"But what's it doing up here, Tom? It looks as if it might be a pump-house. Look! There's a chimney. And what's that sort of chute leading over the edge that side? I say, Tom! I've got it. I know what it is! Remember I told you just now that the place where we found Mackie looked as if it had once been the entrance to one of the old mines and about the cable railway?... Well, I bet this is the engine-house and that the wires of the cable finish here. I was wondering where they went."

They hurried on and soon found Peter to be right. The derelict building was perched on the side of the ridge - rather like a medieval castle on the top of a rock - with a squat, square tower facing the Dingle. From one opening in the tower stretched the wires of the cable railway and, on the other side, a wide, iron trough bridged the track on which they were standing. Tom ran across and looked over the edge.

"See here, Peter! There's a wooden chute running down the side of the mountain. Come and look! I've seen one of these before over Ludlow way. They used it to slide tree trunks down into the valley."

Peter joined him and was surprised to see how steep was this side of the ridge.

"This is thrilling, Tom. We must all come here and explore. We could spend a whole day here... I think I see what happened. They mined the ore the other side of the Dingle where we were this morning and then it was hauled across the valley on the cable. Then, I expect, the trucks were emptied into that chute thing up there and the ore went tumbling down into that valley where there's a road or a railway. Let's see if we can get inside."

The engine-house looked as if it had been neglected for years. The trees and undergrowth and nettles grew close to the walls and a dilapidated door hung dejectedly on one hinge. Tom pushed it gently and it uttered a plaintive squeak and moved under his hand. They stepped over the threshold and paused until their eyes became accustomed to the gloom. Then they saw an iron-floored gallery above them - rather like the iron floor of a pier - and the bulk of a mighty drum and some machinery. On their left, in the shadows, a dark cylinder towered up into the roof.

"Bet that's a steam-engine," Tom said. "But I wonder where they got the water? Reckon they'd have to pump from down below somewhere... There's a ladder here, Peter. Let's explore up top."