He turned away from it and stood staring upward at the sky, sniffing curiously, agitatedly, at the warm air. It was heavily charged with nipping, pungent mist. Flocks of prairie birds were in flight--sage hens, sand owls, linnets--all winging their way westward.

Silk knew the awful meaning of these signs. He ran up the sloping side of the hollow coulee, and when he reached its rim his worst fears were realised. The prairie was on fire!

Far back the whole wide expanse was wrapped in a vast rolling cloud of grey-brown smoke. The rising sun shone dimly through it, red as the flames beneath, that curled and leapt and twisted like a long ocean wave, sending up a spray of sparks into the overhanging gloom.

He heard the fierce crackling of the burning gra.s.s as the fiery tide swept towards him, devouring all in its way. He saw the wild creatures of the prairie bunched together in a moving ma.s.s--elks and antelopes first, then a host of the smaller fry--all bounding along, friend and foe alike, in a frantic stampede.

He was cool, as he always was, in the face of danger; but he knew the value of every moment now, and he ran back to his prisoner.

"Quick! Quick!" he cried, awakening him with a rough shake as he began to untie the rope with which the half-breed was bound. "The prairie's on fire! Look at the smoke! Quick; get to your feet. We've no time to lose.

There's only one horse--my mare. The other's done for, see? You killed it--as you meant to kill me."

"Holy!" exclaimed Pierre Roche. His bronzed face had become suddenly livid. His dark eyes showed the abject terror that had come over him.

"Only one horse? Yours? Den you will abandon me? You will tek your revenge so?"

A ghost of a smile played about the lips of Sergeant Silk. He turned away without answering, and the crackle of the advancing flames grew louder, the hot breath of the burning prairie grew hotter and hotter, the smoke more dense and choking. He went up to his mare, caressed her as he loosened her halter from the bit ring.

"All right, my beauty," he said very tenderly. "Be brave, keep cool. It all depends upon you. But you can do it, eh? At least you'll try."

He flung the saddle over her back and fastened the cinches. Then he led her to where Pierre Roche stood, with a foot across the two revolvers, while he frantically tried to squeeze his wrists from the handcuffs.

"Steady there! Steady!" cried Silk. "What's your game?" He gave him a shove backward, took up his own revolver, slipped it into his holster, and then flung the other away.

"So?" objected Roche. "You refuse me even de satisfaction for shoot myself? You leave me here, handcuffed, for de flames?" He made a step forward. "Pardon," he said, "but will you not do me de favour for shoot me yourself? It is more queek, less 'orrible. And for your revenge it is all de same. I die anyway. What?"

Silk was not listening to him. He glanced round apprehensively as a shower of black dust and smouldering gra.s.s blades fell from the midst of the heavy pall of rolling smoke. Then he stretched out his hands and caught hold of his prisoner in his strong arms, lifted him bodily, and flung him across the mare's back, holding him there while he seized the reins, raised a foot to the stirrup, and leapt up behind him.

"Go!" he cried, when his seat was secure. "Go, my beauty!"

With a snort and a shake of her mane the mare went forward, dashed up the slope, gained the level, and plunged off with a long, racing stride to mingle with the panic-stricken crowd of bellowing, screeching creatures of the prairie in the mad stampede for escape.

Mile after mile she galloped with her double burden, making never a pause or a break, while the fire, with its terrible crackle and moaning, came closer and closer, and the blinding, choking reek swept by in a thickening cloud.

Silk had no need to use spur or reins. He let her go her own instinctive way, and only strove to keep his awkward seat in the saddle and to hold grimly, desperately to the man lying helpless across his knees. Once only he tightened the reins to check the mare's headlong flight as they came to the brink of a creek. Then, with coaxing, affectionate words, he bade her go warily, guiding her through the shallows, where a struggling crowd of coyotes, rabbits, and prairie dogs wallowed or swam or sank exhausted.

At the farther side of the sluggish stream Silk dismounted, trusting that the fire would not yet leap the water.

"Reckon we can take breath for a while," he said to his moaning prisoner. "Say, I'll just fix you in a more comfortable position and give you a drink. Guess you're needing it. I'd take the handcuffs off you, only I'm afraid you can hardly be trusted, even now. What do you say?"

As he brought a hatful of water and held it up, the half-breed dipped his face in it, and then looked down at him appealingly.

"Sergeant," he pleaded, leaning over and holding out his swollen hands and exhibiting the bruised wrists, "you tek dem off. You 'ave pity, eh?"

Silk shook his head and emptied his hat upon the mare's face.

"Do you think you deserve so much pity?" he asked. "If I took them off you'd only try to escape."

Pierre Roche drew back his hands and awkwardly moved his body as if he meant to slip to the ground.

Silk stopped him.

"Stay where you are," he ordered sternly. "What are you up to?"

"I go no more," returned the half-breed. "I was coward. I no deserve any pity. It ees true. Listen, Sergeant. You was de mos' brave man I ever know. It ees not good you reesk you good life for me any longer. You leave me. You go on alone. I remain. I die. I gif myself to de flame. It ees bes' you go alone, see?"

Sergeant Silk recognised that the man was sincere in his curious entreaty to be left to his fate.

But he shook his head gravely.

"No," he responded. "I must do my duty. I cannot go without my prisoner, and, though you were the worst sinner that ever breathed, I could not bring myself to abandon you to _that_!"

He nodded in the direction of the fiercely advancing flames. A spark nipped his cheek. Round about him he saw tiny jets of smoke rising from among the dry herbage.

"It's coming," he said. "The water won't stop it. Quick!" he cried.

"Your wrists!" He seized the handcuffs and adroitly whipped them free.

"There!" he nodded, "I trust you, see? You could dash off without me now."

Pierre Roche drew a deep breath of relief. He looked down into the sergeant's eyes.

"Dat is true," he acknowledged. "But I give you my parole. I go wid you.

I am you prisoner. I no try for mek my escape. No. I go to my punishment. Quick! Quick!"

He held out his blue and swollen hands to help the soldier policeman to mount.

The mare sped on again, panting hoa.r.s.ely, snorting, swaying sometimes, but never faltering, never slackening her onward rush, until, at last, she reached safety on a wide stretch of blackened earth, where a previous fire had stripped the prairie.

And late on the following morning Sergeant Silk rode into Canmore and delivered up his prisoner at the barracks.

"Ah!" declared the commandant with satisfaction. "I am glad it was you who arrested the rascal, Sergeant. And single-handed, too. You look some jaded. I hope you have had no difficulties?"

"No, sir," returned Silk, "nothing to speak of."

CHAPTER V

NICK-BY-NIGHT

Percy Rapson discovered the lumbering wagon by the cloud of dust which rose above the pine-trees half-way along the valley. He reined in his broncho and waited on the ridge of the hill until his two companions in the uniform of the North-West Mounted Police should rejoin him.

The loud crack of a teamster's whip had told him that there were strangers on the trail beyond this intervening hill.

"There goes the outfit that made the track we've been following up all the afternoon," he announced, pointing in the direction of the cloud of white dust. "Whose is it, I wonder?" he questioned, speaking more particularly to the one who wore a triple chevron on the arm of his faded red tunic. "Looks rather unusual, doesn't it, Silk?"

Sergeant Silk drew down the wide brim of his hat, to shield his eyes from the glare of the setting sun, and contemplated the distant vehicle with its white canvas roof and its plodding team of mules.

"I expect it's a party of prospectors going west to the diggings,"