All along under the cottonwoods below the crossing the bivouac extends.  Long before sunrise these hardy fellows were in saddle and, in long column, have come marching down from the north,—­four strong troops,—­a typical battalion of regular cavalry as they looked and rode in those stirring days that brought about the subjugation of the Sioux.  Out on the prairie the four herds of the four different troops are quietly grazing, each herd watched by its trio of alert, though often apparently dozing, guards.  One troop is made up entirely of black horses, another of sorrels,—­two are of bays.  Another herd is grazing close to the stream,—­the mules of the wagon-train, and the white tops of these cumbrous vehicles are dotting the left bank of the winding water for two or three hundred yards.  Cook-fires are smouldering in little pits dug in the yielding soil, but the cooking is over for the present; the men have had their substantial dinner and are now smoking or sleeping or chatting in groups in the shade,—­all but a squad of a dozen, commanded by a grizzled veteran on whose worn blouse the chevrons of a first sergeant are stitched.  Booted and spurred, with carbines slung and saddles packed, these sun-tanned fellows are standing or sitting at ease, holding the reins of their sleepy chargers and waiting apparently for the passengers who are to start in the stout-built “Concord” drawn by four sleek, strong-looking mules, now standing in the shade near the canvas homestead of the commanding officer.

Presently two soldiers following a young man in civilian dress come forward lugging a little green painted iron safe, and this, with a swing and a thud, they deposit in the wagon.

“You’ve seen that before, sergeant,” laughs the civilian.

“I have, begad, an’ when it had a heap more green inside an’ less outside than it has now.  Faith, I never expected to see it again, nor the paymaster either.  We were both bored through and through.  ’Twas our good habits that saved us.  Sure your predecessor was a game fighter, Mr. Barnes, if he was a tenderfoot.”

“Yes, the major often tells me he wishes he had him back, and me in the place he has instead of the one he had,” answers the clerk, whimsically.  “Does he know you’re to command the escort in?  You got him into such a scrape then that he’s never tired of telling of it.”

“Then he may feel gratified at the honor I am doing him now.  Sure it’s beneath the dignity of a first sergeant to command a squad like this except on extraordinary occasion, and it’s to take the taste of the last time out of his mouth I volunteered to escort the major now.  ’Twas a strong taste to last five years, though my reminder will go with me many a year longer.  Here they come now.”

As the sergeant speaks a little group of officers issues from the battalion commander’s tent.  Foremost among them, in loose flapping raiment and broad-brimmed hat and green goggles, the rotund and portly shape of Major Plummer, the paymaster.