Opinion by

The policy stipulates that the insurance under it shall begin at noon and expire at noon of the days named. Such an agreement is entirely lawful and, of course, becomes the special rule for the fixing of dates so referred to. But it is by no means clear that it is intended to apply as the rule for all computations of time under the policy. The object of the clause is to fix with precision the term covered by the insurance and thereby to avoid possible dispute on the fundamental basis of any liability for loss. The same reason does not apply with equal force to the question of time on collateral matters, such as the stipulated protection for five days of property removed on account of danger of fire, the sixty days after adjustment of amount when the loss is to become payable, or the five days’ notice of cancelation as involved here. The application of such a special rule for computation might be extremely inconvenient and doubtful, as for example if goods had been removed in this case to save them *260from the fire, starting at 10:80 p. M. on April 12, what period should the five days’ special protection cover? From noon of the 12th to noon of the 17th would afford the insured less actual time than he was entitled to, while from noon of the 13th to noon of the 18th would give him more. The result would be no more accurate than by the application of the general rule of excluding the first day and counting the days as legal days beginning and ending at midnight. This method, disregarding fractions of a day, is the general rule, and would appear to be the better construction of the policy in suit. But all question in the present case is obviated by the absence of any evidence or averment in the affidavit of defense of the hour on April 7 when notice of cancelation was given to the plaintiff. The first .assignment of error is overruled.

But the other assignments must be sustained. The affidavit of defense sets up clearly and specifically in the established and approved form that defendant “ is informed, believes and expects to be able to prove ” that the plaintiff’s loss in respect of equipment was not $228,734 as claimed but did not exceed $60,000, and the amount of defendant’s liability, if liable at all, was not $2,099 as claimed in the statement but would not exceed $1,035. This was sufficient to prevent judgment and put the plaintiff to proof of the amount of its loss. The plaintiff relied on the appraisement, but that is never conclusive, and is not even evidence at all unless made so by the parties uniting in it. It gets its entire force from the joint act of the parties through their agents, and where it is ex parte and, though averred by plaintiff in his statement, is denied by defendant, it goes for nought and is not evidence at all either on the motion for judgment or at the trial.

But the court below was of opinion that by defendant’s refusal to join in the appointment of appraisers, coupled with a total denial of liability, defendant was estopped from disputing the amount of the loss as estimated by appraisers appointed by other insurance companies and by plaintiff, ex parte as regards this defendant. This was a serious error. There was no element of estoppel in such action. The policy provides that, in case of disagreement as to the amount of loss, it shall be ascertained by appraisers, and further that no action shall be brought on the policy until after compliance with all its requirements, *261among which is that relating to appraisers. Such appraisement or the effort to have it would be at the most a condition precedent to an action by the insured, and the failure to have it a ground for a plea in abatement by the company. Refusal to join in the appointment of appraisers, or denial of liability altogether, either or both, would estop the defendant from such a plea, but it could go no further. The provision of the policy in this respect raises a preliminary question for the court in the' same manner and with the same limited effect as the analogous question of proofs of loss, which is discussed and determined by our Brother Dean in Cole v. Fire Assurance Co., 188 Pa. 845. Neither appraisement nor the technically so-called “ proof of loss ” is of itself competent evidence of the fact or amount of loss except as against a party who has made it his own act by joining in it.

But it has been held that the condition of the policy as to appraisement before suit is in substance no more than an undertaking to refer to arbitrators to be chosen in the future, and therefore revocable. Suit by the insured without preliminary appraisement has been sustained because the agreement being revocable could not bind him: Mentz v. Ins. Co., 79 Pa. 478; Commercial Union Assurance Co. v. Hocking, 115 Pa. 407; Yost v. McKee, 179 Pa. 381. The same rule must apply to the other party to the contract, and therefore if the defendant company omits or refuses to join in an appraisement, its rights cannot be prejudiced thereby, and it certainly cannot be es-topped by a denial of liability from requiring that if its liability is established, the amount of it shall be proved by competent evidence.

The learned judge below refers to McCormick v. Ins. Co., 163 Pa. 184, but that case falls far short of sustaining the present judgment. .If a defendant by his action misleads the plaintiff as to a certain line of defense he may be estopped from bringing forward that defense at the trial, but he is not thereby estopped from requiring the plaintiff to prove the ground on which he is allowed to recover. The principles by which the subject of waiver by estoppel, in regard especially to insurance companies, is governed, were carefully considered and intended to be settled in Gould v. Ins. Co., 134 Pa. 570, and the authority of that case has been affirmed in Everett v. Ins. *262Co., 142 Pa. 332, Whitmore v. Ins. Co., 148 Pa. 405, Freedman v. Fire Assn., 168 Pa. 249, Freedman v. Ins. Co., 175 Pa. 350, and other cases. In the last mentioned it was said by Fell, J.: “ In most of the cases in which it has been held that an insurance company by specifying one ground of defense was estopped from asserting other grounds at the trial, the failure of the insured has been in not complying with a condition precedent to the right of action, and they came within the rule stated in Gould v. Insurance Co., or were decided upon the ground of express waiver. In McCormick v. Royal Ins. Co., by mutual understanding of the parties, the only matter in controversy between them was the ownership of the property destroyed; all other grounds of defense had been relinquished. Suit having been brought with this understanding to determine the question of ownership, and nothing else, it was held that the company could not' be permitted to defend on the violation of a clause in the policy regulating the manner in which the lumber should be stored.” In the very numerous cases of this class upon insurance policies, most of them as said by our Brother Fell, supra, turning on technical defenses upon conditions precedent to the right of action, there are no doubt some in which there is room for difference of opinion as to the application of the principles laid down in Gould v. Ins. Co., but in no case has there been any effort or intention to change or impair those principles as the guide to decision. The judgment in the present ease is far outside of the rule there laid down.

Judgment reversed and procedendo awarded.