It appears upon the facts reported that the articles which the plaintiff had furnished were recommended on the ground that they would make a saving in the fuel consumed of as much as twelve per cent. The question whether they would do so was agreed to be left to be decided upon actual experiment by the defendant’s engineer. ■ It is reported as a fact found by the court, sitting without a jury, that the experiment was tried by the engineer, and showed a saving exceeding twelve per cent. His decision was rendered accordingly, and is to be considered as the award of a referee under a submission to arbitration. In the absence of any suggestion of fraud, this award cannot be impeached on the ground of any error in judgment on *146his part, in drawing conclusions from the evidence before him. The case falls within the rule laid down in Palmer v. Clark, 106 Mass. 873, 389, and Flint v. Gibson, 106 Mass. 391.

Exceptions overruled.