learned Judges who heard the :tppmd held, disagreeing with the Trial Judge, that the good8 remained the sellers' property tiU the goods had been brought on board the ship and so the sales were exempted from tax under Art. 286(l)(b) of the Constitution. They however agreed with the Trial Judge that the sellers were liable 'to pay purchase tax under s. lO(b) of the Bombay Sales Tax Act. Accordingly they directed the Sales Tax Officer not to enforce the demand for payment of sales tax with regard to the sales of cotton for Rs. 68,493-2-6. and sale of castor oil of the total value of Rs. 6,47,509-1-6. The Sales Tax Officer has, on the strength of special leave granted by this Court, preferred the appeal which has been nnmbe.red as Civil Appeal No. 45 of 1959 o,gainst the appellate court's order directing him not to realise the sales tax in respect of sales of cotton and castor oil. Civil Appeal No. 46 of 1959 has been preferred by the sellers against the appellate court's judgment in so far as it upheld the as.sessment of purchase tax under s. lO(b). The only question for our decision in the a.ppeal by the Sales Tax Officer is whether property in the goods passed on shipment or· at some point of time before shipmAnt. The law is now well-s~ttled that if the property in the goods passes to the huyer after they have for the purpose of export to a foreign country crossed the customs frontier the sale has taken place "in course of the export" out of the territory of India. If therefore· in the present sales the property in the goods passed to the buyers on shipment, that is, after they had crossed the customs frontier the sales must be held to have taken place "in the course of export" and the exemption under Art. '286(l)(b) will come into operation. The sellers' case is that these were sales on .FOB contracts. Though the learned SolicitorGeneral appearing on bei1alf of the Sales Tax Officer tried to convince us that these were not really FOB contract sales, it appears that the avermeut in Paras. 11 and 13 of the writ petition that these sales were made on FOB basis were not denied in the counter affidavit sworn by the Sales Tax Officer. It is also