¶1By the Court.
¶2The rule of damages in an action on a contract of sale, when the vendor neglects or refuses to deliver the personal property sold, and when nothing was paid by the purchaser, is the difference between the con*17tract price and the market value of the property on the day the property should have been delivered.
¶3The plaintiff’s proof of the value of the stock now in question ought, therefore, to have been confined to the 7th of Hay, when the stock was to be delivered. Upon proof that no sales were made on that day, to the knowledge of the witnesses, their opinions of the value would not necessarily be excluded if they were acquainted with the subject generally, although it appeared, on cross-examination, that their knowledge of actual sales related to a period shortly before or after the day in question. (Dana v. Fiedler, 1 E. D. Smith, 463.)
¶4But a plaintiff, on direct examination, is not at liberty to prove sales after the time of delivery as a ground for an inference by the court or jury, that the value of the property was the sum at which such sales were made.
¶5There was evidence in the cause upon which (had that alone been received for consideration) the finding of the court below might, we think, have been supported, as not being without evidence; but when illegal evidence is, in fact, received, and the return states, in terms, that the finding of the court below is upon a consideration of all the evidence given upon the subject, we are not at liberty to disregard the error. In such case, it not only appears that the improper testimony may have influenced the court in its finding upon the facts, but that it did so.
¶6The judgment must be reversed, with costs.
¶7Judgment reversed.