And in general, while the slightest examination of what is passing around us must convince us that commodities, under deduction of rent and taxes, _do not_ ordinarily exchange with each according to the quantity of human labour worked up in them, the same examination will convince us that, under the same deduction, they do ordinarily exchange with each other, according to the quantity of human labour _and of profits_ worked up in them; and further, that the quantity of human labour worked up in them, with the profits upon the advances for the time that they have been advanced, is correctly measured by the quantity of human labour of the same kind which the commodity so composed will ordinarily command. We must carefully, therefore, distinguish between _measuring_ profits by labour, and meaning profits by labour; and while the first is obviously justifiable, and may be in the highest degree useful, it must be allowed, that the latter contradicts all the most obvious rules for the use of terms: it contradicts the usage of common conversation: it contradicts the highest authorities in the science of political economy: it embarrasses all explanations; and it cannot be maintained with consistency. Though Mr. Macculloch’s work affords other instances of a want of attention, on a point so important in all philosophical discussions, as appropriate and consistent definitions, I will only notice further, his use of the term _real_. He applies it to wages, in two senses entirely different. In part iii. p. 294, he says, “But if the variation in the rate of wages be _real_, and not nominal, that is, if the labourer be getting either a greater or less _proportion of the produce of his industry_, or a greater or less quantity of money of invariable value, this will not happen.” Here, it is evident that Mr. Macculloch applies the term _real_ to wages, in the sense of proportional wages, that is, as Mr. Ricardo applied it. In part iii. p. 365, Mr. Macculloch says, “If the productiveness of industry were to diminish, proportional wages might rise, notwithstanding that _real wages_, or the _absolute amount of the produce_ of industry falling to the share of the labourer, might be diminished. Here, the term real wages is used as synonymous with the absolute amount of produce falling to the share of the labourer, that is, in the sense in which Adam Smith has applied it.” I have already observed, that Adam Smith’s application of the term _real wages_, to the absolute quantity of the produce earned by the labourer, seems to be a most natural one; and Mr. Ricardo’s application of the same term to the _proportion_ of the produce earned by the labourer, a most unnatural one. Mr. Macculloch, therefore, was quite right, in introducing the term _proportionate wages_, to express Mr. Ricardo’s meaning; but why not adhere to it? Why should he, in some places, mean, by real wages, proportionate wages, and, in other places, something totally different?