Readers of our previous volumes are now well acquainted with these young men and their friends.  In “The Submarine Boys on Duty” was told how Jack and Hal came to Dunhaven at just the right moment, as it happened, to edge their way into the employ of Jacob Farnum, the young shipbuilder, who was then engaged in the construction of the first of those famous submarine torpedo craft.  The first boat was named the “Pollard,” after David Pollard, the inventor of the craft and of its successors.  By the time that the “Pollard” was ready for launching Jack and Hal had made themselves so valuable to their employer that the boys were allowed to take to the water with the boat when it left the stocks.  Eph Somers, freckle-faced and sunny aired, was a Dunhaven boy who had fairly won his way aboard the same craft by his many sided ability.  Yet, under the direction of Messrs. Farnum and Pollard these youngsters so rapidly acquired the difficult knack of handling submarine boats that they remained aboard.  In the end Jack Benson became the recognized captain of the boat.  Some notable cruises were made, in which the great value of the Pollard type of submarines was splendidly proved, thanks largely to the cleverness of the boys who handled her.

The “Pollard” was present during naval manoeuvres of a fleet of United States warships.  Captain Jack conceived and carried out a most laughable trick against one of the battleships, which attracted public attention generally to this new craft.

In the second volume of the series, “The Submarine Boys’ Trial Trip,” our readers found the young men engaged in giving further and much more startling demonstration to naval officers of the full value of the Pollard type of boat.  Incidentally, it was told how a grasping financier attempted to get control of the Farnum shipyard and its submarine business, with a series of startling plots that the submarine boys were instrumental in balking.  The submarine boat itself passed some of the severest trials that could be invented, yet the trials through which the builders and the submarine boys passed were far greater.  Yet, in the end, just as Mr. Farnum and his associates were about to go to the wall, financially, the Navy Department purchased and paid for the “Pollard.”  In this volume was also told how Jack and his friends were the first to discover a simple, yet seemingly mysterious, method of leaving and entering a submarine boat at will when it lay on the bottom of the ocean.

Then, in “The Submarine Boys and the Middies,” was related how Captain Jack and his chums secured the prize detail of going to Annapolis with the company’s new boat, the “Farnum,” there to teach the midshipmen of the Naval Academy how to operate boats of this class.  That narrative was unusually full of adventures, including the laughable recital of how Eph innocently brought down upon the trio a first-class sample of hazing by Uncle Sam’s naval cadets.  Captain Jack had many startling adventures with the secret agent of a rival submarine company, who sought to discredit and disgrace the young commander of the submarine boys.