4. (1) A contract of sale of goods is a contract whereby the seller transfers or agrees to transfer the property in goods to the buyer for a price. There may be a contract of sale between one part-owner and another.(2) A contract of sale may be absolute or conditional.(3) Where under a contract of sale the property in the goods is transferred from the seller to the buyer, the contract is called a sale, but where the transfer of the property in the goods is to take place at a future time or subject to some condition thereafter to be fulfilled, the contract is called an agreement to sell.(4) An agreement to sell becomes a sale when the time elapses or the conditions are fulfilled subject to which the property in the goods is to be transferred.