For present purposes, two species of unascertained goods may be distinguished.
2.
Unascertained goods may form the subject matter of a valid contract of sale.
3.
It is common ground that the contracts in question were for the sale of unascertained goods.
4.
While the situation envisaged in respect of unascertained goods is analogous to that above, the price is usually ascertained, but the " res vendita " is not.
5.
Where the " res vendita " comprises unascertained goods, the seller must appropriate them to the contract and ensure that the quantity and description and quality of the goods thus appropriated are in accordance with the terms of the contract.