The rule that prior or contemporaneous negotiations can not be used to contradict, add to, or otherwise vary, a written contract applies not merely to the letter of the written contract, but also to its legal effect.1 Thus where no time is fixed for performance, and the implication therefrom would,be that a reasonable time was allowed, evidence that a specific time had been agreed upon is inadmissible.2 It has been held, however, that among other circumstances evidence of conversations between the parties to the contract may be considered to show what they considered to be a reasonable time.3 If the contract in legal effect calls for prompt performance, an oral contract delaying performance until some specified time in the future is unenforceable. Thus where a bill of exchange has been drawn an oral contract that it should not be presented for payment until another draft had been paid was unenforceable.4 It has been held, however, that an oral contract, made when a check was delivered that it should not be presented until a certain date in the future was valid.5 So under a contract of sale, with delivery in installments at a gross price, the legal effect of which was to make the price payable when the entire quantity was delivered, an oral contract that at the delivery of each installment the price therefor should be paid was unenforceable.6 So a guaranty for a specified amount to be advanced by the maker, payable on demand after thirty clays, can not be modified by showing that the guaranty was to last for thirty days only.7 If the written contract is so drawn that time is not of its essence, the parties cannot show a contemporaneous oral agreement that time should be of the essence.8 So under a contract appointing an agent "in the immediate vicinity of" a certain town, extrinsic evidence is inadmissible to show that he was to have the exclusive agency.9 Where a check was given, payable on the date thereof, the drawer could not show an oral agreement that the check was not to bear interest.10 So where two persons have signed a contract in such a way that they are jointly liable thereon, an oral agreement that each shall be severally liable for one-half of the liability cannot be used to modify the contract.11 So where A, a member of a firm, made and signed a written entry of part payment on a partnership note barred by the statute of limitations the legal effect of which was to make A liable for the entire amount of the note, A cannot show that he signed under an oral contract that he should be liable for only one half the amount of the note.12 So in a contract by one person to support another, where no place of support is fixed, and therefore the party to be supported may fix any reasonable place for receiving support, extrinsic evidence is inadmissible to show that the parties had agreed that such a support was to be furnished at a fixed place.13 It has, however, been held under a contract of employment that where no specific place of performance is fixed, oral evidence of the intention of the parties direct is admissible to show on what locality they had agreed.14 So where no rate is fixed in a bill of lading, and accordingly a reasonable rate is implied, an oral agreement between the parties fixing the rate cannot be enforced.15 A written contract of hire cannot be contradicted by showing that the employer could terminate the contract at will.16 A contract to convey land "for all legitimate railroad purposes " cannot be modified by showing an oral agreement not to erect an eating house or hotel thereon;17 nor can a lease for "business purposes" be modified by a contemporaneous oral agreement not to use the premises as a saloon.18 A contract for the sale of land which states the area as an estimate, and provides for a survey to ascertain the exact amount, cannot be varied by contemporaneous oral agreement that this estimate was to be taken as correct for purposes of tendering the price of the property.19 So a deed of land in which the description is such as to carry future accretions on the side bounded by a river cannot be modified by a prior oral contract that accretions should not pass to the grantee.20 A written contract of employment cannot be added to by showing an oral agreement that the employees should give bond.21 So under a written contract to confess judgment and take a stay of execution, which in law required giving a surety on the stay-bond cannot be modified by an oral contract that no surety should be required.22 So a contract "to deliver to the order of A $800 (less 20 per cent discount) in wall paper at wholesale price," means wholesale price at the time of demand, and an oral provision that the wholesale price fixed by a price card given to the vendee when the contract was made, containing the prices intended, was unenforceable.23 Under a written lease conveying a dining-room situated in a hotel, the lessee agreed to furnish. "board or meals, such as are served to the guests of the hotel, for three persons." This provision in legal effect meant any three suitable persons whom the lessor might designate; and the lessee could not show by oral contemporaneous agreement between himself and the lessor that it meant the housekeeper, the chambermaid and the porter.24 Under a written contract in escrow, by the terms of which A's note was to be delivered to B, when B delivered to A a certain track-laying machine then in the custody of X, who was asserting a lien thereon, A's expenses in getting such machine to be credited upon the note, B could not show an oral contract whereby A promised to take certain steps to obtain this machine from X.25 So a contract giving the right to construct a telephone over A's land generally cannot be shown by oral agreement to be limited to a particular part of the land.26

1 Fisk v. Casey, 119 Cal. 643; 51 Pac. 1077; Nelson'v. Godfrey, 74 Vt. 470; 52 Atl. 1037; Stickney v. Hughes, - Wyom. - ; 75 Pac. 945.

2 Central R. P. v. Hasselkus, 91 Ga. 382; 44 Am. St. Rep. 37; 17 S. E. 838; Loeb v. Stern, 198 111. 371; 64 N. E. 1043; Barney v. Ry., 157 Ind. 228; 61 N. E. 194; Tripp v. Smith, 180 Mass. 122; 61 N. E. 804; Harrow Spring Co. v. Harrow Co., 90 Mich. 147; 30 Am. St. Rep. 421; 51 N. W. 197; Sloman v. Express Co., - Mich. - ; 95 N. W. 999;

Stange v. Wilson, 17 Mich. 342; Liljengren, etc., Co. v. Mead, 42 Minn.. 420; 44 N. W. 306; Irish v. Dean, 39 Wis. 562.

3 Cocker v. Mfg. Co., 3 Sumn. (U. S.) 530; Coates v. Sangston, 5 Md. 121.

4 Brown v. Wiley, 20 How. (U. S.) 442.

5 Gray v. Anderson, 99 Ia. 342; 61 Am. St. Rep. 243; 68 N. W. 790.

6 Brandon Mfg. Co. v. Morse, 48 Vt. 322.

7 West-Winfree Tobacco Co. v. Waller, 66 Ark. 445; 51 S. W. 320.

8 Ferguson v. Arthur, 128 Mich. 297; 87 N. W. 259; Tufts v. Morris, 87 Mo. App. 98.

9 Roberts v. Machine Co.. 8 S. D. 579; 59 Am. St. Rep. 777; 67 N. W. 607.

10 Haynes v. Wesley, 112 Ga. 668; 81 Am. St. Rep. 72; 37 S. E. 990. 11 Hanson v. Gunderson, 95 Wis.

613; 70 N. W. 827. So of a joint chattel mortgage. Williams Bros. Co. v. Hanmer, - Mich. - ; 94 N. W. 176.

12 Powell v. Fraley, 98 Ga. 370; 25 S. E. 450.

13 Tuttle v. Burgett, 53 O. S. 498; 53 Am. St. Rep. 649; 30 L. R. A. 214; 42 N. E. 427.

14 Cook v. Todd (Ky.), 72 S. W. 779.

15 Louisville, etc., JR. R. v. Wilson, 119 Ind. 352; 4 L. R. A. 244; 21 N. E. 341.

16 Drennen v. Satterfield, 119 Ala. 84; 24 So. 723.

17 Abraham v. Ry., 37 Or. 495; 82 Am. St. Rep. 779; 60 Pac. 899.

18 Harrison v. Howe, 109 Mich. 476; 67 N. W. 527.

19 Starin v. Kraft, 174 111. 120; 50 N. E. 1059.

20 Gorton v. Rice, 153 Mo. 676; 55 S. W. 241.

21 Kerr v. Sanders, 122 N. C. 635; 29 S. E. 943.

22 Mayse v. Briggs, 3 Head. (Tenn.) 36.

23 Fawkner v. Wall Paper Co., 88 Ia. 169; 45 Am. St. Rep. 230; 55 N. W. 200.