It seemed a long time before it came opposite. Then at last Ken gave one word.
'Now!'
In an instant they were both on their feet, Roy tugging on the lever, Ken bracing all his weight on the big rock.
It moved, it rolled slowly over, seemed to pause a moment on the edge of the bank, then suddenly shot forward. Ten feet below, it alighted on the slope, rebounded, and at the same time started half a dozen other stones. In a moment a rock avalanche was roaring down the steep. The great stone led the way. In a series of gigantic leaps, each longer than the last, it thundered downwards, at each jump starting fresh tons of the loose shale which covered the bank.
A cloud of dust rose like smoke, and hid all below. Then from out the cloud came squeals and shrieks.
In their excitement, Ken and Roy actually forgot to send fresh stones to follow the first. There was no need. When the dust cloud cleared, one mule which had broken loose was galloping madly across country, the rest were down and dead.
The gun, dismounted, was half buried in a pile of shale which lay feet deep across the road. Of the men, not one remained. Most were not only dead, but buried. Two only lay clear, and to all appearance they were as dead as their companions.
Roy looked at Ken.
'What you might call a clean bit of work,' he said, but though he tried to smile, there was something like awe in his voice.
'Yes. A ten-inch shell could hardly have done more,' Ken answered. 'Poor beggars! It's rather ghastly wiping 'em out like that, but one has got to remember that that gun would have probably finished ten times the number of our chaps if they'd got it into position.