The first message sent through the transatlantic cable stretching from Valentia Island, Ireland to White Sand Bay, Newfoundland was in 1866. The message was sent by Latimer Clark. After a few unsuccessful attempts he came up with the idea of making a small electric cell from a touch of sulphuric acid, a little bit of zinc and a smidgen of silver.
The silver came from a thimble like the one above. It was lent to him by Emily Fitzgerald, the daughter of the Knight of Kerry. Emily's thimble generated enough current to send the signal 3,700 miles across the Atlantic in a mere second. Imagine that - high speed communication - from a thimble! The thimble now resides in the London Science Museum.
This particular design of thimble is now known as the Atlantic Cable thimble. I think this one is from around 1870 judging by its tallness and slightly domed top. It's been used, is a bit dinted in places and is slightly out of the round. That's a strange turn of phrase I know. It basically means its more of an oval shape than circular. Silver is an incredibly soft metal so thimbles are easily damaged through use.
I really must look into visiting the museum in London to see if Emily's thimble shows any signs of use or even any signs of its brush with fame.