Now, on this brilliant Saturday morning, as we wait expectant of the signal "Boots and saddles," the cavalcade of our fierce allies comes spattering and plunging through the stream. Grim old chieftains, with knees hunched up on their ponies' withers, strapping young bucks bedaubed in yellow paint and red, blanketted and busy squaws scurrying around herding the spare ponies, driving the pack animals, "toting" the young, doing all the work in fact. We have hired these hereditary enemies of the Sioux as our savage auxiliaries, "regardless of expense," and now, as they ride along the line, and our irrepressible Mulligans and Flahertys swarm to the fore intent on losing no opportunity for fun and chaff, and the "big Indians" in the lead come grinning and nodding salutations towards the group of officers at headquarters, a general laugh breaks out, for nearly every warrior has decorated himself with a miniature signal flag. Fluttering at the end of his "coup" stick or stuck in his headgear, a small square of white towelling or flour-sack, with a centre daub of red paint, is displayed to the breeze, and, under his new ensign, Mr. Lo rides complacently along, convinced that he has entered upon his campaign with "good medicine." Half-past six. Still no signal to bring in the herds. But Merritt, Carr, and Royall are born and bred cavalrymen, and well know the value of every mouthful of the rich dew-laden grass before the march begins. We are exchanging good-byes with the quartermasters and the unhappy creatures who are to remain behind, adding our closing messages to the letters we leave for dear ones in distant homes, when the cheery notes ring out from brigade headquarters and are taken up, repeated along the line by the regimental trumpeters. Far out on the slopes our horses answer with eager hoof and neigh; with springy steps the men hasten out to bridle their steeds, and, vaulting on their backs, ride in by companies to the line. The bustle of saddling, the snap of buckle and whip of cinch, succeeds, then "Lead into line" is heard from the sergeant's lips. Officers ride slowly along their commands, carefully scrutinizing each horse and man. Blanket, poncho, overcoat, side-line, lariat, and picket-pin, canteen and haversack, each has its appropriate place and must be in no other. Each trooper in turn displays his "thimble belt" and extra pocket package, to show that he has the prescribed one hundred rounds. The adjutant, riding along the line, receives the report of each captain and transfers it to his note-book. Away down the valley we see the Second and Third already in motion, filing off around the bluffs. Then General Carr's chief trumpeter raises his clarion to his lips. "Mount," rings out upon the air, and with the sound twenty officers and five hundred and fifteen men swing into saddle. Ten minutes more and we are winding across the divide towards Prairie Dog Creek on the east. The Third and Second, a mile to our left,