We agree with the construction of the Building Zone Resolution by the Appellate Division. (211 App. Div. 205.) The determination of the board of appeals was, however, based on an erroneous theory. It did not hear and determine the question under section 20 of the resolution. Proper practice would require that the matter be returned to the board to decide the application of the property owners on the correct theory rather than the Appellate Division should pass on the merits of the application. (People ex rel. Dawley v. Wilson, 200 App. Div. 537; affd., 235 N. Y. 587.)

As it seems clear that the board would exercise its power to vary the provisions of the resolution to the extent of granting the permit now before us under section 20, no substantial right of any party will be affected by an affirmance of the order appealed from.

The order should be affirmed, with costs.

His cock, Ch. J., Cardozo, Pound, McLaughlin, Crane and Lehman, JJ., concur; Andrews, J., absent.

Order affirmed.