"You said I had to!" he replied. The boy's new chief gave a half-smile. "Well," he said, "if you always do everything I say you have to do, I'll be quite satisfied. But it's not a summer picnic, by any means, and you may be sorry before you're through." "That may be, Mr. Rivers," answered the boy cheerily, "but I'm not sorry yet. I'm mighty glad to be here." "I've been sorry often enough that I took up field work, but----" he paused. "But what?" asked Roger. "But I couldn't get back to it quick enough the next year," answered the geologist. "If the past summer is any test," went on Roger, "I guess I'll be the same way, for I never enjoyed anything so much in all my life. Why, I felt quite stifled back in Washington." "If you've been caught with the exploring fever," rejoined the older man, "there's nothing more to be said, for that's a disease for which there is no cure, except----" He paused abruptly again. "Yes?" queried Roger. "Except old age, and that the explorer never reaches," was the steady reply. "And now you must meet the rest of the boys." He turned to the topographer, who was standing near. "Mr. Gersup," he said, "this is the boy." "I see it's a boy," answered the other, smiling, "but I didn't know it was 'the' boy. I guess, Doughty, from the way Mr. Rivers talks, that you're only just a trifle less important in the Survey than the Director." He laughed out loud. Roger broke in protestingly, but Rivers interrupted. "Don't mind him, Doughty, he's always that way." "Don't mind him either, Doughty," replied the topographer, "he's always that way." And Roger thought it promised well for the cheerfulness of the party to find the chief and the topographer on joking terms. Later the boy found Gersup's cheerfulness and optimism to be invaluable on the trip. He had a short, thick-set, stocky frame and possessed to an extreme degree the power of seeing the best possible side of every situation. His persuasive powers were so great that, as one of the party said afterward, "he could talk a mule's heels down in the middle of a kick!" He had an unerring eye for the topography of a country, as was afterwards shown, and before they had been many days in Alaska, Roger would have unhesitatingly declared both the geologist and topographer of the party to be absolutely infallible in their own lines, though they would both promptly have disclaimed any such statement.