Labour, I said, is a kind of exertion on the part of the individual, which begins and ends with each separate task it is employed upon; whilst Ability is a kind of exertion on the part of the individual which is capable of affecting simultaneously the labour of an indefinite number of individuals. ◆¹ Here are some examples. An English navvy, it is said, will do more work in a day than a French navvy; he will dig or wheel away more barrow-loads of earth; but the greater power of the one, if the two work together, has no tendency to communicate itself to the other. The one, let us say, will wheel twelve barrow-loads, whilst the other will wheel ten. We will imagine, then, a gang of ten French navvies, who in a given time wheel a hundred barrow-loads. One of them dies, and his place is taken by an Englishman. The Englishman wheels twelve loads instead of ten; but the rest of the gang continue to wheel ten only. Let us suppose, however, that the Englishman, instead of being a navvy, is a little cripple who has this kind of ability—that he can show the navvies how to attack with their picks each separate ton of earth in the most efficacious way, and how to run their barrows along the easiest tracks or gradients. He might quite conceivably enable the nine Frenchmen to wheel fifteen barrow-loads in the time that they formerly consumed in wheeling ten; and thus, though the gang contained one labourer less than formerly, yet owing to the presence of one man of ability, the efficacy of its exertions would be increased by fifty per cent. Or again, let us take the case of some machine, whose efficiency is in proportion to the niceness with which certain of its parts are finished. The skilled workman whose labour finishes such parts contributes by doing so to the efficiency of that one machine only; he does nothing to influence the labour of any other workman, or facilitate the production of any other machine similar to it. But the man who, by his inventive ability, makes the machine simpler, or introduces into it some new principle, so that, without requiring so much or such skilled labour to construct it, it will, when constructed, be twice as efficient as before, may, by his ability, affect individual machines without number, and increase the efficiency of the labour of many millions of workmen. Such a case as this is specially worth considering, because it exposes an error to which I shall again refer hereafter—the error often made by economic writers, of treating Ability as a species of Skilled Labour. For Skilled Labour is itself so far from being the same thing as Ability, that it is in some respects more distinct from it than Labour of more common kinds; for the secret of it is less capable of being communicated to other labourers. For instance, one of the most perfect chronometers ever made—namely, that invented by Mudge in the last century—required for its construction Labour of such unusual nicety, that though two specimens, made under