In various parts of their country they had been spending their recent vacations together.  The list of books given at the beginning of this story will indicate the various parts of the country in which they had met their adventures.

At the present time, however, when this story opens, they were nearly two thousand miles from home.

Across the continent they had journeyed together and together also they had spent ten days viewing the wonders of the Grand Canyon of the Colorado.  The apparently perilous ride on the backs of donkeys down Bright Angel Trail had been greatly enjoyed, as well as certain other inspiring expeditions which the boys had made, sometimes in company with others and sometimes with a single guide for the quartet.

So enthusiastic had the young travelers become over their experiences that at last they had obtained the consent of their parents to make an expedition of their own.  Two guides were secured who were familiar with the entire region and two strong skiffs were purchased.  In these boats the boys had planned to follow a part of the dangerous Colorado River.  They had no desire to incur the perils that belonged to many of its swirling rapids and tossing waters.  In other places, however, the river was comparatively safe and there the boys planned to follow the course of the stream with their strong and heavy little boats.

Inasmuch as Fred’s father was a prominent railway official he had obtained for the boys certain privileges which otherwise they might not have had.  Fred himself was the most enthusiastic member of the party.  Shorter than any of his comrades his weight was still nearly as great as any of the four.  His solid, sturdy little frame was capable of great endurance and there were few experiences he enjoyed more than tiring his long, lanky comrade John, who as one of his friends brutally expressed it was as much too tall as Fred was too short.

Out of consideration for Fred’s physique, among his friends he was known as Pigmy and Pee Wee, the former title sometimes being shortened into Pyg.

John, however, rejoiced in his name, or if he did not rejoice, at least was accustomed to respond to the appellation, String.

The remaining members of the little band were George Washington Sanders, one of the most popular boys in the school in which all four were students.  Frequently he was referred to as Pop, a distinction by which his friends indirectly expressed their admiration for one who was laughingly referred to as the “Papa of his Land,” just as the great man for whom he was named was the “Father of his Country.”

Grant was the member of the Go Ahead Boys who easily led in whatever he attempted.  In the hundred yards dash he had established the record of the school.  His standing in scholarship was high, while his fund of general information was so extensive that he had received the appellation, Socrates.  This nickname, however, recently had been shortened by the time-saving lads and Grant was more frequently called Soc than by the name which his parents had given him.  His ability as an athlete was scarcely less than his success in the classroom.  And yet Grant by no means was one who withdrew from out-of-door life, or enjoyed less than his friends the stirring adventures in which they all had shared.