Right of appropriation: debtor may earmark payments; absent that, creditor may appropriate payments, with interest prioritized. The right of appropriation allows a debtor to designate which of several debts a payment will discharge, and if the creditor accepts that payment he must apply it accordingly; if the debtor makes no appropriation the right passes to the creditor who may appropriate up to the last moment or until it would be inequitable, and where neither appropriates payments will be applied first to interest due before being applied to principal unless a contrary intention exists.