I was amazed to see an article about lighthouse lamps on TV a while ago.
They showed a massive bath of mercury that the entire lamp system of a
lighthouse floated on.
It was used as a very low friction bearing system.
Apparently it was quite common - simple & reliable.
Lighthouse keepers used to have to strain the mercury through a cloth
when it got too much surface contamination.
It probably wasn't just the isolation that caused lighthouse keepers to
go mad or suicide.
Regards,
Brian.
