“Stop！” said Polly. “Aren’t we going to mark this pool？”
They stared at each other and turned quite white as they realized the dreadful thing that Digory had just been going to do. For there were any number of pools in the wood， and the pools were all alike and the trees were all alike， so that if they had once left behind the pool that led to our ownworld without making some sort of landmark， the chances would have been a hundred to one against their ever finding it again.
Digory‘s hand was shaking as he opened his penknife and cut out a long strip of turf on the bank of the pool. The soil （which smelled nice） was of a rich reddish brown and showed up well against the green. “It’s a good thing one of us has some sense，” said Polly.
“Well， don‘t keep on gassing about it，” said Digory. “Come along， I want to see what’s in one of the other pools.” And Polly gave him a pretty sharp answer and he said something even nastier in reply. The quarrel lasted for several minutes but it would be dull to write it all down. Let us skip on to the moment at which they stood with beating hearts and rather scared faces on the edge of the unknown pool with their yellow rings on and held hands and once more said “One.Two.Three.Go！”