有个问题，翻看《资本论》第一章，很多举例商品交换时，比如49页的两自然段：
    “某种一定量的商品，例如一夸特小麦，同x量鞋油或y量绸缎或z量金等等交换，总之，按各种极不相同的比例同别的商品交换。...”
    “我们再拿两种商品例如小麦和铁来说。不管二者的交换比例怎样，总是可以用一个等式来表示：一定量的小麦等于若干量的铁，如1夸特小麦=a吨(这里原是一个英制单位，打印不出来，故用“吨”代替，以下同。)铁。...”
  A given commodity, e.g., a quarter of wheat is exchanged for x blacking, y silk, or z gold, &c. — in short, for other commodities in the most different proportions. Instead of one exchange-value, the wheat has, therefore, a great many. But since x blacking, y silk, or z gold &c., each represents the exchange-value of one quarter of wheat, x blacking, y silk, z gold, &c., must, as exchange-values, be replaceable by each other, or equal to each other. Therefore, first: the valid exchange-values of a given commodity express something equal; secondly, exchange-value, generally, is only the mode of expression, the phenomenal form, of something contained in it, yet distinguishable from it.

  Let us take two commodities, e.g., corn and iron. The proportions in which they are exchangeable,whatever those proportions may be, can always be represented by an equation in which a given quantity of corn is equated to some quantity of iron: e.g., 1 quarter corn = x cwt. iron. What does this equation tell us? It tells us that in two different things — in 1 quarter of corn and x cwt. of iron, there exists in equal quantities something common to both. The two things must therefore be equal to a third, which in itself is neither the one nor the other. Each of them, so far as it is exchange-value, must therefore be reducible to
this third.
   
       请问，这些商品之间最早的交换比例，是用劳动价值论确定的，还是由市场自由讨价还价来确定的？