"Flashes in the night," answered Callahan. "I noticed that an electric sign wasn't behaving regularly--so I jotted down its signals and passed them on to you. The next important point is whether the message is complete enough for you to reconstruct the code. Have you got all the letters?" "Yes, every one of them." "Then take down this message, put it into that dot-and-dash code and send it to me by special messenger on one of the navy torpedo boats to-night. It's a matter of life and death to thousands of men!" and Callahan dictated three sentences over the wire. "Got that?" he inquired. "Good! Get busy and hurry it down. I've got to have it in the morning." "Turn around," he directed the Mexican, as he replaced the receiver. "Were you to send these messages only on Saturday night?" "_Si, senor._ Save that I was told that there might be occasions when I had to do the same thing on Sunday night, too." "At nine o'clock?" "_Si, senor._" Callahan smiled. Things were breaking better than he had dared hope. It meant that the U-boat would be watching for the signal the following night. Then, with proper emphasis of the automatic, he gave the Mexican his orders. He was to return to his office with Callahan and go about his business as usual, with the certainty that if he tried any foolishness the revolver could act more quickly than he. Accompanied by the government agent, he was to come back to the Monticello and spend the night in Callahan's room, remaining there until the next evening when he would--promptly at nine o'clock and under the direction of an expert in telegraphy--send the message which Callahan would hand him. That's practically all there is to the story. * * * * * "All?" I echoed, when Quinn paused. "What do you mean, 'all'? What was the message Callahan sent? What happened to the Mexican? Who sent the letter and the money from Washington?" "Nothing much happened to the Mexican," replied my informant, with a smile. "They found that he was telling the truth, so they just sent him over the border with instructions not to show himself north of the Rio Grande. As for the letter--that took the Post Office, the Department of Justice, and the Secret Service the better part of three months to trace. But they finally located the sender, two weeks after she (yes, it was a woman, and a darned pretty one at that) had made her getaway. I understand they got her in England and sentenced her to penal servitude for some twenty years or more. In spite of the war, the Anglo-Saxon race hasn't completely overcome its prejudice against the death penalty for women." "But the message Callahan sent?" I persisted. "That was short and to the point. As I recall it, it ran something like this: 'Urgent--Route of _America_ changed. She clears at daylight, but takes a course exactly ten miles south of one previously stated. Be there."