the contents of a document is allowed to be given, but these are a part of the general law of evidence, and the rules which govern the admissibility of such evidence are to be found in treatises on the subject. § 2. Evidence as to fact of agreement. Thus far we have dealt with the mode of bringing a document, purporting to be an agreement, or part of an agreement, before the court. But extrinsic evidence is admissible to show that the document is not in fact a valid agreement. It may be shown by such evidence that the contract was invalid for want of consideration, of capacity of one of the *parties, of genuineness of consent, of legality [*260] of object. Extrinsic evidence is used here, not to alter the purport of the agreement, but to show that there never was such an agreement as the law would enforce. It may also be shown by extrinsic evidence that a parol condition suspended the operation of the contract. Thus a deed may be shown to have been delivered subject to the happening of an event or the doing of an act. Until the event happens or the act is done the deed remains an escrow, and the terms upon which it was delivered may be proved by oral or documentary evidence extrinsic to the sealed instrument. In like manner the parties to a written contract may agree that, until the happening of a condition which is not put in writing, the contract is to remain inoperative. Campbell agreed to purchase of the Messrs. Pym a part of the proceeds of an invention which they had made. They drew up and signed a memorandum of this agreement on the express verbal understanding that it should. not bind them until the approval of one Abernethie had been expressed. Abernethie did not approve of the invention, and Campbell claimed that there was no contract. Pym contended that the agreement was binding and that the verbal condition was an attempt to vary by parol the terms of a written contract. But the court held that evidence of the condition was admissible, not to vary a written contract but to show that there had never been a contract at all.1 The law was thus stated by Erle, J.: The point made is, that this is a written agreement, absolute on the face of it, and that evidence was admitted to show it was conditional and if that had been so it would have been wrong. But I am of opinion that the evidence showed that in fact there was never an agreement at all. The production of a paper purporting to be an agreement by a party, with his signature attached, affords a strong presumption that it is his written agreement; and if in fact he did sign the paper animo contrahendi, the terms contained in it are conclusive, and cannot be varied by parol *evidence: but in the [*261] present case the defence begins one step earlier the parties met and expressly stated to each other that, though for convenience they would then sign the memorandum of the terms, yet they were not to sign it as an agreement until Abernethie was consulted. I grant the risk that such a defence may be set up without ground; and I agree that a jury should therefore always look on such a defence with suspicion; but, if it be proved that in fact the paper was signed with the express intention that it should not be an agreement, the other party cannot fix it as an agreement upon those so signing. The distinction in point of law is, that evidence to vary the terms of an agreement in writing is not admissible, but evidence to show that there is not an agreement at all is admissible.' Pym v. 6 E. & B.374. (3) Evi dence as General rule. § 3. Evidence as to the terms of the contract. When we come to extrinsic evidence as affecting the to terms. terms of a contract, the admissibility of such evidence is narrowed to a small compass; for according to the general law of England the written record of a contract must not be varied, or added to by verbal evidence of what was the intention of the parties.' 1 Reynolds v. Robinson, 110 N. Y. 654, H. & W. 502; Westman v. Krumweide, 30 Minn. 313; Blewitt v. Boorum, 142 N. Y. 357. Blackburn, J., Burges v. 3 B. & S. 696. Exceptions. (a) Supplement ary terms. Jervis v. 8 Ch. 351. Collateral terms. We find exceptions to this rule (a) in cases where terms are proved supplementary, or collateral to so much of the agreement as is in writing; (b) in cases where explanation of the terms of the contract is required; (e) in the introduction of usages into the contract; (d) in the application of special equitable remedies in the case of mistake. (a) It may happen that the parties to a contract have. not put all its terms into writing. Evidence of the supplementary terms is then admissible, not to vary but to complete the written contract. Jervis agreed to assign to Berridge a contract for the purchase of lands from M. The assignment was to be made upon certain terms, and a memorandum of the bargain was made in writing, from which at the request of Berridge some of the *terms were omitted. In [*262] fact the memorandum was only made in order to obtain a conveyance of lands from M. When this was done and