'Well, we can report back to Ms Rubenach that we've found the source,' says Penny Marx.

'One of the sources,' says Hilary.

'Today...' says Dudley. 'If the snow wasn't down this far then it would be melting somewhere else.'

'And in summer time,' says Hilary, 'does it come out of a hole in the ground or something, like a spring?'

'It's called the Springs further down the hill, isn't it?' says Penny Marx.

'I'm confugued,' says Farrel, who has watched this interchange intensely.