Consent is manifested by the meeting of the offer and the acceptance upon the thing and the cause which are to constitute the contract. The offer must be certain and the acceptance absolute. A qualified acceptance constitutes a counter-offer.
Acceptance made by letter or telegram does not bind the offerer except from the time it came to his knowledge. The contract, in such a case, is presumed to have been entered into in the place where the offer was made. (1262a)