A showing of the substance and the relevance of the excluded evidence must be made to perfect the record for appellate review. The right to make an offer of proof is virtually absolute.
Maine law is instructive. M.R.Evid. 103(a)(2) provides that unless the expected proof was apparent from the context error can be predicated on a ruling excluding evidence only if the proponent made known to the court the substance of the proffer. Id.; e.g., Banville v. Huckins, Me., 407 A.2d 294, 298 (1979). This rule not only enables the trial court to reconsider its ruling but also ensures a basis for the Court to determine on appeal whether the ruling was erroneous. E.g., State v. Rich, Me., 395 A.2d 1123, 1130 (1978), cert. denied, 444 U.S. 854, 100 S. Ct. 110, 62 L. Ed. 2d 71 (1980); R. Field & P. Murray, Maine Evidence § 103.4 (1976).