Sec 181

An essential error as to the subject matter of a bargain may prevent the inception of a contract in the following cases:-

1. When a party undertakes to alienate that which is unalienable.

2. When he buys something belonging to himself, supposing it to belong to another.3.

3. When he gives in delivery another person's goods instead of his own ; though in such case, if the error is not as to identity but as to title, the contract is good, and he must respond in damages if the thing be recovered from his vendee.4.

And so as to error as to subject matter.

1 Benj. on Sales, 3d Am. ed. sec 58.

2 Mudge v. Oliver, 1 Allen, 74; see Boston Ice Co. v. Potter, 123 Mass. 28.

3 Leake, 2d ed. 341; Bingham v. Bingham, 1 Ves. Sen. 126 ; Cochrane v. Willis, L. R. 1 Ch. 58 ; Jones v. Clifford, L. R. 3 Ch. D. 779. " A stipulation to purchase one's own property is 'naturali ratione inutilis,' as much as if the thing was destroyed, or not capable of being private property." Pollock, Wald's ed. 127. Cases of agreements held void on the ground that the parties were mistaken in holding that the estate of one of them was materially burdened in a way in which it was not burdened, will be found in Cooper v. Phibbs, L. R. 2 H. L. 149; Broughton v. Hutt, 3 De G. & J. 501. To the same effect Mr. Wald (Wald's Pollock, 428) cites Jordan v. Stevens, 51 Me. 78 ; Martin v. McCormick, 8 N. Y. 331. In Pennsylvania conveyances in mistake of rights have in like manner been set aside. Leek v. Cowley, 10 S. & R. 176 ; Allen v. McMasters, 3 Watts, 181 ; Horbach v. Gray, 8 Watts, 492 ; Gross v. Leber, 47 Penn. St. 520 ; Huss v. Morris, 63 Penn. St. 367; Russell's App., 75 Penn. St. 269. Though it is otherwise when the mistake is as to a general principle of law. Infra, sec 198; Good v. Herr, 7 W. & S. 253; Meckley's Est., 20 Penn. St. 478 ; Mc-Aninch v. Lauglin, 13 Penn. St. 371 ; Gross v. Leber, 47 Penn. St. 520. Under this head may be considered cases of impossibility of performance, hereafter discussed. Infra, sec 296 et seq.

In Peters v. Florence, 38 Penn. St. 194, relief was refused to a party paying off a mortgage in mistake of his own liability ; though this case may be gravely questioned.

4 Infra, sec 230; Koch, ut supra, citing L. 16, pr. D. eod. ; L. 10, C. eod.; L. 35, D. de acqui. rer. dom. (41, 1).

4. When he pays money under a mistake of fact; in which case, by both the Roman and our own law, the money paid may be recovered back.1.

5. When he buys personal property to which the vendor has no title; in which case, by our own law, the vendee may treat the contract as a nullity.2 And in all cases of sale or bailment, " a common mistake of this kind may be available for rescinding the conveyance after completion of the contract, although, in general, after completion, the only remedy of a purchaser, in respect of title, is upon the covenants of title, if any, given by the vendor."3.

6. When a party receives as a gift what the other party meant as a sale, he not being informed that the article was sent to him to be bought by him, and honestly and non-negli-gently believing it to be a gift.4 "If A. sends a case of wine to B., intending to sell it, but fails to communicate his intention, and B., honestly believing it to be a gift, consumes it, there is no ground for holding B. to be responsible for the price either in law or equity, if he be blameless for the mistake."5.

7. Where a party sells under a non-negligent essential mistake as to the character of the thing sold.6 This is eminently the case when the party selling has been imposed upon, either intentionally or unintentionally, by others.7 Thus equity will give relief in cases where aged and infirm persons are induced by erroneous information to sell property at a price far below its value.8.

1 Bell v. Gardiner, 4 Man. & G. 11; Kelly v. Solari, 9 M. & W. 54; Waite v. Leggett, 8 Cow. 195 ; Wheaden v. Olds, 20 Wend. 174 ; Mayor of N. Y. v. Erben, 38 N. Y. 305; infra, sec 186, 520, 742 et seq.

2 Infra, sec 230; Story on Contracts, sec 533 ; Allen v. Hammond, 11 Peters, 63 ; Bradeen v. Brooks, 22 Me. 463.

3 Leake, 2d ed. 341, citing Bingham v. Bingham, 1 Ves. Sr. 126; Clare v. Lamb, L. R. 10 C. P. 334; Hart v. Swaine, L. R. 7 C. D. 42. See to same general effect Montgomery Co. V. Am.

Emigrant Co., 47 Iowa, 91; Burkham v. Daniel, 56 Ala. 604, and cases cited infra, sec 191.

4 Infra, sec 199.

5 Benj. on Sales, 2d Am. ed. 373, adopted in Pollock, Wald's ed. 407. The question of error in law, as ground for relief, is independently discussed in a succeeding section (infra, sec 198).

6 Infra, sec 187 et seq.

7 Svpra, sec 161 ; infra, sec 214.

8 Supra, sec 165 ; Mason v. Pelletier, 82 N. C. 40; Dalton v. Dalton, 14 Nev. 419.