Interesting quote there from 'Jordan am a hard road':

Oh, Croppies ye'd better be quiet and still
Ye shan't have your liberty, do what ye will
As long as salt water is formed in the deep
A foot on the necks of the Croppy we'll keep.

Is the line about salt water part of an old expression for a very long time / eternity?
It's just that it echoes the sentiment in 'Bugeilio's gwenyth gwyn'
Tra bo dwr y mor yn hallt (while sea-water remains salty)

Cheers
Nigel