Berridge had been put in possession he refused to fulfil the omitted terms which were in favour of Jervis. On action being brought he resisted proof of them, contending that the memorandum could not be added to by parol evidence. Lord Selborne however held that the memorandum was a mere piece of machinery obtained by the defendant as subsidiary to and for the purposes of the verbal and only real agreement under circumstances which would make the use of it, for any purpose inconsistent with that agreement, dishonest and fraudulent.'1 Again, evidence may be given of a verbal agreement collateral to the contract proved, subjecting it to a term unexpressed in its contents. Such a term however can 1 Wood v. Moriarty, 15 R. I. 518, H. & W. 430; 78 N. Y. 74; Wood Mowing &c. Co. v. Gaertner, 55 shaw v. Combs, 102 Ill. 428. Chapin v. Dobson, only be enforced if it be not contrary to the tenor of the written agreement. Thus, where a farmer executed a lease upon the promise of the lessor that the game upon the land should be killed down, it was held that he was entitled to compensation for damage done to his crops by a breach of such a verbal promise, though no reference to it appeared in the terms of the lease.1 Mellish, L.J., in giving judgment said: 'No doubt, as a rule of law, if parties enter into negotiations affecting the terms of a bargain, and afterwards reduce it into writing, verbal evidence will not be admitted to introduce additional terms into the agreement; but, nevertheless, what is called a collateral agreement, where the parties have entered into an agreement for a lease or for any other deed under seal, may be made in consideration of one of the parties executing that deed, unless, of course, the stipulation contradicts the terms of the deed itself. I quite agree Erskine v. that an agreement of that kind is to be rather closely watched, and that we should not admit it without seeing clearly that it is substantially proved.' Adeane, 8 Ch. at p. 766. (b) Explanation of terms; to identify parties, Wake v. N. Harrop, 769. or subject (b) Evidence in explanation of terms may be evidence of the identity of the parties to the contract, as where two persons have the same name, or where an agent contracts in his own *name but on behalf of a principal whose [*263] name or whose existence he does not disclose.2 Or it may be a description of the subject-matter of the matter, contract, as in a case in which A agreed to buy of X certain wool which was described as 'your wool,' and the right of X to bring evidence as to the quality and quantity of the wool was disputed. The court held that it was admissible.3 Or such evidence may be an explanation of some word not describing the subject-matter of the contract but the 1 Thurston v. Arnold, 43 Iowa, 43 H. & W. 515; Van Brunt v. Day, 81 N. Y. 251; Naumberg v. Young, 44 N. J. L. 331; Green v. Batson, 71 Wis. 54. 2 Andrews v. Dyer, 81 Me. 104; Byington v. Simpson, 134 Mass. 169. 3 Bulkley v. Devine, 127 Ill. 406; Clark v. Coffin Co., 125 Ind. 277. Y Macdonald v. Longbot tom, 1 E. & E. 977. to show application of phrases. 3 B. & S. 669. 6 nature of the responsibility which one of the parties assumes in respect of the conditions of the contract. Where a vessel is warranted seaworthy,' a house promised to be kept in tenantable' repair, a thing undertaken to be done in a reasonable' manner, evidence is admissible to show the application of these phrases to the subject-matter of the contract, so as to ascertain the intention of the parties.1 In Burges v. Wickham, a vessel called the Ganges, intended for river navigation upon the Indus, was sent upon the ocean voyage to India, having first been temporarily strengthened so as to be fit to meet the perils of such a voyage. Her owner insured her, and in every policy of marine insurance there is an implied warranty by the insured that the vessel is 'seaworthy.' The Ganges was not seaworthy in the sense in which that term would. be ordinarily applied to an ocean-going vessel, but her condition was made known to the underwriters, and though the adventure was more dangerous than an ordinary voyage to India, there was a reasonable probability that it would be brought to a safe ending. At any rate, the underwriters took the risk at a higher premium than usual, and in full knowledge of the facts. The Ganges was lost, and the owner sued the underwriters; they defended the action on the ground that the vessel was unseaworthy in the sense in which the word was applied to an ocean voyage, and they resisted the admission of evidence to show that, with reference to this particular vessel and voyage, the term was understood in a modified sense. The evidence was held to be admissible on grounds which are stated with the utmost clearness by Blackburn, J.: [*264] 1 Ganson v. Madigan, 15 Wis. 144, H. & W. 504; Manchester Paper Co. v. Moore, 104 N. Y. 680. If the parties have used the term in different senses, the contract is voidable for mistake. Hazard v. New England Marine Ins. Co., 1 Sumner (U. S. C. C.), 218. |