"Stop her!" he ordered.
Leslie obeyed instantly. Although anxious to know the reason of his chief's apparent eccentricity, he refrained from asking questions.
"Get out a coil of two-inch rope, Guy," said Ranworth. "Unless I am much mistaken, there is rotten ice ahead. It wants testing badly."
Guy produced the rope. Making a bowline at one end, Ranworth slipped the loop over his head and shoulders.
"Now," he continued, "I want all hands to pay this out. Keep a slight strain upon it, and, if I shout, haul away instantly."
Having repeated the instructions in French to Petrovitch, Ranworth began to walk towards the supposedly dangerous ground, its position denoted by a difference in colour and a decided dip. North-west and south-east, as far as the eye could see, these characteristics were apparent. To avoid the suspected danger, a long detour would be necessary.
Ranworth proceeded slowly, probing the ground with a crowbar. Once or twice he stopped and prodded vigorously, until, satisfied that the ice was capable of bearing a tremendous weight, he resumed his way.
"The rope's all paid out, sir," reported Guy.
"Very good, you can come this way for another fifty yards. It's sound enough," was the reply.
Just then Ranworth gave a warning shout, but before the three helpers could haul in the slack they saw to their horror the ice giving way all around their isolated comrade.