"Careful!" hissed his companion. "You will be heard over the whole island."
"What matters? There is not another soul in sight besides ourselves. How much petrol have you?"
"Fifty two-gallon tins. I expect some more by boat to-morrow. It's safely stored in a cave on the side of the creek. It is a nuisance it is raining. I do not fancy a night's work in weather like this. Himmel, what's that?"
Accidentally Vernon's foot had dislodged a small piece of stone.
"Nerves, my dear von Ruhle," said Ramblethorne, with his usual good-natured smile. "A bit of masonry has fallen from the tower. See, the floor is covered with similar pieces."
"If anyone should be up there——" suggested von Ruhle, pointing to the top of the tower.
The lads could feel their hearts thumping against their ribs. Through a small crack in the planking they could see the eyes of the two Germans directed upwards.
"Impossible; there are no steps," declared Ramblethorne. "Besides, what object would anyone have in ascending a tower on a day like this? I fully appreciate the danger of being overheard, of course. We've said enough to find ourselves faced by a firing-party in the Tower of London, my friend."
"Don't!" expostulated von Ruhle, closing his eyes as if to shut out the unpleasant mental vision. Then: "You have the signalling apparatus, I hope?"
"Trust me for that, von Ruhle," replied his companion, tapping his breast-pocket. "All we have to do is to wait until yonder lighthouse exposes its light. Really the ways of these English pass understanding. They rigorously forbid the showing of lights in private houses on shore, imagining that our agents would be so foolish as to start blinking with a lamp; yet they allow these lighthouses to work as usual, and obligingly enable us to communicate to our hearts' content."