Throwing himself flat on the brown hilltop, Ballard trained his glass first on the inner valley reaches of a bridle-path leading over the southern hogback. There was no living thing in sight in that field, though sufficient time had elapsed to enable the Mexican to ride across the bridge and over the hills, if he had left the camp mounted.
The engineer frowned and slipped easily into the out-of-door man's habit of thinking aloud.
"It was a bare chance, of course. If he had news to carry to his master, he would save time by walking one mile as against riding four. Hello!"
The exclamation emphasised a small discovery. From the hilltop the entrance to the colonel's mysterious mine was in plain view, and for the first time in Ballard's observings of it the massive, iron-bound door was open. Bringing the glass to bear on the tunnel-mouth square of shadow, Ballard made out the figures of two men standing just within the entrance and far enough withdrawn to be hidden from prying eyes on the camp plateau. With the help of the glass, the young engineer could distinguish the shape of a huge white sombrero, and under the sombrero the red spark of a cigarette. Wherefore he rolled quickly to a less exposed position and awaited developments.
The suspense was short. In a few minutes the Mexican foreman emerged from the gloom of the mine-mouth, and with a single swift backward glance for the industries at the canyon portal, walked rapidly up the path toward the inner valley. Ballard sat up and trained the field-glass again. Why had Manuel gone out of his way to stop at the mine? The answer, or at least one possible answer, was under the foreman's arm, taking the shape of a short-barrelled rifle of the type carried by express messengers on Western railways.
Ballard screwed the glass into its smallest compass, dropped it into his pocket, and made his way down to the camp mesa. The gun meant nothing more than that the Mexican had not deemed it advisable to appear in the construction camp armed. But, on the other hand, Ballard was fully convinced that he was on his way to Colonel Craigmiles as the bearer of news.
It was an hour later when Otto, the colonel's chauffeur, kicked out the clutch of the buzzing runabout before the door of the office bungalow and announced that he had come to take the convalescent back to Castle 'Cadia. Bromley was still asleep; hence there had been no opportunity for a joint discussion of the latest development in the little war. But when Ballard was helping him into the mechanician's seat, and Otto had gone for a bucket of water to cool the hissing radiator, there was time for a hurried word or two.