“Whatcommunication have they with the outside?”

“Radio, that’s all.”

“Didn’t they assist in the search for Myra Thomas?”

“Oh, yes. Spent about a week with my gang. Brought a couple of trackers to team with mine. And a side of the best beef we’ve ever lived on. You interested in them extra specially?”

“Only for the same reason that I am interested in the people living at other homesteads to the south and the south-west. If Patsy Lonergan wasn’t mentally unstable due to his solitary life, if he didn’t imagine he saw that helicopter, then that helicopter must have a base, and that base must be on or in the vicinity of the Nullarbor,”

“Well, then, how do you propose to ‘track’ that machine? Search every homestead on the perimeter of the Plain?”

“No. Assuming that we found the helicopter at some homestead, we’d learn nothing excepting that the owner hadn’t registered it with the Civil Aviation Department, and so had been breaking certain regulations. My interest is in the object and purpose for which it is being used onassumably secret missions, and merely locating the base won’t satisfy me if the owner doesn’t choose to talk.”

“You’re right there,” Easter pondered. “What about my first question, about how you intend to ‘track’ that machine Lonergan says he saw?”

“I have letters from Lonergan’s lawyer in Norseman, for the old fellow did own property and a sizable bank account for a prospector-dog-trapper. The letter empowers me, William Black, nephew of the deceased, to take over the camels, equipment and other things once owned by Lonergan and now at Mount Singular. Included in those possessions are the dog traps, and it will be my job to locate them. To do that, I have to back-track the old chap along his trap-line, and locate his camps which he named so peculiarly. And then I have to hope

… hope that I shall see or hear that helicopter, determine where it is going, and learn its business.”