But now there came a strange interruption.

The tall chimney which over-topped the remainder of the ruins rose right above their hiding-place.

There came a whistle in the air, and then a sounding smack, and the fragments of a broken arrow fell about their ears.

Some one from the upper quarters of the wood, perhaps the very sentinel they saw posted in the fir, had shot an arrow at the chimney-top.
Matcham could not restrain a little cry, which he instantly stifled, and even Dick started with surprise, and dropped the windac from his fingers.
But to the fellows on the lawn, this shaft was an expected signal.

They were all afoot together, tightening their belts, testing their bow-strings, loosening sword and dagger in the sheath.