"Where the matters in issue, involving mathematical calculations, are provable by numerous entries in various official records, it is proper, where the records themselves are before the court, to permit a witness who has examined them to introduce, in connection with his testimony, written statements and computations summarizing the result of his researches." See also Suttle v. Chadwell, 196 Okla. 298, 164 P.2d 880; Bell v. Tackett, 134 Okla. 164, 272 P. 461; Pierce Petroleum Corp. v. Osage Coal Co., 133 Okla. 130, 271 P. 675. No error was committed in the admission of plaintiff's Exhibit 10. Defendant contends that the trial judge was guilty of misconduct so as to indicate an interest in the case and to discredit the defense in prejudice to defendant's rights.
Under these circumstances the reports were admissible in evidence. Pierce Petroleum Corporation v. Osage Coal Company, 133 Okla. 130, 271 P. 675; E.A. Hooven v. First National Bank of Ardmore, 134 Okla. 217, 273 P. 257, 66 A. L. R. 1203; 66 A. L. R. 1206, annotation; 20 Am. Jur. 697, § 831. We therefore hold that the admission of the auditors' reports in evidence was not error, and that the findings of fact by the court were not clearly against the weight of the evidence.
It is, however, equally well settled that an expert who testifies in such case may not state simply that the books show certain facts, but the books themselves must be introduced as primary evidence or their absence satisfactorily accounted for, and the testimony of the expert is secondary and explanatory only. 11 R. C. L. 630; 22 C. J. p. 1017, § 1303. In Pierce Petroleum Corporation v. Osage Coal Co., 133 Okla. 130, 271 P. 675, 676, our Supreme Court said: "It is not error to admit in evidence a digest or statement showing the financial condition and transactions of a company covering a long period of time, prepared by an expert accountant, who qualifies as such expert and testifies that the statement correctly reflects the condition of the company as shown by the books, when the books are all in court and opposing counsel have full opportunity to cross-examine the witness as to the correctness of the statements, and the books are voluminous and such as would require an explanation by an expert accountant."