"Yes, sir. I marked the direction on the blotter beneath the detector."
"We'll take a look at it," said the leader, and the little band entered the wireless room, where Lew was now on duty.
On the white blotter they found a long black line, tipped with an angle mark like an arrow-head. Captain Hardy got a map of the city, and spreading it on the table true to the compass points, stretched a yardstick across it in the direction indicated by the arrow.
"Hoboken," he muttered. "The arrow points to Hoboken." For a moment he studied the map before him. "You will remember," he said, looking up, "that Hoboken is the point on the Jersey side of the Hudson where there are such great railroad freight yards and such huge piers. Many Atlantic liners sail from Hoboken. Evidently the Germans are watching there. Of course they would be. Their spies are informing other German agents every time a troop ship sails. And somehow they get that news to Germany. It's a terrible menace to our army, boys. We must put an end to it."
"We will," came the reply from four sober-faced boys.
"It's going to be a long task, boys," said Captain Hardy. "Get your hats and we'll take a look at Hoboken."
Leaving Lew at the wireless, the four others set out. They rode for a distance on a Ninth Avenue elevated train, then walked to the ferry, and in less than an hour of the time they left their headquarters found themselves in the great Jersey shipping point.
Never had the boys from Central City seen anything quite like the water-front at Hoboken. The level ground was one great maze of railroad tracks, freight depots, warehouses, and pier sheds. The wide thoroughfare running along the waterfront presented a scene of bewildering confusion. Trolley-cars, steam trains, motor trucks, horse-drawn vehicles, and other conveyances were moving this way and that. Whistles were tooting, motors honking, bells ringing, drivers swearing, policemen shouting orders. Pedestrians were dodging in and out, messenger boys were darting here and there. Porters were carrying bundles on their shoulders, laborers were wheeling materials in steel wheelbarrows, lines of heavily laden trucks were passing into steamship piers, and guards and watchmen at every entrance were closely scrutinizing all who approached.
The four observers walked slowly along, studying every foot of the way. High fences had been built here and there to hide what was going on behind them. Covered ways led from railway terminals to pier sheds so that none could see what had come by train. Even the gangways to the ships were screened. Every precaution had been taken to baffle curious eyes.
"They've done their best," commented Captain Hardy, "but they can't screen a ship on the river, and the Germans know when our transports sail, even if they don't know what's in them. Any one with a good glass can look out from any house along the river front and see clearly every move made by a steamer. Let's take a stroll among these houses."