From old "Treasure Island". Captain in grog-shop, just got cup of rum and says:
"Oh, I see what you’re at — there"; and he threw down three or four gold pieces on the threshold.
1) What does "I see what you’re at — there" means?
2) What does "threshold" also means? Feels like top of bar counter.
When I looked up the meaning of threshold, I found this: "A strip of wood or stone forming the bottom of a doorway and crossed in entering a house or room,” which doesn't seem to fit in context.