I was curious about this line in one of the letters cited:

>Gutapercha ring making is all the go now by the men and some of them are making really beautiful ones.

So wikipediaed gutapercha, which turns out to be a tree. The same name is used for a latex made from the tree. This material made undersea cables possible in the early days.

But I was curious: why rings? Well, it might have something to do with the caning of Charles Sumner in 1856. Brooks, a pro-slavery U.S. representative beat Sumner, an abolitionist representative, nearly to death on the Senate floor with a gutapercha cane. Brooks' colleagues then wore necklaces with rings made from the shattered cane. So that letter might've come from a Confederate soldier.