Ken obeyed instantly.  He knew nothing of mountaineering himself, but realised that Roy did.  Without a moment’s hesitation Roy turned round with his back to the ravine, and catching Ken’s hands, let himself drop quietly till his long body dangled at full length against the face of the cliff.

[Illustration:  ‘The strain on Ken’s arms was awful.’]

The strain on Ken’s arms was awful.  The depths below made his head swim.  But he set his teeth, dug his toes into the earth, and held on like grim death.

‘Let go,’ said Roy briefly.

To Ken it seemed as though he were dropping his friend into the awful abyss.  But he obeyed without hesitation.

There was a second of ghastly suspense.  Then Roy was standing on the almost invisible ledge, balancing himself, spreadeagled against the face of the rock.

His hands moved slowly, the fingers groping for a hold.  He found it, and clutching tightly with his left, raised his right hand.

‘My bayonet,’ he said quickly.

Ken slipped it out of its socket and gave it him.

Roy took it and carefully and deliberately drove it into a crevice in the rock on a level with his head.

‘Chuck the rifles over,’ he said.  ‘You mustn’t leave them.’

Ken obeyed.  A hollow crash came up from the black depths.

‘Now I’m ready for you,’ said Roy.  His voice was so cool and steady that it gave Ken some confidence.  ’Get as good a grip as you can and let go when I tell you.’

For a moment it seemed to Ken that he could not do what was asked.  In any matter of fighting he was Roy’s equal—­indeed his superior, for he was better able to keep his head in the thick of it.

But he had had no experience of heights, and the blood ran cold in his veins at the idea of dropping over this terrific precipice.  It seemed to him the only possible result must be that he would knock Roy off his narrow perch, and that they would go crashing together into the yawning depths of the abyss.

‘You’re not scared, are you?’

The contempt in Roy’s tones stung Ken to the quick.  He hesitated no longer.  Turning quickly, he clutched the rocky ledge and recklessly swung himself down.

‘Good man!  I knew you could do it.  Steady now!  I’ve got you.  Let go!’

Once more Ken obeyed.  He fully believed that he was going to his doom.  Instead, to his intense surprise, he found himself balancing on the ledge beside Roy.

Roy gave a low laugh.

’Sorry I insulted you, old man.  I just had to.  I know the sort of funk that takes you the first time you try this kind of game.  And I give you my word there are precious few chaps would have stuck it at all.’

‘Now I’ll tell you something to console you,’ he continued.  ’The ledge widens to my right, and runs in under a big overhang.  Once we’re under that, we’re as safe as rats in a granary.  No one can see us from up above or from anywhere else, so far as that goes.’