In August, The Cooper Manufacturing Co. contracted with Millard Oil Company for the delivery of 75,000 gallons of heating oil at the price of $ 2.20 per gallon at regularly specified intervals during the upcoming winter season. Due to an unseasonably warm winter, Cooper took delivery on only 65,000 gallons. When Millard sued Cooper for breach of contract, Cooper claimed that it was impossible to complete the contract because of the unseasonably warm weather. Is Cooper liable for breach of contract?