The defendant on July 26, 1920, bought of the plaintiffs through brokers two carloads of potatoes, and received a duplicate or confirmation memorandum of sale, signed, “Atlantic Brokerage Company,” the material terms of which read: “ . . . *186you have bought, and Rooney & Ely, Englishtown, New Jersey, has sold to you through us, acting as brokers Two carload of Jersey potatoes. Cost $6.00 per 150 pound sack f.o.b. loading station. Grade United States Number One. Quality Good. Shipment Monday, July 26, 1920. Route Boston, Mass., New York, New Haven & Hartford delivery. Terms Regular. Order received via Mr. McLeod. Order placed via Telephone. Remarks: We consider the above memoranda covers this order fully, and we are mailing this to you, a copy to the seller, retaining one ourselves.” The plaintiffs on July 26, 1920, shipped the two carloads hereafter referred to as car one and car two. The bill of lading for car one issued by the Pennsylvania Railroad Company was marked “Straight Bill of Lading — Not negotiable consigned to Rooney & Ely advise Newsom & McLeod,” the trade name under which the defendant did business, and was also marked "Abnormal conditions prevail on the lines of the carrier which will handle this shipment and it is subject to delay.” The bill of lading of the second car was on the same form as that of the first car with a notation “subject to delay,” but bore no indorsement by the plaintiffs and the defendant. The plaintiffs forwarded both bills to a national bank at Boston with drafts for the price attached; and the bill of lading of the first car produced at the trial by the company was indorsed on the back by the plaintiffs and the defendant. On July 29, the defendant, upon being informed of its arrival, directed his bookkeeper to go to the bank and pay the draft on the first car which was then being unloaded. But, through some oversight, he paid the draft on the second car which had not yet come in. The defendant, upon discovery of the error, notified the brokers that the “Bill of Lading read ‘subject to delay,’ which he did not know of,” and asked them to notify the plaintiffs which they did on August 2, 1920. He also wrote the plaintiffs that the second car “billed to you flat” had not arrived and “You had a car billed open and our bookkeeper intending to pay the draft on that car, paid it on this car by mistake, therefore, we have held up the paying of the draft, on that car that was billed flat owing to this not arriving. We notice the bill of lading of this car reads subject to delay, and you billed the car to yourselves. Now, you better get after the railroad and make disposition of the car. Doubtless if it ever reached Boston, and if it does, no doubt will *187be in poor condition.” A bill was enclosed showing the amount of the draft on the first car with a credit of the invoice, to “rectify the error in appropriation of this payment,” leaving a balance of “sixty dollars” payment of which was demanded. The second car arrived on August 6, and, the defendant having notified the brokers, they wrote the plaintiffs that the defendant “advised us that he has paid the draft on that car by mistake and so informed you, and that he intended to pay on the car he unloaded.” The defendant, after notice from the carrier acting under instructions from the plaintiffs, that the second car would be delivered to him, declined to accept, and under directions from the plaintiffs the bill of lading was delivered to a third party. While these transactions were pending, the potatoes had been sold by the carrier as perishable freight, and the proceeds were in its possession at the date of the trial.

But, even if the bookkeeper had been instructed to pay for the first car, (and in what way he obtained both bills of lading is not disclosed,) it is plain, indeed the facts are not in dispute, that the defendant accepted, and took possession of the potatoes shipped in the first car, to recover the price for which this action is brought. See G. L. c. 108, § 12. Forbes v. Boston & Lowell Railroad, 133 Mass. 154, 157, 158. The shipments were to be paid for as each car arrived, under its own bill of lading, and the error of mistaken identity cannot in any way be attributed to the plaintiffs. If by shipping the potatoes the plaintiffs appropriated them to their bargain with the buyer, yet the bill of lading was not to be delivered until payment of the draft, and the defendant with knowledge of his mistake continued to exercise the rights of an absolute owner, and dealt with the property as his own. The plaintiffs, who should not be deprived of compensation because of his inadvertence, can waive the precedent condition of payment which was attached only for their own security, and treat the title as having constructively passed, and recover the price. Merchants’ National Bank of Cincinnati v. Bangs, 102 Mass. 291, 295. Libby v. Ingalls, 124 Mass. 503. Wright & Colton Wire Cloth Co. v. Warren, 177 Mass. 283. Williston on Sales, §§ 283, 284. G. L. c. 106, § 52 (1). Bellows v. McKenzie, 212 Mass. 601, 604. Bristol Manuf. Corp. v. Arkwright Mills, 213 Mass. 172.

The evidence offered by the defendant to prove a custom of the *188trade with reference to the acceptance of a bill of lading, and to explain the meaning of the phrase “terms regular,” or the word “regular” found in the memorandum of sale, or “subject to delay” in the bill of lading, or to show how long a shipment of new potatoes in July or early in August would last without deterioration, or would show spots in a very short time, or the course of the market, or “what further did you do with reference to notifying the defendant,” was excluded rightly. The mutual obligations of the parties, if any, as to the second shipment were not in issue, and, the defendant having taken and kept the first shipment without making any claim for reclamation, the inquiries as to that shipment were immaterial. Trimount Lumber Co. v. Murdough, 229 Mass. 254.

The defence of payment is unsupported by the record. Endicott-Johnson Co. v. Simpson, 206 Mass. 14.

The defendant’s first, second, third, fourth, sixth, seventh and eighth requests, which related wholly to the second car, and the fifth request, that, the defendant having intended to pay for the first carload, notice of which having been given to the plaintiffs, the transaction amounted to payment of the first draft, could not have been given for reasons just stated.

The verdict for the plaintiffs having been properly directed, the exceptions should be overruled.

So ordered.