“Come on，” said Digory. “Which pool shall we try？” “Look here，” said Polly， “I’m not going to try any newpool till we‘ve made sure that we can get back by the old one. We’re not even sure if it‘ll work yet.”
“Yes，” said Digory. “And get caught by Uncle Andrew and have our rings taken away before we’ve had any fun. No thanks.”
“Couldn‘t we just go part of the way down into our own pool？” said Polly. “Just to see if it works. Then if it does， we’ll change rings and come up again before we‘re really back in Mr Ketterley’s study.”
“Can we go part of the way down？”
“Well， it took time coming up. I suppose it‘ll take a little time going back.”
Digory made rather a fuss about agreeing to this， but he had to in the end because Polly absolutely refused to do any exploring in new worlds until she had made sure about getting back to the old one. She was quite as brave as heabout some dangers （wasps， for instance） but she was not so interested in finding out things nobody had ever heard of before； for Digory was the sort of person who wants to know everything， and when he grew up he became the famous Professor Kirke who comes into other books.