I'm working in the dark on a case that I'm not even positive exists. That infernal submarine may be laying off Boston at this minute, waiting for the ship that leaves there Tuesday. Maybe they don't get any word from shore at all.... Maybe they just...."[9]But here he was brought up with a sudden jar that concentrated all his mental faculties along an entirely different road.
Gazing out over the lights of the city, scarcely aware that he saw them, his subconscious mind had been following for the past three minutes something apparently usual, but in reality entirely out of the ordinary.
"By George!" he muttered, "I wonder...."
Then, taking his watch from his pocket, his eyes alternated between a point several blocks distant--a point over the roofs of the houses--and the second hand of his timepiece. Less than a minute elapsed before he reached for a pencil and commenced to jot down dots and dashes on the back of an envelope. When, a quarter of an hour later, he found that the dashes had become mo-
4
notonous--as he expected they would--he reached for the telephone and asked to be connected with the private wire of the Navy
Department in Washington.
"Let me speak to Mr. Thurber at once," he directed. "Operative Callahan, S. S., speaking.... Hello! that you, Thurber?... This is Callahan. I'm in Norfolk and I want to know whether you can read this code. You can figure it out if anybody can. Ready?... Dash, dash, dash, dot, dash, dash, dot--" and he continued until he had repeated the entire series of symbols that he had plucked out of the night.
"Sounds like a variation of the International Morse," came the comment from the other end of the wire--from Thurber, librarian of the Navy Department and one of the leading American authorities on code and ciphers. "May take a little time to figure it out, but it doesn't look difficult. Where can I reach you?"
"I'm at the Monticello--name of Robert P. Oliver. Put in a call for me as soon as you see the light on it. I've[10] got something
important to do right now," and he hung up without another word.
A quick grab for his hat, a pat under his arm, to make sure that the holster holding the automatic was in place, and Callahan was on
his way downstairs.
Once in the street, he quickened his pace and was soon gazing skyward at the corner of two deserted thoroughfares not many blocks from the Monticello. A few minutes' consultation with his watch confirmed his impression that everything was right again and he commenced his search for the night watchman.
"Who," he inquired of that individual, "has charge of the operation of that phonograph sign on the roof ?"
"Doan know fuh certain, suh, but Ah think it's operated by a man down the street a piece. He's got charge of a bunch of them sort o' things. Mighty funny kinder way to earn a livin', Ah calls it--flashing on an' off all night long...."
"But where's he work from?" interrupted Callahan, fearful that the negro's garrulousness might delay him unduly.
"Straight down this street three blocks, suh. Then turn one block to yo' left and yo' cain't miss the place. Electrical Advertisin' Headquarters they calls it. Thank you, suh," and Callahan was gone almost before the watchman could grasp the fact that he held a five-dollar bill instead of a dollar, as he thought.
It didn't take the Secret Service man long to locate the place he sought, and on the top floor he found a dark, swarthy individual bending over the complicated apparatus which operated a number of the electric signs throughout the city. Before the other knew it, Callahan was in the room--his back to the door and his automatic ready for action.[11]
"Up with your hands!" snapped Callahan. "Higher! That's better. Now tell me where you got that information you flashed out to sea to-night by means of that phonograph sign up the street. Quick! I haven't any time to waste."
"Si, si, senor," stammered the man who faced him. "But I understand not the English very well."
"All right," countered Callahan. "Let's try it in Spanish," and he repeated his demands in that language.
Volubly the Spaniard--or Mexican, as he later turned out to be--maintained that he had received no information, nor had he transmitted any. He claimed his only duty was to watch the "drums" which operated the signs mechanically.
"No drum in the world could make that sign flash like it did to-night," Callahan cut in. "For more than fifteen minutes you sent a variation of the Morse code seaward. Come on--I'll give you just one minute to tell me, or I'll bend this gun over your head."
Before the minute had elapsed, the Mexican commenced his confession. He had been paid a hundred dollars a week, he claimed, to flash a certain series of signals every Saturday night, precisely at nine o'clock. The message itself--a series of dots and dashes which he produced from his pocket as evidence of his truthfulness--had reached him on Saturday morning for the two preceding weeks. He didn't know what it meant. All he did was to disconnect the drum which operated the sign and move the switch himself. Payment for each week's work, he stated, was inclosed with the next week's message. Where it came from he didn't know, but the envelope
was postmarked Washington.
With his revolver concealed in his coat pocket, but with its muzzle in the small of the Mexican's back, Callahan[12] marched his cap-
5
tive back to the hotel and up into his room. As he opened the door the telephone rang out, and, ordering the other to stand with his face to the wall in a corner--"and be damn sure not to make a move"--the government agent answered the call. As he expected, it was Thurber.
"The code's a cinch," came the voice over the wire from Washington. "But the message is infernally important. It's in German, and evidently you picked it up about two sentences from the start. The part you gave me states that the transport America, with twelve thousand men aboard, will leave Norfolk at daylight Monday. The route the ship will take is distinctly stated, as is the personnel of her convoy. Where'd you get the message?"
"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."[13]
"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
