CORRESPONDENCE. The letters written by one to another, and the answers thereto, make wbat is called the correspondence of the partie's.
3. When an offer to contract is made by letter, it must be accepted unconditionally for if the precise terms are changed, even in the slightest degree, there is no contract. 1 Bouv. Inst. n. 904. See, as to the power of revoking an offer made by letter, 1 Bouv. Inst. n. 933.