The precise question involved in this appeal has been determined by our recent cases of Commonwealth, to use, v. Hartford Acc. & Ind. Co., 306 Pa. 513, and Commonwealth v. R. L. Bonham Co., 297 Pa. 514, where it is stated at page 518: “A surety is not liable on the bond unless it appears the unpaid work was done pursuant to the contract the bond purports to cover.”

Judgment affirmed at appellants’ cost.