“Say, feller, who do you think is making this arrest?  You’ll go to the station-house when I get ready.”

“Then you’re ready now,” snapped the criminologist.  “You’ll see me discharged very promptly, when I speak to the Commissioner over the wire.”

The officer was supercilious until the station-house was reached.  He had heard this blatant talk before.  What was his surprise when Shirley telephoned to the head of the Department and then called the Captain to the instrument.

“Release Mr. Shirley at once,” was the crisp order.  “Give him any men or assistance he needs.”

“Well, whadd’ye know about that?  Not even entered on the blotter to credit me with a good arrest!” The patrolman turned away in disgust.

“Do you want any of the reserves, sir?” The Captain was scrupulously polite.

“Not one.  I’m going to study that machine again.  You might detail a plain clothes man to walk along the other side of the street for luck.  Good-day.”

The automobile to which he returned was still the object of community interest.  Shirley took the remains of the bomb which had caused his sudden elevation.  The policeman approached him from the fruit store.

“The man wants damages for the stock you destroyed, mister.  I’ll fix it up with him if you want—­about twenty-five dollars will do.”

“Well, hand him this five-dollar bill and see if that won’t dry some of the imported tears,” retorted Shirley with a laugh.  In a few minutes he was bowling along on a surface car, to the club.  There was no longer any use in trying to hide his identity or address, for the conspirators knew at least of his interest and assistance in the case:  although in this as all others he was not known to be a professional sleuth.

In the quiet of his room he drew out magnifying glasses and other instruments for a thorough analysis of the remains of the infernal machine.  He compared this with the mechanism of the gas-generator which had been placed in the seat of the Death taxi.  There was evidence that it had come from the same source.  Shirley sniffed at the generator and the peculiar odor still clinging to it was familiar.

“Well, I think I will have a little surprise for Mr. Voice, the next time we grapple, which will be an encore of his own tune, with a new verse!”

He went to a cabinet, took out a small glass vial, filled with a limpid liquid and placed it within his own pocket.  Then he prepared for a new line of activities for the day.  His first duty was a call on Pat Cleary, superintendent of the Holland Agency.

“The Captain is progressing splendidly,” was his answer to the anxious query.  “He will be back in the harness again to-morrow.  How are the prisoners?”

“They have tried to break out twice and gave my doorman a black eye.  But they got four in return:  Nick is no mollycoddle, you know.  I can’t quite get the number of these fellows, for they are not registered down at Headquarters, in the Rogue’s Gallery.  Their finger-prints are new ones in this district, too.  They look like imported birds, Mr. Shirley.  What do you think?”