Opinion by

There is no doubt that when a letter is properly addressed and mailed with postage prepaid, there is rebut-table presumption of fact that it was received by the addressee: Phoenix Brewing Company v. Weiss, 23 Pa. Superior Ct. 521, and this presumption is strengthened when there is on the envelope a notice to return to the sender if not delivered. The defendant’s affidavit avers that, on or about May 1,1917, the letter in question was duly mailed. The letter was dated May 1, 1917, but the date of the letter authorizes no inference that it was mailed on said date: Phelan v. Northwestern Mut. L. Ins. Co., 113 N. Y. 147; Uhlman v. Arnholdt, Etc., Brewing Co., 53 Fed. 485 (16 Cyc. 1069). “On or about” is an indefinite term which, under the circumstances of the case does not suffice.

The plaintiff’s claim is for merchandise furnished from May 5,1917, to June 5,1917. The defendant’s guarantee continued under its original terms until the alleged modification was received by the plaintiff. Conceding that defendant did send the letter how is the court to determine as to what items of the claim the defense applies? If the defendant was uncertain as to the time, he could have avowed his inability to fix the precise date but could have asserted that the letter was mailed prior to a date of which he was certain, and thus the court could know as to what part of plaintiff’s claim the defense applied.

We think the affidavit is insufficient, in that the place of the mailing and the time required for transmission are not stated. In a case like this where the time of receipt is so important these should appear.

The judgment is affirmed.