157. Fact of agency not disclosed.

Where a person makes a contract in his own name without disclosing either the name or the existence of a principal, he is personally liable on the contract to the other contracting party, though he may be in fact acting on a principal's behalf1. He will continue to be liable even after the discovery of the agency by the other party, unless and until there has been an unequivocal election by the other contracting party to look to the principal alone