out rather late. Hi, hansom!"

And he bundled me into a cab, and took my name and address, and the next
moment I was bowling along on my road to St. John's Wood.

It was nearly six in the morning when I arrived, and, fortunately, no
one heard me when I let myself in with my latch-key.

My wife thought I had only been sitting up extra late at my work, and I
told her nothing of my night's adventure. But I summoned two able-bodied
detectives to my aid, and they agreed to await with me the lunatic's
second visit. My family supposed that the detectives had come to assist
me in getting up a tale of crime, and I did not undeceive them. So I
despatched them to bed at an earlier hour than usual, on the plea that I
did not wish to be disturbed, and sat with my companions in the study
watching for the madman.

[Illustration: "YOU HAD BETTER GO HOME QUIETLY, SIR."]

Precisely at ten o'clock there was heard a heavy footstep on the gravel
path without, and once more a knock--a single knock.

"He has come," we whispered.

We had duly arranged our "plan of campaign," and now proceeded to carry
it out. The most stalwart of the detectives was to open the front door,
and the other to hide behind it. My post was on the threshold of my
study, where I was to stand as a "reserve."

The men were wonderfully prompt in executing their operations. The
street door had hardly been opened when there was a scuffle and a heavy
fall, accompanied by much growling and cursing, and then the
unmistakable sound of the snapping of a pair of handcuffs.

"It's all right," said the detective who had been behind the door, "we
have got him and his six-shooter too."

Whereupon he produced the very weapon with which the maniac had
threatened me--the large, bright, new revolver. I identified it at once.

"I got it out of his side pocket quick as thought," said the man.

Good! And now I retired into my study while the other detective brought
the stranger forward.

"What the devil are you fools about?" I heard him cry, as he entered,
handcuffed, at the door.

The sound of his voice startled me. It was _not_ that of my visitor the
night before. A single glance showed me that it was quite a different
sort of person.

"Halloa!" I cried, "there is some mistake here. That's not the lunatic."

"Lunatic!" exclaimed the captured man, "I should think not indeed. It is
you who are the lunatics. I am a policeman!"

And a policeman he was--in plain clothes. He