In determining whether the jury should have-been unconditionally instructed to find for the defendant on the ground of estoppel, it must be assumed that the payment by the bank to whoever received it was without authority and in its own wrong. The certificate was payable-to the order of the plaintiff, on its return properly indorsed. It was the defendant’s duty to observe the terms of the certificate and make payment only in accordance with them, and the plaintiff had a right to assume that it would act accordingly. Evidently, the deposit was in the nature of an investment to obtain the stipulated interest on the amount;, and the plaintiff, having obtained the certificate and put it away in a place of supposed safety, had but little occasion to-examine it, much less than he would have had if the deposit: had been in the form of a pass book periodically balanced, the vouchers of payment being returned. In this respect the case is more favorable for the plaintiff, and there was less ■ frequent occasion for scrutiny; but if the transaction had been in the latter form, and the plaintiff had been charged with improper items in his account, and it had been balanced on the basis of such charges, the account could have-been impeached and readjusted by proof of fraud or mistake.. *73Weisser's Adm'r v. Denison, 10 N. Y. 68, 82; Frank v. Chemical Nat. Bank, 84 N. Y. 213; Shipman v. Bank of State of N. Y. 126 N. Y. 327; Conville v. Shook, 144 N. Y. 688. As ■was said in the former case: “ The duty and the risk of ascertaining, when it was about to pay out money, that it was being paid upon competent authority, was upon the bank, just as it is in all other cases upon the debtor to see to it that he pays his creditor and not some one else without authority.” The plaintiff had not done anything to mislead or deceive the defendant, nor had he conferred upon any one an apparent right or authority to receive the money in dispute. The defendant does not produce any written authority, nor is there any testimony showing the terms of any verbal authority, or who made pretense of any, and it is unable to name the person to whom it paid the money. The transaction was not only unauthorized by the terms of the certificate, hut it was contrary to the well-understood course and usages of bankers. Had the plaintiff first discovered the unauthorized payment the next day after the $200 certificate had been issued to him, it is impossible to say that he would not have been entitled to have the improper credit canceled and the certificate corrected; but the claim is that he is absolutely estopped by having retained this certificate, as well as the former one upon which the in-dorsement of September 7, 1891, was made, so long without objection; that he had slept on his rights; and that by reason of his negligence he is barred 'of his right to recover his money, wrongfully paid out to some unknown person.

The estoppel relied on depends upon proof of negligence on his part, by which the defendant has been or may be prejudiced in reclaiming the money if he is allowed to maintain his claim. The question of negligence is one of fact, depending upon inferences properly to be drawn from the evidence and the peculiar circumstances of the case, even though there is no serious conflict of testimony; and whether he was negli*74.gent or not is not merely a question of law for the court, 'but a mixed question of law and fact for the jury, under proper instructions from the court. This was so held in Leather M. Bank v. Morgan, 117 U. S. 98-100, 122. In that •case it is said: “ It seems to us that if the case had been submitted to the jury, and they had found such negligence upon the part of the depositor as precluded him from disputing the correctness of the account rendered by the bank, the verdict could not have been set aside as wholly unsupported by the evidence. . . . While no rule can be laid down that will cover every transaction between a bank and its depositor, it is sufficient to say that the latter’s duty is discharged when he exercises such diligence as is required by the circumstances of the particular case, including the relations of the parties and the established and known usages of banking business.’’ Janin v. London & S. F. Bank, 92 Cal. 11; Shipman v. Bank of State of N. Y. 126 N. Y. 327-329, .and cases above cited.

The evidence shows that the plaintiff could neither read nor write, and that his wife could read but little and could not write; that she could make out little from plain writing, .and that they were careful and cautious in respect to the ■custody of the certificate, and, if it got into unauthorized hands, it was not through any want of care or caution on their part; that the plaintiff did not know of the unauthorized payment until about fourteen months after it was made; that, although made about three months and a half before the $200 certificate was issued (December 21, 1891), it does not appear that at the latter date anything was said or suggested about any payment or indorsement. The case is between the original parties to the transaction, and the defendant has no right to claim the benefit of a mistake, apparently wholly its own fault, and to insist that the plaintiff ■shall lose his money, unless there is reason to find or infer from the evidence that the plaintiff, after the wrongful pay*75ment and indorsement, was guilty of negligence in not discovering and informing the defendant óf the fact, whereby it has been or may be prejudiced. The request that the jury .•should be instructed to find for the defendant was properly ■denied.

If the defendant had desired other or fuller instructions, it should have asked for them. The instruction given on this subject was excepted to, bub it cannot be said that it was •erroneous, the court having told the jury that they might take into consideration the fact that he could not read or write, that he never examined the papers, and did not know what was in them; and that his wife was a poor reader, and never read them,- — -“as tending to explain and break the force of his holding them so long without saying anything about the discrepancy.”

Ve .are unable to say that, upon the facts proved, there ■could properly be any inference drawn by the jury that the defendant had been or might be prejudiced by the failure of the plaintiff to make earlier discovery and communication of the improper payment. Had he discovered and communicated it when he obtained the $200 certificate, about three months and a half after the indorsement was made, there is nothing to indicate that the bank would have then been able to ascertain to whom it had paid the money, or that it would probably have been in any better position than when the plaintiff first claimed that the payment was wrongful. The defendant was bound to make out its case by proof and reasonable inferences from it. A mere possibility, conjecture, or surmise that it would have been in a better position will not suffice. Janin v. London & S. F. Bank, 92 Cal. 14, 27. This is not in conflict with what was held in Leather M. Bank v. Morgan, 117 U. S. 115, in which it was said that, to make out the defense, “ it is sufficient if it appears that the bank, by reason of the negligence of the depositor, was pre*76vented from promptly and, it may be, effectively ” exercising its remedies to compel restoration and payment. Judgment was properly given for the plaintiff.

By the Court.— The judgment of the circuit court is affirmed.