Rat-a-tat-tat!  Jack hardly comprehended what this new noise meant when it grew in volume.  Then a horseman rode into the yard at a charge.

“One down!” yelled the rider, with savage glee, as he drove his mount squarely against one of the wretches, bowling him over and underfoot.

Hardly seeming to veer, the rider made for another fellow, and barely missed him.

Just a second later, so it seemed, this valiant rider hauled the horse on its haunches, and swung back, heading for another wretch.

Millard leaped at the horseman, a stone in his uplifted fist.

But Jack Benson saw him, and a well-planted blow sent Millard to the ground.

“Bully good of you, Benson, old chap!” called a hearty voice.  Then the horseman spurred forward, running down another of Benson’s late assailants.  The two remaining bolted as fast as they could, go.

“Mr. Abercrombie!” cried Lieutenant Jack.

“Yes, it’s I:  and jolly glad I got here in good time,” laughed the British naval officer, whom this brief rollicking battle had made as gleeful as a boy.

“But how on earth did you happen to turn up?” asked Jack, a feeling of mystery coming over him after he had glanced at Millard and had made sure that the latter would “sleep” for some time to come.

“Why, I was out for my afternoon canter, dear old fellow,” bubbled Lieutenant Abercrombie, R.N.  “I was coming down the road at a hard trot, don’t you know, when a cab rolled by.  A young woman—­and a deuced pretty one—­thrust her head out and shrieked at me.  What could I do?  It was deuced extraordinary, and I had to do something quickly, so I rode alongside the cab and told the driver to hold up.  I must have looked unusually menacing, don’t you know, for, by Jove, the fellow obeyed me.  Then I reached up and yanked him down off the cab.  The fellow really started to blackguard me, while the young woman was shouting something at me at the same time I had to silence the fellow, don’t you know, so I could understand the young lady.  So I struck him over the head with the butt of my riding whip.  My word, I must have hit the blackguard hard, for he just curled up and lay down.  The young lady sprang out of the cab and begged me to hurry down here.  She looked able to take care of herself, so I just left my revolver with her, and, by Jove, here I am—­and deuced glad of it.  Upon my word, Benson, dear old fellow, all the luck seemed to be running against you.”

“It was,” Jack admitted, dryly.  “But now I’ve got the man I came after.  I’ve got to keep him, too,” added Lieutenant Benson, gravely.

As he spoke, the submarine boy drew a pair of handcuffs from an inner pocket.

“By Jove, do naval youngsters in this country carry such jewelry?” murmured Lieutenant Abercrombie, R.N.

“They do, I guess, when they’re engaged on work like mine at present,” smiled Lieutenant Jack, United States Navy.