The writing, upon which this action is brought, contains a promise on the part of the defendant only. It recites, imperfectly and in general terms, the agreement to be performed on the part of the plaintiff, as the consideration upon which the promise of the defendant is made. At the trial, the defendant offered evidence to show the whole arrangement between the parties; particularly the representations of the plaintiff as to the material of which the chart was to be made, and the manner in which it would be published; and contended that he was not bound to pay, because the plaintiff had failed so to make and publish the chart. The court excluded the evidence, and ruled that no evidence of extrinsic facts was admissible for any purpose.
The alleged representations related to that which was then in the future, and were, in one aspect, of a promissory nature. The principle of law is clear and well settled, that the obligation of a written contract cannot be abridged or modified by or made conditional upon another preceding or contemporaneous paroi agreement, not referred to in the writing itself. Trustees of Church in Sanson v. Stetson, 5 Pick. 506. Wakefield v. Stedman, 12 Pick. 562. St. Louis Insurance Co. v. Homer, 9 Met. 39. Adams v. Wilson, 12 Met. 138. Underwood v. Simonds, Ib. *66275. Hanchet v. Birge, lb. 545. Prescott Bank v. Caverly, 7 Gray, 217. Small v. Quincy, 4 Greenl. 497. But it is equally well settled that, for the purpose of applying the terms of the written contract to the subject matter, and removing or explaining any uncertainty or ambiguity which arises from such application, paroi testimony is admissible, and has a legitimate office. For this purpose, all the facts and circumstances of the transaction out of which the contract arose, including the situation and relations of the parties, may be shown. Gerrish v. Towne, 3 Gray, 82. Herring v. Boston Iron Co. 1 Gray, 134. Sutton v. Bowker, 5 Gray, 416. Bradley v. Washington, Alexandria & Georgetown Steam Packet Co. 13 Pet. 89. Price v. Mouat, 11 C. B. (N. S.) 508. The subject matter of the contract may be identified by proof of what was before the parties, by sample or otherwise, at the time of the negotiation. Bradford v. Manly, 13 Mass. 139. Hogins v. Plympton, 11 Pick. 97. Clark v. Houghton, 12 Gray, 38. Haven v. Brown, 7 Greenl. 421. The terms of the negotiation itself, and statements therein made, may be resorted to for this purpose. Foster v. Woods, 16 Mass. 116. Sargent v. Adams, 3 Gray, 72. Mumford v. Gething, 7 C. B. (N. S.) 305. Chadwick v. Burnley, 12 Weekly Rep. (Q. B.) 1077. The meaning of ambiguous terms in the contract may be fixed by showing that a particular significance had become attached to those terms by reputation, usage of trade, or otherwise. Woods v. Sawin, 4 Gray, 322. Hart v. Hammett, 18 Verm. 127. Putnam v. Bond, ante, 58. The purpose of all such evidence is, to ascertain in what sense the parties themselves used the ambiguous terms in the writing which sets forth their contract. If the previous negotiations make it manifest in what sense they understood and used those terms, they furnish the best definition to be applied in the interpretation of the contract itself. The effect must be limited to definition of the terms used, and identification of the subject matter. If so limited, it makes no difference that the language of the negotiations relates to the future, and consists in positive engagements on the part of the other party to the contract. Their effect depends, not upon their promissory obligation, but upon the aid *67they afford in the interpretation of the contract in suit. They are not the less effective for the purposes of explanation and definition because they purport to carry the force of obligation.
The contract in suit may illustrate this principle in a point that is not in dispute. The defendant agrees to pay fifty dollars “ for inserting business card,” &c. In applying this stipulation, if the defendant had a business card distinctively known and recognized as such, there would be no difficulty in giving effect to the contract. But the identification of that card would involve the whole principle of admitting paroi testimony for the interpretation and application of written contracts to the subject matter. It could be done only by the aid of paroi testimony. Suppose he had several business cards, differing in form" and contents, but one was selected and agreed upon for the purpose at the time the contract was signed; or that one had been prepared specially for the purpose. Clearly, paroi testimony would be competent to identify the card so selected or prepared ; and to prove that the parties assented to and adopted it as the card to which the contract would apply. Suppose, thirdly, that no such card had been selected or prepared, but its form, contents and style had been described verbally and assented to, and the plaintiff had agreed to insert it as so described. Such evidence may be resorted to, not for the promise it contains, but for the aid it affords in fixing the meaning and applying the general language of the written contract.
The same considerations render the evidence offered by the defendant competent for similar purposes. The term “ his advertising chart ” requires to be practically applied. The representations of the plaintiff are in the nature of a description of the vehicle by which the publication of the business card was to be effected ; and his account of the disposition he proposed to make of the charts was a description of the extent and the sense in which it was to be an “ advertising chart.’’ The representations as to the material of which the chart was to be made, and the mode of publication, constitute his description of what “ his advertising chart ” was. Macdonald v. Longbottom, 1 El. & El. 977.
*68When applied to such an article as this, the word “ published ’• can have no fixed signification which the court can apply to the contract. What was a sufficient publication within the sense and intent of the contract must be ascertained and determined by the jury, in the light of all the facts of the case. We think the jury may consider the plaintiff’s own description of the chart, and his representations as to the mode of publishing it, upon this question. Atwood v. Cobb, 16 Pick. 227. Ellis v. Thompson, 3 M. & W. 445.
It follows, that the evidence offered by the defendant was improperly excluded. It was competent for the purposes herein-before indicated. It is unnecessary to consider the questions which have been discussed with so great thoroughness and ingenuity of argument by the plaintiff’s counsel, upon the defence of fraud and misrepresentation; because in the view of the case which we have taken the whole force of the defendant’s testimony will bear upon the interpretation of the contract itself.
Exceptions sustained.