It is a mere offer or proposal by the plaintiffs that the defendant should accept the proposed contract inclosed [sic] [enclosed] which is said to embody an oral order that the defendant had that day given the plaintiffs. The object of this letter was to have the terms of the oral agreement reduced to writing so that there could be no uncertainty as to the terms of the contract. The letter of the defendant of April 6th did not accept this offer. If the intention of the defendant had been to accept the offer made in the plaintiffs’ letter of April 4th, it would have been a simple matter for the defendant to have indorsed its acceptance upon the proposed contract which the plaintiffs’ letter of April 4th had inclosed. Instead of adopting this simple and obvious method of indicating an intent to accept the contract proposed by the plaintiffs the defendant submitted its own proposal and specified the terms and conditions upon which it should be accepted. The defendant’s letter of April 6th was not an acceptance of this offer made by the plaintiffs in their letter of April 4th. It was a counter-offer or proposition for a contract. Its provisions make it perfectly clear that the defendant (1) asked the plaintiffs to deliver rubber of a certain quality and quantity at the price specified in designated shipments; (2) it specified that the order therein given was conditional upon the receipt of its order being promptly acknowledged, and (3) upon the further condition that the plaintiffs would guarantee delivery within the time specified.