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so that an addition to the one renders a part of the other, or others,

Moreover, this is exactly the same condition as in the preceding case and can, especially if we restrict our observations to two commodities only, be represented by exactly the same diagram as before, in which, by the horizontal line AB (see Fig. 1), we now represent the quantity of goods in hand at the beginning-or, what amounts to the same thing, their exchange value (e.g. in money)—whilst the marginal utility of the goods, partly for direct consumption and partly in the “ converted ” form assumed by exchange-or the utility of the last shilling’s worth of each commodity-is represented by the ordinates of the two curves.