The petitioner is a hnilding contractor, and the Board found that he kept his books on the completed contract method and made his returns accordingly. Section 212 (b) of the Revenue Act of 1921, 42 Stat. 237; article 36b, Treasury Regulation 62. There is evidence to support these findings of fact. The contention that article 36 was invalid because inconsistent with the accounting periods is without merit. It provides a method of determining income attributable to each animal period. It is a valid regulation. Burnet v. Sanford & Brooks Co., 282 U. S. 359, 51 S. Ct. 150, 75 L. Ed. 383; Bent v. Commissioner, 56 F.(2d) 99 (C. C. A. 9). Wo may accept the finding of the Board that the petitioner kept his books on the completed contract basis. The Board had the opportunity to examine the petitioner’s books, and, having rekehed the conclusion it did, we must give effect to its findings. Phillips v. Commissioner, 283 U. S. 589, 51 S. Ct. 608, 75 L. Ed. 1289. Upon the facts as found, the conclusion of the Board must be affirmed.

Order affirmed.