With that he rose to his feet, grasped the lowermost of the barbed wires, and held it up as high as the tension would allow. The quick-witted American understood, and, throwing himself flat on the ground, crawled under the formidable fence. In turn he performed a like service for the Sub, and the two adventurers found themselves within an entanglement out of which they could not easily escape should their presence be detected by any of the sentries.
While negotiating the fence Hamerton noticed one remarkable thing: the standards supporting the spiked wires were set in hinged sockets. Also, about five feet from the fence lay several half-rounded pieces of metal, each about ten feet in length.
"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."