This is an interesting series but I haven't been paying much attention to it. Until now when these latest two episodes were bought to my attention.
Last week we had a North America buckskin map. Transcript is here.
But this week is better, Darwin's chronometer (or, rather, one of the 22 chronometers on HMS BEAGLE). Full transcript is here. I read Longitude with much interest some years ago so this was a good 15 mins of radio listening.
A bit more snooping around has unearthed a Hebrew Astrolabe and a Mexican codex map. It's funny but I didn't find the British Museum at all inspiring when I was there last month - it just goes to show that the story behind the object can make all the difference.