It was held in Callan v. Lukens, 89 Pa. 134, that there is no rule that a supplemental affidavit of defense is to be confined to an explanation of the original, and cannot set up a new and different defense; such a course, however, is suspicious and requires that the new defense should be closely scrutinized. This is especially to be observed where the affidavits are contradictory, as they are in this case. The first affidavit avers that the portion of the plaintiff’s account, for which payment has not been made, is not for “merchantable roofing slag,” as the contract stipulated, but for what is called in the trade *625“three fourths slag,” a commodity not salable, and for that reason the defendant had declined to pay for it. The second affidavit avers that a certain quantity of the slag delivered under the contract, although suitable for paving and used by the defendant for that purpose, was inferior in quality to roofing slag, and of less value, and that he had paid the plaintiffs more than the market value. These two affidavits cannot be dovetailed; but assuming, as we may, that the second was intended to present the whole defense, the court properly adjudged it insufficient. An affidavit of defense should state the facts specifically and with sufficient detail to enable the court to say whether they amount to a defense, and to what extent they amount to a defense, and also to inform the plaintiff with some degree of certainty what will be interposed to defeat his claim. The affidavit fails to meet these plain requirements. It does not state the quantity or value of the slag that was inferior in quality; it may have been a ton or it may have been a carload. It was within the defendant’s power to state these facts specifically, and according to the uniform construction of the affidavit of defense law it was his duty to do so. An averment that the defendant “ suffered business inconvenience, and a greater loss than claimed ” is too vague to prevent judgment.