Though expression of assent and not actual assent creates a contract, a writing purporting to be a contract and not ambiguous in its language may be wholly void. If without negligence on his part, a signer attached his signature to a paper assuming it to be a paper of a different character, the paper is void. Such a mistake without negligence will not often occur in the absence of some such fraud, as substituting by sleight-of-hand, for a paper which has been agreed upon, a different one. Nevertheless the situation is possible without actual fraud, and if it occurs whether induced by fraud,26 or without it, no contract is formed.27

25 See Preston p. Luck, 27 Ch. D. 497; Silva p. Silva, 32 Col. App. 115, 162 Pac. 142, and infra, Sec.Sec. 606, 607, 610. In Joilet Bottling Co. v. Joliet Brewing Co., 254 111. 215, 98 N. E. 283, the court said:

"Where ft contract, is ambiguous and has been interpreted by the parties to it, courts will regard the interpretation placed upon the contract by the parties themselves. This rule can have no application to a construction of the contract before us in this case, because it is not ambiguous; and the intention of the parties to it is not to be deter' mined by evidence, but by the language employed in the contract itself." See infra, Sec.Sec.606, 607.

26See infra, Sec.1488.

27See Thoroughgood's Case, 2 Coke, 9a (considered in L. R. 4 C. P. 711); Davis v. Snider, 70 Ala. 315; Bank v. Webb, 108 Ala. 132,19 So. 14; Yoch v. Insuranoe Co., 111 Cal. 503, 44 Pac.

189, 34 L. R. A. 857; Meyer p. Haas, 126 Cal. 560, 58 Pac. 1042; Green v. Maloney, 7 Houst. 22; Brooke v. Matthews, 78 Ga. 739, 3 S. E. 627; Rock-ford, etc., R. R. Co. p. Shunick, 65 111. 223; Eldorado Jewelry Co. p. Darnell, 135 Ia. 555, 113 N. W. 344, 124 Am. St. Rep. 309; O'Donnell v. Clinton, 145 Mass. 461, 14 N. E. 747; Adolph v. Minneapolis &. Pac. Ry. Co., 58 Minn. 178, 59 N. W. 959; Wright v. McPike, 70 Mo. 175; Alexander v. Brogley, 62 N. J. L. 584, 41 Atl. 691, 63 N. J. L. 307, 43 Atl. 888; Jackson v. Hayner, 12 Johns. 469; Green p. North Buffalo Township, 56 Pa. St, 110; Schuylkill County v. Copley, 67 Pa. St. 386, 5 Am. Rep. 441; Wanner v. Landis, 137 Pa. St. 61, 20 Atl. 950; Coates v. Early, 46 S. C. 220, 24 S. E. 305; Cameron v. Estabrooks, 73 Vt. 73, 50 Atl. 638; Gross v. Drager, 66 Wis. 150,28 N. W. 141; Warder Co. p. Whitish, 77 Wis. 430, 46 N. W. 640;

It is as if the offeror in his sleep said words expressive of an offer, which were accepted. Though neither will to create a legal obligation, nor accurate understanding of the meaning of an offer and acceptance is essential to the creation of a contract, intent to do the act which amounts to an offer or acceptance or at least negligently allowing the appearance of such an intent is essential.