Even if an offer is intended to create legal relations, it must be so complete that its terms will enable the court, with the aid of admissible extrinsic evidence, to determine what obligation is imposed upon each party and whether such obligation has been performed.1 Contracts of these classes shade imperceptibly into contracts in which the parties have entered into covenants as to each of the matters involved in the transaction, but one or more of such covenants is so vague or indefinite that it can not be enforced.2 A contract may be incomplete because the parties have intended to leave certain terms to be settled by subsequent negotiations;3 or because the parties have not in fact agreed upon all the essential terms of the contract, though they may not realize that certain terms are omitted.4 If a contract is complete upon its face and shows that the parties have agreed upon all the essential elements thereof, it will not be presumed that there were other accidental terms upon which the parties agreed, but which they have omitted.5 If the contract can take effect and can be performed it will not be presumed that the parties had intended to incorporate into their contract other terms to be agreed upon thereafter; even if such terms might well be a part of such contract.6 A contract which, on the other hand, shows on its face that the parties have not agreed upon one of the essential elements thereof is invalid, whether the parties have intended to leave such omitted terms to be settled by future negotiations,7 or whether they have omitted them through failure to realize their necessity,8 or whether they believe that the vague and indefinite covenants of their contract are sufficiently definite and certain.9

11 Walsh v. St. Louis, etc., Association, 90 Mo. 459, 2 S. W. 842.

12 Carlill v. Smoke Ball Co. (1893), 1 Q. B. 256, 67 L. T. N. S. 837.

13 Texas, etc., Ry. Co. v. Ludlam, 57 Fed. 481, 6 C. C. A. 454.

14 Kellerman v. By. Co., 136 Mo. 177, 34 S. W. 41; affirmed in banc, 37 S. W. 828, affirming 68 Mo. App. 255.

1 England. Winn v. Bull, L. R. 7 • Ch. Div. 29.

United States. Peoria Grape Sugar Co. v. Babcock Co., 67 Fed. 892.

Alabama. Bissenger v. Prince, 117 Ala. 480, 23 So. 67.

California. Santa Rosa, etc., Co. v. Woodward, 119 Cal. 30, 50 Ac. 1025.

Florida. Etheredge v. Barkley, 25 Fla. 814, 6 So. 861.

Illinois. Almini Co. v. King, 92 111. App. 276.

Kansas. St. Louis & S. F. R. Co. v. Gorman, 79 Kan. 643, 28 L. R. A. (N.S.) 637, 100 Ac. 647.

Maryland. Wills v. Carpenter, 75 Md. 80, 25 Atl. 415.

Massachusetts. Sibley v. Felton, 156 Mass. 273, 31 N. E. 10.

Mississippi. Rector Provision Co. v. Sauer, 69 Miss. 235, 13 So. 623.

Missouri. Kelly v. Thuey, 143 Mo. 422, 45 S. W. 300 [reversing in banc 37 S. W. 516].

New Hampshire. New England Box Co. v. Prentiss, 75 N. H. 246, 72 Atl. 826.

New York. Schenectady Stove Co. v. Holbrook, 101 X. Y. 45, 4N.E.4; Brauer v. Oceanic Steam Navigation Co., 178 N. Y. 330, 70 N. E. 803.

North Carolina. Elks v. North State Ins. Co., 159 N. Car. 619, 75 S. E. 808.

Oregcn. Holtz v. Olds, 84 Or. 567, 164 Ac. 5S3 [rehearing denied, Holtz v. Olds, 84 Or. 567, 164 Ac. 1184].

Tennessee. St. Paul, etc., Ins. Co. v. Ulbright (Tenn. Ch. App.), 48 S. W. 131.

Washington. Meacham v. Pederson, 70 Wash. 479, 127 Ac. 114.

Wisconsin. Mattoon, etc., Co. v. Insurance Co., 69 Wis. 564, 35 N. W. 19.

2 See Sec. 95 et seq.