— We cannot perceive that tbe court erred in admitting tbe testimony to wbicb tbe plaintiff objected. *755Tbe mortgage from tbe plaintiff to Williams, it is true, bas no connection witb tbis case; and if there bad been no contest as to tbe fact of an over-payment, tbe mortgage would bave been entirely irrelevant. But tbe material inquiry was, whether an over-payment bad been in fact made. Tbis was tbe contested matter of fact, and we think that tbe defendant may show tbe inability of tbe plaintiff to make it; and if be can, of course, every circumstance tending to prove such inability may go to tbe jury, witbou^ regard to tbe weight or influence that may be attached to it. They are to judge of such circumstance ; and although it may amount to little, or even nothing, in their estimation, yet, as it has a tendency to prove a fact that is admissible, we cannot say that tbe court erred in admitting it.
In reference to tbe letter written by tbe plaintiff to McLes-ter, we think it was also admissible. When a plaintiff bas introduced evidence tending to prove a material fact, it is certainly competent for tbe defendant to give in evidence any fact that will impeach or impair tbe weight of tbe evidence thus introduced against him, or that will render tbe truth of tbe material fact more doubtful. Tbis rule of evidence, we think, rendered tbe letter admissible; for we must infer from tbe bill of exceptions, that tbe over-payment, if made at all, was made before tbe letter was written, and it shows that the plaintiff was pressed for money; and also, that, on tbe day before it was written, tbe plaintiff and McLester bad bad an interview, respecting a sum of money which McLester was liable to pay, and yet the plaintiff claimed of him only $322 75. Tbis, of course, is a circumstance tending to prove that, at tbe time tbe letter was written, tbe plaintiff did not know of tbe mistake; and bis being embarrassed in pecuniary matters, and not having discovered tbe mistake for some time after tbe over-payment was made, is a circumstance that may go to tbe jury, to be by them considered in determining whether tbe mistake was in fact made. It is true, that tbe over-payment may bave been in fact made, and it may not have then been discovered; and if tbis were tbe case, then tbe letter could bave no influence witb tbe jury. Yet, in deciding whether tbe over-payment was made, they may take into consideration tbe circumstance that tbe *756mistake was not discovered for a considerable time after it was made. The importance, however, to be attached to that circumstance is exclusively for them.
We have said, that we were bound to infer from the bill of exceptions that the over-payment, if made at all, was made before the letter was written; and we deem it proper to add, that if,' in point of fact, the over-payment was not made before the letter was written, then the letter ought not to be allowed to go to the jury, because, in that aspect of the case, it could tend to prove no legitimate fact or circumstance.
As respects the instructions given by the court to the jury, we do not think they can be sustained as correct expositions of the law. All the authorities agree in this, that if one pay money voluntarily, with a full knowledge of all the facts, he cannot recover it back. I might refer to any number of cases, to show this to be the rule; but I deem it unnecessary, for none of the cases controvert it. But I cannot yield my ^ assent to the proposition, that the means of ascertaining the ¡ real facts of the case are tantamount to actual knowledge of' them. If this were the rule, then it would be but rare that money paid by mistake could ever be recovered back. For instance; if, in the settlement of an account, a mistake in the calculation was made, it could not be afterwards corrected by suit, because the parties, having competent knowledge of figures, had the means of knowledge; and the mistake being the result of negligence, rather than the want of knowledge, the parties would be bound to abide by it.. The recent and best authorities, I think, settle the rule otherwise.
In the case of Kelly v. Solari, 9 Mees. & W. 53, the facts were these: The defendant’s testator had effected an insurance upon his life, but by mistake had failed to pay the last quarterly premium falling due before his death. This was made known to two of the directors of the Insurance Company, and one of them wrote on the policy the word “lapsed.” After the death of the testator, his executor applied for the money; and the directors who had been informed that the policy had lapsed, together with another director, who had not been informed of it, paid the money; and the suit was afterwards brought by the company, to recover it back. On the trial, the two directors who knew all the facts swore, that, *757at the time the money was paid, they had forgotten that the policy had lapsed. Upon these facts, the Chief Baron who presided at the trial, instructed the jury, and directed a non-suit, with leave to move for a new trial. The motion was heard before the Court of Exchequer, and in delivering his opinion the Chief Baron said: “ I certainly laid down the law too broadly to the jury, when I said, that, if the directors once knew the facts, they must be taken still to know 'them, and could not recover by saying that they had forgotten them. I think the knowledge that will disentitle a party from recovering must mean, a knowledge existing in the mind at the time of the payment.” In this opinion the whole court concurred, and the rule for a new trial was made absolute.
The same rule is recognized in the case of Lucas v. Worswick, 1 Moo. & Rob. 293; and in the case of Waite v. Leggett, 8 Cowen, 195, the Supreme Court of New York held, that, to deprive a party of the right to recover back money paid, on the ground of his knowledge that it was not due, it should appear that the money was paid with a knowledge that it was not due; and the fact that the party had the means of knowing that the money was not due, was no answer to the action, provided there was a mistake of fact in the payment.
These decisions, in my judgment, announce the correct rule; and although decisions may be found which indicate a different rule, and that the means of ascertaining the real facts are tantamount to a knowledge of them, yet I cannot yield to them, and I can but think that they are in conflict with the law; for, on examining the eases in which a recovery has been allowed on the ground of a mistake, I will undertake to say, that, in a large majority of them, the party paying had the means within his reach to ascertain the true facts of the case. The court erred in instructing the jury, that, if the plaintiff had the means of knowledge, he could not recover.
The second charge, we think, was also erroneous. When money is paid in consequence of a mistake of fact, the party receiving it is liable for it, as for money had and received for the use of the party who paid it. It is immediately due, and *758the bringing of tbe action is a sufficient demand; or rather, no demand need be made before the suit is brought, to entitle the party to a recovery. See the cases of The Utica Bank v. Van Gieson, 18 Johns. 485, and Hawley v. Sage, 15 Conn. 52.
For the errors in the instructions of the court to the jury, the judgment must be reversed, and the cause remanded.
Note. — This opinion was prepared by the late Chief Justice before his resignation. The court, in its present organization, having fully examined and sanctioned it, Ligoít, J., delivered it as the opinion of the court.
OhiltoN, C. J., did not sit.