"You are excused from further instruction here at this time," the officer announced to the trio. "You will accompany Sergeant Martin for further orders." And they hurried from the room with the non-com., who they instinctively knew was their friend. What was this new experience that lay before them? They were not long in learning, and the information almost carried them beyond the restraints of good discipline and to the indulgence in three ripping good cheers. Sergeant Martin could be a hard taskmaster when it was necessary to be so, but, like the headmaster of Brighton, he did not believe in needless red tape, nor did he delude himself that the stripes upon his sleeve made him a better man--except in official authority--than the one who wore none at all. He realized the curiosity that must be consuming the three lads, and he was not averse to satisfying it. "Selected for service aboard a transport bound for Europe," he announced briefly. "Thank you, sir," said Joe, not entirely able to control the happiness in his voice, while Slim's excess stomach almost entirely disappeared in the abnormal expansion of his chest. Jerry could find no other dignified way of expressing his great pleasure than by quietly poking Slim under the ribs, to the entire undoing of that young man's military attitude. "Do we go at once, sir?" inquired Joe deferentially. "Probably to-morrow evening," said Sergeant Martin, as they arrived at the building housing the captain and staff in charge of men of the Signal Corps then stationed at the navy yard. It was the busiest office the three boys had ever seen. Typewriters were clicking, telegraph instruments were at work, orderlies were hurrying about, and every man in the place was engrossed in his own particular task. Sergeant Martin guided them to an inner office. Here they confronted an austere gentleman whose uniform denoted that he was a captain, and whose whole bearing bespoke military service. The three boys were dumbfounded to learn that he already had their names on a card before him. They were getting a new idea of the efficiency of Uncle Sam's service. The captain made numerous notes as he questioned them about their experience, general knowledge, and extent of their education. He eyed Slim shrewdly as he inquired whether they thought they might be subject to seasickness. "Young men," he said abruptly, "this country is engaged in the greatest war in all history. Considering your youth and present lack of experience, yours is to be a part of great responsibility. You look like capable and courageous young Americans, and I believe you are. I have confidence that you will bear your share of the burdens of war with credit to yourselves and glory to your country. With one other man of more experience, you will be placed in charge of the wireless and other signal apparatus aboard the transport _Everett_, leaving within thirty-six hours. Sergeant Martin will now aid you in procuring your uniforms."