Concept Of A Sale By Description
In ordinary sense s.13 of the Sale of Goods Act (SGA) 1979 says that where there is contract for goods by description, there is an implied condition that the good must correspond with the description.  However, the description may come from the seller or the buyer.  Furthermore, s.13 also applies (unlike s.14) even though the goods are not sold ‘in the course of a business’ by the seller, Varley v Whipp.  Before discussion about s.13 of SGA 1979, we should make clear the implied terms. Moreover, for s.13 the first question to be examined the distinction between mere representation on the one hand and terms of the contract on the other hand. 
Under the SGA 1979 the implied terms are ‘conditions’ or ‘warranties’. For breach of a condition the innocent party has right to repudiate the contract as well as claiming the damages and for breach of warranty they has the only right to damages. 
Sale by Description:
“Before going to the discussion two principle questions should be asked. First, when does a sale of goods agreement take place by description, and secondly, which words used constitute that description?"  The words of s.13(1) cannot answer either question, but s.13(3) can give some assistance to the first question which states that exposing goods for sale or hire does not prevent a sale of goods from being a sale by description. S.13(2) makes clear the second question, which says that in case of sale by sample, compliance of the goods with the sample does not require to comply also with the description. 
In T & J Harrison v Knowles and Foster  , no reference was made about the capacity of the ships in the actual memorandum of sale. In fact, the capacity of each ship was only 360 tons where it was described as 460 tons at the time of contract. But the Court of Appeal held that the statements were merely representation. In Harlingdon & Leinster Ltd v Christopher Hull Fine Art Ltd  it was held that the sale was not by description, because the description was not influential to become an essential term or condition of the contract and there was no reliance on part of the buyer. However, Beale v Taylor  reflect the modern trend that statements about the goods made by the seller are to be treated as contractual terms rather than mere representation, particularly where there was a reasonable reliance on the statement on part of the buyer. Where descriptive words fail to comply with s.13 may simply be a misrepresentation and the remedies would be available for a misrepresentation for the representee. 
Where the contract is for unascertained goods, it is beyond controversy that the sale must be by description since the buyer must have some assumption that the goods supplied by the seller is the contracted goods.  But in some cases it becomes difficult for the range of the description, particularly the difference between words that identify goods and that denote the quality of goods.  In Varley v Whipp  , the defendant agreed to buy a reaping machine from the claimant, which was unseen and which was described as had been new the previous year and hardly used at all. This was a gross misdescription and the defendant declined to accept it or pay for it after delivery. 
Before Varley v Whipp the difficulties arose to make a clear distinction between the specific and unascertained goods. At that time, a number of unascertained goods were required to deliver that conformed to the identity as opposed to any collateral attributes that might have been represented at the time of contract. Thus goods failed to conform the contractual description in Azemar v Casella  ‘Western Madras’ cotton, an inferior type, instead of the ‘Long-staple Salem’ cotton; likewise in Bridge v Wain  the goods were ‘scarlet cuttings’ with an adulterative addition of serge which did not conform to the market understanding of ‘scarlet cuttings’. In these cases the liability of the seller was for the breach of warranty. For the sale of unascertained future goods, each details of the description must be assumed to be vital  (keeping in mind Arcos v E A Ronaseen  ) and non-conformity with the contractual goods is sufficiently serious for a breach of implied condition (Chanter v Hopkins  ). Even in Josling v Kingsford  specific goods examined before the contract, the obligation for description could still be infringed where the examination could not properly revealed a latent misdescription, as where the substantial admixture of Epsom salts could not be detected the quantity of oxalic acid by the naked eye. A very strict approach was taken in Bowes v Shand  where it was invoked to timely shipment of an agreed quantity of unascertained goods.
In modern law, the age of goods consider to be their identity. Thus in Nicholson and Venn v Smith-Marriott  , the authenticity of tablecloths and napkins as formerly owned by Charles I went to description in s.13. For unascertained goods in modern times, the leading case is Arcos Ltd v EA Ronaasen and Son  , where the buyer rejected the wood for not to comply with precise measurement of length, breadth and thickness, though not injurious for the purpose of the buyer in making staves of cement barrels. The Supreme Court (formerly House of Lords) made it clear that, physical measurement was a matter of description (Ebrahim Dawood Ltd v Health Ltd  2 Lloyd’s Rep. 512) and compliance with description meant exact and not approximate compliance. So it was entitled the breach of s.13(1).  But in Ashington Piggeries Ltd v Cristopher Hill Ltd  the range of description for unascertained goods was clearly cut down.
Hence s.13 also applies where the buyer has seen the goods as seen in Grant v Australian Knitting Mills Ltd  (1936) where Lord Wright said:
“It may also be pointed out that there is a sale by description even though the buyer is buying something displayed before him on the counter: a thing is sold by description, though it is specific, so long as it is sold not merely as the specific thing, but as a thing corresponding to a description, e.g. woollen undergarments, a hot-water bottle, a second hand reaping machine, to select a few obvious illustration." 
Moreover, it has been made clear by s.13(3) that where the goods have been exposed for sale and selected by the buyer, as in supermarket or department store, all are covered by the term ‘sale by description’. Even prior to the Supply of Goods (Implied Terms) Act 1973 amendments it had been held that a sale could be by description though the buyer had examined the goods with care (Beale v Taylor  ) or even where he had selected the goods from the stock offered by the seller (H Beecham & Co Pty Ltd v Francis Howard & Co Pty Ltd  ). “But a sale is not by description where the buyer makes it clear that he is buying a particular thing because of its unique qualities and that no other will do, or where there is absolutely no reliance by the buyer on the description (Harlingdon & Leinster Ltd v Christopher Hull Fine Art Ltd  1 QB 564)". 
For this reason almost always the sale of a manufactured item will be a sale by description (except where it is second-hand) because articles made to an identical design are not bought as unique goods rather it is good corresponding to that design. Even in a Australian case in David Jones Ltd v Willis  it was held that, “the sale of an ordinary pair of ‘walking shoes’ was a sale by description, although the buyer had tried on and examined the shoes and might well have been thought to be buying the particular pair as specific goods". Even in Beale v Taylor  though the purchase of a second-hand car was fully examined by the buyer but it was held to be a sale by description because the buyer had relied on the newspaper advertisement issued by the seller. But if the buyer may examine a second-hand car and the seller may offer by saying: ‘There is a car; there is my offer; I guarantee nothing; take it or leave it’, would be held to be a sale of a specific thing and not a sale by description. 
One of the consequences of the Sale of Goods Act 1893 that the practice of courts were tended to interpret s.13 with the half an eye to s.14, because if the sale was a sale by description there would often be an implied condition that the goods were merchantable under s.14. As we have seen in Arcos Ltd v E A Ronaasen & Son  , though it is quite possible for a good to be satisfactory (formerly merchantable) quality and fit for purpose, yet not correspond with description.  Conversely, if the correspond with description though not satisfactory or fit for purpose will not be enable to plea a breach of s.13. However, first, s.13 is applicable to private seller while s.14 is only applicable who sells in the course of a business. Secondly, where the goods are in fact of satisfactory quality in a general sense, but still not the goods that the buyer thought he was buying, then the buyer may rely on s.13. Thirdly, where the contract contains an exclusion clause from the liability for the matters of quality, but not for the matters of description, the buyer may wish to rely upon s.13. 
“It is slightly odd that s.13 says nothing about the possibility that the buyer may examine the goods and come to realize that the description is not entirely accurate or perhaps that he should have realized this."  It would be very odd to hold the liability of the seller for breach of s.13 in such cases and it is expected that the courts would avoid such a result by holding that the sale is not by description.