Sunday came at last, with its welcome relief from toil. They lay late in bed that morning, making up lost rest, revelling in the unaccustomed luxury of leisure, and in the afternoon Jack took the boy for a tour through the shops, swarming with busy life on week-days, but now deserted, save for an occasional watchman. And here Allan got, for the first time, a glimpse of one great department of a railroad’s management which most people know nothing of. In the first great room, the “long shop,” half a dozen disabled engines were hoisted on trucks and were being rebuilt. Back of this was the foundry, where all the needed castings were made, from the tiniest bolt to the massive frame upon which the engine-boiler rests. Then there was the blacksmith shop, with its score of forges and great steam-hammer, that could deliver a blow of many tons; and next to this the lathe-room, where the castings from the foundry were shaved and planed and polished to exactly the required size and shape; and still farther on was the carpenter shop, with its maze of woodworking machinery, most wonderful of all, in its nearly human intelligence. Beyond the shop was the great coal chute, where the tender of an engine could be heaped high with coal in an instant by simply pulling a lever; then the big water-tanks, high in air, filled with water pumped from the river half a mile away; and last of all, the sand-house, where the sand-boxes of the engines were carefully replenished before each trip. How many lives had been saved by that simple device, which enabled the wheels to grip the track and stop the train! How many might be sacrificed if, at a critical moment, the sand-box of the engine happened to be empty! It was a startling reflection—that even upon this little cog in the great machine—this thoughtless boy, who poured the sand into the boxes—so much depended. Bright and early Monday morning they were out again on Twenty-one. Wednesday was inspection, and they knew that up and down those two hundred miles of track hand-cars were flying back and forth, and every inch of the roadway was being examined by eyes severely critical. They found many things to do, things which Allan would never have thought of, but which appealed at once to the anxious eyes of the foreman. About the middle of the afternoon, Welsh saw a figure emerge from a grove of trees beside the road and come slouching toward him. As it drew nearer, he recognized Dan Nolan. “Mister Welsh,” began Nolan, quite humbly, “can’t y’ give me a place on th’ gang ag’in?” “No,” said Jack, curtly, “I can’t. Th’ gang’s full.” “That there kid’s no account,” protested Nolan, with a venomous glance at Allan. “I’ll take his place.” “No, you won’t, Dan Nolan!” retorted Jack. “He’s a better man than you are, any day.” “He is, is he?” sneered Nolan. “We’ll see about that!”