They crept over the ground, and took post under a tall, thick-leaved beech nearly a hundred yards away.
"I don't see any chance of getting in," said Warrender, "and that's a pity. I wanted to see them actually turning out their forged notes."
"I suppose it was Gradoff going out again we heard just now," said Armstrong. "If he and Rod are both away, there can't be more than four others in the tower, probably not so many. They'll take turns at night-work."
"That doesn't matter. Any forcible entry is quite out of the question, if that's what you're thinking of. I say, isn't that a light up the tower?"
More than half-way up the wall a faint streak of light was visible.
"Evidently there's some one in the top room," said Warrender. "Some one sleeps there, I suppose. The machine is on the ground floor. Where light gets out, we should be able to see in. You've done some climbing already to-night; are you game to clamber up the ivy? There's no other way."
"I weigh eleven stone," said Armstrong, dubiously.
"But ivy's pretty tough. It may support you. You may find foothold in the wall."
"Hanged if I don't try. You'll stand underneath and break my fall if I tumble. I reckon it's about thirty feet up; plenty high enough to break one's neck or leg."
They hastened to the foot of the tower. With Warrender's help, Armstrong got a footing in the lower embrasure. Then, taking firm hold of the stout main stem of the ivy, he began to swarm up, seeking support for his feet in the thick, spreading tendrils and in notches of the stone-work. Warrender watched him hopefully. Slowly, inch by inch, he ascended. He gained the second embrasure, rested there a few moments, then climbed again, and was almost half-way to his goal, when he felt the ivy above him yield slightly. Digging his feet into the wall, he hung on, but at the first attempt to ascend he felt that the attenuated stem would no longer support his weight, and began slowly to lower himself.