John McLean, Duncan's Heirs v. United States…
“ It is a principle of the common law, too well settled to be controverted, that where an instrument is delivered as an escrow, or where one surety has signed it, on condition that it shall be signed by another, before its delivery, no obligation is incurred, until the condition shall happen. And if it appeared in the present case, that Abner L. Duncan signed the bond, to be delivered on condition that Thomas Duncan should execute it, there can be no doubt, the plea should have been sustained in the court below. ”
