A few years ago I remembered how much I enjoyed skipping as a child, and used to spend hours at it (often alone, as I have no siblings) and thought I might take it up again as a form of cardiovascular exercise. I was fitter then than I am now, and I managed about 5 minutes before I started to feel bored, and after about 15 couldn't take the tedium any longer (now, I think I'd probably be exhausted as well!) I never tried it again. My attention span has clearly diminished (something I have long suspected.)

The Kenneth Grahame error looks like one that wasn't picked up because of an initial transcription error which multiple editors might miss--not like a misspelling or something which makes nonsense out of the quotation--the implication is still roughly the same: though 'clean' is a much more telling word than 'clear' in the context. The Lewis error is hideous, though! Poor mangled prose!