Adventures enough had befallen the submarine boys to last any man for a lifetime.  Yet, as fate decreed it, Captain Jack Benson and his staunch young comrades were now destined to adventures greater and further reaching than any of which they could have dreamed.  In advance, this winter trip to Spruce Beach promised to be little more than a pleasant relaxation for the youngsters.  What it really turned out to be will soon be made clear in the pages of this volume.

“It seems a very risky plan that you’re trying, Jack,” remarked Jacob Farnum, at last.

“Don’t you want me to do it, sir?” asked the young skipper, looking up instantly from his chart.

“Why, er—­”

But here David Pollard, the inventor of these boats broke in, eagerly: 

“Of course we ought to do it, Farnum.  Jack is wholly right.  If we enter the harbor at Spruce Beach in this fashion, and carry through our entire plan successfully, what on earth can there be left for opponents of our class of boats to say?”

“Not if we succeed, of course,” smiled Farnum.  “It’s only the pesky little ‘if’ that’s bothering me at all.  I don’t want any of you to think me a coward—­”

“We know, very well, you’re not, sir,” Captain Jack interposed, very quietly.

“But if we make any slip in our calculations,” continued Jacob Farnum, “the first bad thing about it is that we’ll smash a fine boat which, otherwise, the United States Government is likely to want at a price around two hundred thousand dollars.  That, however, is not the greatest risk that I have in mind.  On board this craft are five people without whom it would be rather hopeless for anyone to go on building the Pollard type of boat.  Therefore, besides risking a valuable craft and our own rather inconsequential lives, we go further and put the United States Navy in danger of having only a couple of our boats.  Now, the fact is, we want the Navy to have three or four dozen of our submarine craft, for we ourselves believe implicitly in the great worth of the Pollard boats.”

“That’s just the point, sir,” cried Captain Jack Benson.

“Eh?  What is?” inquired Mr. Farnum, looking at his young skipper in some bewilderment.

“Why, sir,” laughed Jack, “the point is that we believe our boats to be infinitely ahead of anything owned in any other navy on earth.  We believe it possible to do things, with boats like this one, that can be accomplished with no other submarine craft in the world.  Now, it’s a fact that, in all the navies, lest an accident happen to a submarine, that craft is obliged to travel about, always, in the company of a steam craft of war, which is known as the parent ship.  Yet we’ve come, straight from the shipyard at Dunhaven, many hundreds of miles, without any such escort.  We’ve been running along under our own power, night and day, without accident, stop or bother.  Thus we’ve shown