Jim was not near enough to them, when the line halted before the wall and faced about, to notice how they craned their heads around and stared at it. What could they have been thinking about, in or on that gray, stony face? Jim himself had thought of it and had studied it, and it seemed to him to be all the while coming between him and the island wharf. Still, he paid particular attention to his orders and his marching, just as he had, in the earlier part of the day, to his type-setting tasks. The close of the day came, at last, in a dim, foggy kind of dusk that promised darkness much earlier than usual. The parade-ground, and all the rest of the wide enclosure, outside of the buildings, seemed to be deserted. Inside of the buildings, however, there suddenly arose a kind of buzz, that quickly amounted to something like an excitement. A rumor whispered its way around among the boys that three of their number were missing and could not be found. They did not know that the first difficulty which troubled their officers, just then, was that there was not a sufficient number of themselves for indoor duty and, at the same time, to spare searchers for stray boys over so large a space and in so many places. Nearly a score of the older and more trustworthy boys were therefore picked out as helpers, and they were quickly scurrying hither and thither, in all directions. Jim felt especially gratified that the Assistant Superintendent, a handsome young naval officer whom he could not help liking, chose him for one of the hunters. He knew that neither of the fellows were missing whom he intended as the crew of his boat, and he went out into the dim, gloomy parade-ground with a perfect fever of curiosity to discover what any other fellows were up to. “They can’t get away,” he said to his blue uniformed friend, “but what can they be trying to do?” “We’ll see,” said the officer, “but we can’t find a trace of them.” It was indeed a pretty long time before they did so. Every nook and cranny of the shops and other buildings and of all the walled-in ground had been gone over and it was, fast getting into the shape of a mystery. Jim was carrying a lantern, but the officer held in his hand a different kind of light, a reflector, a “bull’s-eye,” that would throw a stream of light ahead like a small locomotive headlight. He was busily throwing it in all directions and just now, as if by mere accident, he sent it up to the roof of the large building next to the engine building. It was not so very high, but was much higher than the latter and it had several chimneys, coming out just above its eaves. “Hullo!” exclaimed Jim. “There they are!” said the officer, almost laughing; and then he shouted, commandingly: “Come down, boys! We’ll put up a ladder.”