Under the instructions given to the jury, their verdict for the defendants imports, not merely that the article which was sold to them was not such as it was warranted to be, but that they were misled and deceived by false representations. The jury must have found that the plaintiff’s agent, Wilcox, informed the defendants, in substance, that the heater, if attached and operated according to the printed directions, would substantially prevent the transmission of oil to the boilers. This was the quality upon which its whole value depended, and it was this assurance, as the defendants contended, which induced them to make the purchase. In order to prove that this representation was false, they were permitted to show that other heaters made and sold by the plaintiff, identical in them construction with that which it had sold to the defendants, necessarily transmitted oil to the boilers in injurious quantities. Under the carefully guarded ruling of the court, the jury must have found that this failure in the operation of the mechanism was not caused by any defect or negligence in the setting or operating, and was not merely accidental or of occasional recurrence, but that it was the necessary and inevitable result of the construction of the mechanism itself. If it had been ascertained that the plaintiff’s heaters, exactly like the one which they had sold to the defendants, were incapable from their very construction of doing what was promised, and that they must of necessity fail in the exact particular which had been urged and relied upon as their chief merit, there was no occasion for the defendants to go through the ceremony of putting that particular one to the test of actual experiment. The jury must have found, under the instructions, that the plaintiff’s agent made such representations; that thej were false, and that he knew them to be false at the time.

*447The defendants’ answer raised an issue of fraud, and upon that issue the evidence admitted was competent and appropriate. Such a fraud, if proved, would avoid the contract of sale. Pike v. Fay, 101 Mass. 134. In Vale v. Butler, 111 Mass. 55, relied upon by the plaintiff, the case raised the question of warranty only, and not of deceit. Exceptions overruled.