And then Silas Bannerman, a secret service agent of the United States, leaped into world-fame by arresting Emil Gluck.  At first Bannerman was laughed at, but he had prepared his case well, and in a few weeks the most sceptical were convinced of Emil Gluck’s guilt.  The one thing, however, that Silas Bannerman never succeeded in explaining, even to his own satisfaction, was how first he came to connect Gluck with the atrocious crimes.  It is true, Bannerman was in Vallejo, on secret government business, at the time of the destruction of Mare Island; and it is true that on the streets of Vallejo Emil Gluck was pointed out to him as a queer crank; but no impression was made at the time.  It was not until afterward, when on a vacation in the Rocky Mountains and when reading the first published reports of the destruction along the Atlantic Coast, that suddenly Bannerman thought of Emil Gluck.  And on the instant there flashed into his mind the connection between Gluck and the destruction.  It was only an hypothesis, but it was sufficient.  The great thing was the conception of the hypothesis, in itself an act of unconscious cerebration—­a thing as unaccountable as the flashing, for instance, into Newton’s mind of the principle of gravitation.

The rest was easy.  Where was Gluck at the time of the destruction along the Atlantic sea-board? was the question that formed in Bannerman’s mind.  By his own request he was put upon the case.  In no time he ascertained that Gluck had himself been up and down the Atlantic Coast in the late fall of 1940.  Also he ascertained that Gluck had been in New York City during the epidemic of the shooting of police officers.  Where was Gluck now? was Bannerman’s next query.  And, as if in answer, came the wholesale destruction along the Mediterranean.  Gluck had sailed for Europe a month before—­ Bannerman knew that.  It was not necessary for Bannerman to go to Europe.  By means of cable messages and the co-operation of the European secret services, he traced Gluck’s course along the Mediterranean and found that in every instance it coincided with the blowing up of coast defences and ships.  Also, he learned that Gluck had just sailed on the Green Star liner Plutonic for the United States.

The case was complete in Bannerman’s mind, though in the interval of waiting he worked up the details.  In this he was ably assisted by George Brown, an operator employed by the Wood’s System of Wireless Telegraphy.  When the Plutonic arrived off Sandy Hook she was boarded by Bannerman from a Government tug, and Emil Gluck was made a prisoner.  The trial and the confession followed.  In the confession Gluck professed regret only for one thing, namely, that he had taken his time.  As he said, had he dreamed that he was ever to be discovered he would have worked more rapidly and accomplished a thousand times the destruction he did.  His secret died with him, though it is now known that the French Government