Opinion by

The appellees entered into a contract with the borough of Homestead for the construction of a reservoir. It provided that they were to do all the work and furnish all the materials called for by this agreement in the manner and under the conditions hereinafter specified.” The terms of the specifications were plain and unambiguous, and the contractors knew just what was required of them. The nature and kind of work to be done and the materials to be furnished by them were set forth in detail. The contract was entered into in June, 1891, and the work completed about a year afterwards. On July 16, 1892, estimate No. 11, the last furnished by the engineer, showed the amount due the contractors, from which the sum of $2,000 was to be withheld until the completion of the reservoir. At that time the appellees contend that the reservoir was completed in accordance with the terms of their contract, and that the said sum, instead of being withheld, should have been paid to them. On the other hand, appellant insists that there can be no recovery by the contractors in view of the obstacles found in the contract itself. This was the question considered and passed upon by the court below in entering judgment for the plaintiffs on the special verdict rendered by its direction, and we are now called upon to dispose of the two assignments of error, which are as follows :

1. In refusing defendant’s point which was as follows, that, u under all the evidence, the plaintiffs are not entitled to recover.”

2. The court erred in charging the jury as follows : “ Under the law and the evidence in this case we are of the opinion, and so instruct you, that the verdict must be in favor of the plaintiffs; and we therefore direct you to find a verdict in favor of the plaintiffs in the sum of $2,000, with interest from July 16, 1892, subject to the opinion of the court on the question of law reserved, which is whether there is any evidence which entitled the plaintiffs to recover.”

The appellant resists payment because (1) the contractors were bound under their contract to make a water tight reservoir ; (2) there can be no recovery until an estimate is made by the engineer, and (3) there can be no recovery because of the arbitration clause, which makes the decision of the engineer final and conclusive.

*60There is nothing in the contract binding the contractors to construct a “ water tight ” reservoir. They were simply to do certain work in accordance with definite plans and specifications, but they bound themselves to no results. It is true that the specifications provided that “ the work contemplated .... is the construction of a water tight reservoir; ” and the engineer by whom they had been prepared evidently thought they would produce such a result, but the contractors assumed no such responsibility. Their contract with the borough of Homestead was to construct a reservoir in accordance with the plans and specifications, and if they had done so at the time they brought their suit, a recovery cannot be defeated simply because the reservoir was not water tight, and results contemplated by the engineer had not been realized. This was the view taken by the learned judge in the court below, in which we concur. As was said in Filbert v. Phila., 181 Pa. 545, so it can be repeated here, “ The contractors were given no discretion. Every line was drawn, every grade was fixed, and every detail was provided for by the city.”

In estimate No. 11, made by the engineer, the amount due to plaintiffs under the terms of their contract and unpaid was shown to be $20,552.90. From tins amount was retained the sum of $2,000 until the' completion of the reservoir. That estimate shows the amount due on 'the contract, and if the work was then completed the borough of Homestead could not lawfully withhold the $2,000 from the contractors; and we again concur with the trial judge that the plaintiffs were entitled to their money at the time the estimate was made, if their contract was really the neompleted, all of which was for the consideration of the jury.

As to the third reason why there should be no recovery, we cannot sustain the view taken by the defendant, for the engineer was to determine the amount and quality of work done and to decide questions relative to the execution of the contract. As it was not shown that the leakage was due to any failure on the part of the contractors to fully perform what they had undertaken to do, we do not feel that the borough of Homestead had a right to invoke that clause of the contract. The first assignment of error is therefore overruled.

We cannot, however, approve the binding instructions of the *61court directing the jury to find a verdict in favor of tlie plaintiffs. Whether they had fully performed the contract entered into by them with the borough of Homestead was purely a question to be determined by the jury. It is true that the defendant offered practically no testimony, but nevertheless it was for the jury to decide, even if the plaintiffs and their witness did testify that the contract had in every particular been performed, whether this was true, and the court should not have peremptorily instructed a finding in their favor. In Grambs v. Lynch, 20 W. N. C. 376, it was held that the question of the credibility of a witness cannot be taken from the jury. It is their duty to credit him if there is no good reason to the contrary ; but Ins mere manner may discredit him, and his story may be so against all the probabilities of the case that a jury may be justified in not believing him. ín that case Mr. Justice Paxsox says: “It is settled law that where a case depends upon oral testimony such testimony must be submitted to the jury.” In the case before us this rule certainly ought not to have been relaxed. We feel that it ought to be retried, with instructions from the court that if the testimony offered by the plaintiffs be believed by the jury, their verdict should be against the defendant. The second assignment of error is sustained and the judgment reversed, with a venire facias de novo.