"We'll wait and see who is tracking us," he grimly observed to Lessari.
The whining sound of a dog-train continued, borne through the cold void with clear persistence. Rex strained his eyes on the distant mouth of the cañon to mark who came out, but he watched in vain. The noise ceased as suddenly as it arose, and though they dallied another fifteen minutes, nothing could be seen.
"That's odd," commented Britton. "Wasn't it a dog-sled, Lessari?"
"Sound like him much!" answered the Corsican, in an awed voice. He was somewhat superstitious, and he nursed his cut face apprehensively, as if it were responsible for the strange incident.
"I could have sworn to that as the shriek of runners," Rex declared, "but it may have been ice. In any event we can't stop longer. Ho! there–mush, mush!"
They forged on, climbing to a still higher altitude and meeting with a frigid air that reached to the very marrow of their bones. Lessari weakened, and Britton made him take to the sled for the rest of the afternoon while he himself continued his heart-breaking tramp beside the dogs, surmounting all obstacles, no matter how formidable, with that intrepid grit and unbroken muscle-strength which was his heritage.
The short, sub-Arctic day closed in swiftly, shrouding everything with a heavy fog, and night caught the two travellers among the black river boulders.
It was a desolate place of incomparable bleakness in which they were forced to camp, but when the stove was set going inside the pitched tent and they had infused some heat into their frost-tried bodies, the outlook seemed more cheerful.
The next day saw a repetition of their hardships and trials. Lessari declared himself strong enough to keep his feet, but Britton forced him to ride behind the dogs. The Corsican lay wrapped in robes, and the spasms of coughing that wrenched his frame told about how fit he was to travel the trail afoot. There were places so rough and so hard to scale that he could not stay upon the loaded sled while the dogs dragged it over. At such points he was compelled to walk, and Rex had to assist him.
They had penetrated into the timbered regions which flanked the Klondike, and the way grew wilder although there was some solace of shelter. According to Britton's estimate of the Thron-Diuck's directions the place of the five mountains could not be many miles distant, and, even in that soul-chilling waste, his blood warmed every inch of his body when he thought success might soon reward his strenuous stampedes.