gridley slept, the scout plane, carried aft in the keel cabin, was lowered to the ground, where it underwent a careful inspection and test by the engineers and officers of the O-220. Even before the plane was ready Gridley appeared at the cabin door of the O-220 and descended to the ground. "You did not sleep long," said Zuppner. "I do not know how long," said Gridley, "but I feel rested and anyway I could not have slept longer, knowing that those fellows are out there somewhere waiting and hoping for succor." "What route do you expect to follow," asked Zuppner, "and how are you planning to insure a reasonable likelihood of your being able to return?" "I shall fly directly over the forest as far as I think it at all likely that they could have marched in the time that they have been absent, assuming that they became absolutely confused and have traveled steadily away from the ship. As soon as I have gained sufficient altitude to make any observation I shall try and spot some natural landmark, like a mountain or a body of water, near the ship and from time to time, as I proceed, I shall make a note of similar landmarks. I believe that in this way I can easily find my way back, since at the furthest I cannot proceed over two hundred and fifty miles from the O-220 and return to it with the fuel that I can carry. "After I have reached the furthest possible limits that I think the party could have strayed, I shall commence circling, depending upon the noise of the motor to attract their attention and, of course, assuming that they will find some means of signaling their presence to me, which they can do even in wooded country by building smudges." "You expect to land?" inquired Zuppner, nodding at the heavy rifle which Gridley carried. "If I find them in open country, I shall land; but even if I do not find them it may be necessary for me to come down and my recent experiences have taught me not to venture far in Pellucidar without a rifle." After a careful inspection, Gridley shook hands with the three remaining officers and bid farewell to the ship's company, all of whom were anxious observers of his preparation for departure. "Good-bye, old man," said Zuppner, "and may God and luck go with you." Gridley pressed the hand of the man he had come to look upon as a staunch and loyal friend, and then took his seat in the open cockpit of the scout plane. Two mechanics spun the propeller, the motor roared and a moment later the block was kicked away and the plane rolled out across the grassy meadowland towards the forest at the far side. The watchers saw it rise swiftly and make a great circle and they knew that Gridley was looking for a landmark. Twice it circled above the open plain and then darted away across the forest.