Q From Philip Madell: What does Huckleberry Finn mean when he says that Mary Jane ‘had more sand in her than any girl I ever see’? I see it means courage, resolve, but how did it get to mean that?
A Sand here has just the same sense as the older grit, clear grit, or true grit, that refer to a person who has strength of character, pluck, stamina, the ability to see things through to the end. The reference here, presumably is to the toughness of grit, especially that in gritstone, a common name for the material that made up the stones of a corn mill.
Why sand should suddenly pop up in its place — sometime near the end of the 1860s — is hard to say, though it is an obvious enough synonym. In its earliest appearances, it forms part of expressions such as sand in his gizzard or sand in his craw, which are obvious enough references to the small stones that some birds swallow into their gizzards to help grind their food. (The second of these expressions is still sometimes used by older people in the US, though it is unknown to most young ones, I am told.)
Mark Twain uses both grit and sand in successive sentences in that place in Huckleberry Finn: “She had the grit to pray for Judus if she took the notion — there warn’t no backdown to her, I judge. You may say what you want to, but in my opinion she had more sand in her than any girl I ever see; in my opinion she was just full of sand”.
How these became interchangeable terms is a small mystery that needs to be resolved, but don’t bank on anyone finding the solution anytime soon!