Later on he looked in at the club and saw Freddy Vavasour, polo team captain, dawdling over grilled bone No. 1.

“Dear old boy,” began Van Sweller; but in an instant I had seized him by the collar and dragged him aside with the scantiest courtesy.

“For heaven’s sake talk like a man,” I said, sternly.  “Do you think it is manly to use those mushy and inane forms of address?  That man is neither dear nor old nor a boy.”

To my surprise Van Sweller turned upon me a look of frank pleasure.

“I am glad to hear you say that,” he said, heartily.  “I used those words because I have been forced to say them so often.  They really are contemptible.  Thanks for correcting me, dear old boy.”

Still I must admit that Van Sweller’s conduct in the park that morning was almost without flaw.  The courage, the dash, the modesty, the skill, and fidelity that he displayed atoned for everything.

This is the way the story runs.  Van Sweller has been a gentleman member of the “Rugged Riders,” the company that made a war with a foreign country famous.  Among his comrades was Lawrence O’Roon, a man whom Van Sweller liked.  A strange thing—­and a hazardous one in fiction—­was that Van Sweller and O’Roon resembled each other mightily in face, form, and general appearance.  After the war Van Sweller pulled wires, and O’Roon was made a mounted policeman.

Now, one night in New York there are commemorations and libations by old comrades, and in the morning, Mounted Policeman O’Roon, unused to potent liquids—­another premise hazardous in fiction—­finds the earth bucking and bounding like a bronco, with no stirrup into which he may insert foot and save his honor and his badge.

Noblesse oblige? Surely.  So out along the driveways and bridle paths trots Hudson Van Sweller in the uniform of his incapacitated comrade, as like unto him as one French pea is unto a petit pois.

It is, of course, jolly larks for Van Sweller, who has wealth and social position enough for him to masquerade safely even as a police commissioner doing his duty, if he wished to do so.  But society, not given to scanning the countenances of mounted policemen, sees nothing unusual in the officer on the beat.

And then comes the runaway.

That is a fine scene—­the swaying victoria, the impetuous, daft horses plunging through the line of scattering vehicles, the driver stupidly holding his broken reins, and the ivory-white face of Amy Ffolliott, as she clings desperately with each slender hand.  Fear has come and gone:  it has left her expression pensive and just a little pleading, for life is not so bitter.

And then the clatter and swoop of Mounted Policeman Van Sweller!  Oh, it was—­but the story has not yet been printed.  When it is you shall learn bow he sent his bay like a bullet after the imperilled victoria.  A Crichton, a Croesus, and a Centaur in one, he hurls the invincible combination into the chase.