"They are in the habit of lowering the fence for something," said the Sub to himself. "These sections are to place over the wire when it is lying on the ground. Seems as if they take rather fragile objects into the enclosure; which, I wonder?"
"Steady on!" cautioned Detroit. "Here's something."
The something proved to be the stone facing of a steep incline cut into the earth. The investigators had the choice of two routes, either to bear away to the left and follow the natural terrain, or take the right-hand direction and descend the incline. They chose the latter.
The shelving ground was slippery with rain. Close to the concrete wall was a small channel through which the surface water poured in a miniature torrent. Extreme caution was necessary, since at any moment the two comrades might find themselves precipitated over the edge of a pitfall.
"Come this way," said Hamerton in a low voice. "I want to find out the width of this incline." And setting off at right angles to his previous direction he began to measure the distance. At the eightieth pace—equal to one hundred and twenty feet—the adventurers found themselves confronted by a wall similar to the one on the other side of the incline. They had stumbled upon a broad way, leading they knew not whither or for what purpose.
"Keep to this side," continued Hamerton. "It's more sheltered."
"Better not," objected Detroit. "If there are any people about they will naturally choose the lee side of this wall. We can't get much wetter, and we stand a better chance over there."
"Right!" assented the Sub. He was not above paying good heed to the American's sagacity.
Accordingly they retraced their steps to the left wall of the incline and then resumed the downward direction. Higher and higher grew the wall, till it was lost to sight in the darkness. It seemed as if they were descending into the bowels of the earth. Presently both men involuntarily paused. Through the rain-laden atmosphere came a red glare. It only lasted a few seconds and then disappeared.
"A furnace," whispered Hamerton. "Luckily it was not on our side. Ha! what's that?" His feet came into contact with the metal rail of a narrow-gauge tram line, emerging from a cave-like chamber in the wall and running athwart the incline. Further investigations revealed the presence of a siding on which were several trucks laden with coal. The trucks had been filled by means of a number of shoots. Close by, under a lean-to shed, were nearly a hundred barrels, some empty and lying in disorder, and others filled and stacked in tiers.