P entered into a written contract with D for the sale of thirty tons of casein. The contract contained a clause: 'Shipment: May-June from Europe. Advice of shipment to be made by cable immediately goods are dispatched.' Fifteen tons of casein were shipped on June 9th, 1923. No notice of shipment was given to D. Tender of this shipment P was refused by D on June 20th. On June 21st D wrote to P that P 'failed to make any May delivery under the contract and also failed to advise us of shipment as required to do by your contract.' P declined an offer of D 'to take this shipment as the June quota on your contract and call the contract filled.' On June 26th P shipped the remaining fifteen tons of casein. D received no advice of shipment 'by cable' immediately after the goods were shipped. It did receive a letter from P dated June 23d, that P had received advice by cable that these fifteen tons would be shipped per steamship Magnolia sailing on June 26th, and another letter from P on June 28th stating that upon the arrival of the steamship Magnolia 'which sailed on June 26th with the balance of your order on board, we will deliver to you the full 30 tons of Casein in conformity with our contract.' On the arrival of the steamship, Magnolia P tendered to D the thirty tons of casein. D refused the tender.