> In 1854, it was forecast by Scottish mathematician Lord Kelvin that there were only 300,000 years left. I'm not really sure what the convention is with lords

> In 1854, it was forecast by Scottish mathematician Lord Kelvin that there were only 300,000 years left. I'm not really sure what the convention is with lords, but William Thomson, born in Belfast to Irish parents, did not become 1st Baron Kelvin and Lord Kelvin until 1892. So he was either or both Irish and Northern Irish, and also British. But when (and how) did William Thomson become Scottish?