Thus far M. Say, but in his account of value and riches he has confounded two things which ought always to be kept separate, and which are called by Adam Smith, value in use and value in exchange. If by an improved machine I can, with the same quantity of labour, make two pair of stockings instead of one, I in no way impair the _utility_ of one pair of stockings, though I diminish their value. If then I had precisely the same quantity of coats, shoes, stockings, and all other things, as before, I should have precisely the same quantity of useful objects, and should therefore be equally rich, if utility were the measure of riches; but I should have a less amount of value, for my stockings would be of only half their former value. Utility then is not the measure of exchangeable value. If we ask M. Say in what riches consist, he tells us in the possession of objects having value. If we then ask him what he means by value, he tells us that things are valuable in proportion as they possess utility. If again we ask him to explain to us by what means we are to judge of the utility of objects, he answers, by their value. Thus then the measure of value is utility, and the measure of utility is value. M. Say, in speaking of the excellences and imperfections of the great work of Adam Smith, imputes to him, as an error, that "he attributes to the labour of man alone the power of producing value. A more correct analysis shews us that value is owing to the action of labour, or rather the industry of man, combined with the action of those agents which nature supplies, and with that of capital. His ignorance of this principle prevented him from establishing the true theory of the influence of machinery in the production of riches." In contradiction to the opinion of Adam Smith, M. Say, in the fourth chapter, speaks of the value which is given to commodities by natural agents, such as the sun, the air, the pressure of the atmosphere &c., which are sometimes substituted for the labour of man, and sometimes concur with him in producing.[29] But these natural agents, though they add greatly to _value in use_, never add exchangeable value, of which M. Say is speaking, to a commodity: as soon as by the aid of machinery, or by the knowledge of natural philosophy, you oblige natural agents to do the work which was before done by man, the exchangeable value of such work falls accordingly. If ten men turned a corn mill, and it be discovered that by the assistance of wind, or of water, the labour of these ten men may be spared, the flour, which is the produce of the work performed by the mill, would immediately fall in value, in proportion to the quantity of labour saved; and the society would be richer by the commodities which the labour of the ten men could produce, the funds destined for their maintenance being in no degree impaired.