The United States' suspicions had been aroused by the activity of the German wireless plants, but the arm of the law did not remove at once the German operators at certain commercial stations. They were the men who despatched communications to Berlin and to the raiders. Interspersed in commercial messages they sprinkled code phrases, words, numbers, a meaningless and innocent jargon. The daily press bulletin issued to all ships at sea was an especially adaptable vehicle for this practice, as any traveler who has been forced to glean his news from one of these bulletins will readily appreciate. There were Americans shrewd enough, however, to become exceedingly suspicious of this superficially careless sending, and their suspicions were confirmed through the invention of another shrewd American, Charles E. Apgar. He combined the principles of the phonograph and the wireless in such a way as to record on a wax disc the dots and dashes of the message, precisely as it came through the receiver. The records could be studied and analyzed at leisure. And the United States government has studied them. At three o'clock every morning, the great wireless station at Nauen, near Berlin, uttered a hash of language into the ether. It was apparently not directed to any one in particular, nor did it contain any known coherence. Unless the operator in America wore a DeForest audian detector, which picks up waves from a great distance, he could not have heard it, and certainly during the early part of the war he paid no attention to it. The United States decided, however, that it might be well to eavesdrop, and so for over two years every utterance from Nauen was transcribed and filed away, or run off on the phonograph, in the hope that repetition might reveal the code. Until the code was discovered elsewhere, the phonographic records told no tales, but then the State Department found that it had a priceless library of Prussian impudence. The diplomatic code was a dictionary, its pages designated by serial letters, its words by serial numbers. Thus the message "12-B-15-C-7" signified the twelfth and fifteenth words on the second page, and the seventh word on the third page. This particular dictionary was one of a rare edition. To complement the diplomatic code the Deutches Bank, the German Foreign Office, and their commercial representatives, Hugo Schmidt and Dr. Albert, had agreed upon an arbitrary code which proved one of the most difficult which the American authorities have ever had to decipher. Solution would have been impossible without some of the straight English or German confirmations which followed by mail, but as most of these documents were lost or destroyed, the deciphering had to be done by astute construction of testimony taken from Schmidt as late as the fall of 1917. He had made the work doubly difficult by burning the cipher key and most of his important papers in the furnace of the German Club.