On the other hand, the discovery of the productive, value-creating property of every kind of labour, alike in agriculture and in manufacture, suggested to Smith that agricultural labour, too, must produce, apart from the rent for the landowning class, a surplus for the tenant class over and above the total of their capital expenses. Thus, in addition to the replacement of capital, an annual income of the tenant class comes into being.[70] Lastly, by a systematic elaboration of the concepts of _avances primitives_ and _avances annuelles_ introduced by Quesnay, which he calls fixed and circulating capital, Smith has made clear, among other things, that the manufacturing side of social production requires a fixed as well as a circulating capital. Thus he was well on the way to restoring to order the concepts of capital and revenue of society, and to describing them in precise terms. The following exposition represents the highest level of clarity which he achieved in this respect: 'Though the whole annual produce of the land and labour of every country is, no doubt, ultimately destined for supplying the consumption of its inhabitants and for procuring a revenue to them, yet when it first comes either from the ground or from the hands of the productive labourer, it naturally divides itself into two parts. One of them, and frequently the largest, is, in the first place, destined for replacing a capital, or for renewing the provisions, materials, and finished work, which had been withdrawn from a capital; the other for constituting a revenue either to the owner of this capital, as the profit of his stock, or to some other person, as the rent of his land.'[71] 'The gross revenue of all the inhabitants of a great country comprehends the whole annual produce of their land and labour; the neat revenue, what remains free to them after deducting the expense of maintaining, first, their fixed, and secondly, their circulating capital; or what, without encroaching upon their capital, they can place in their stock reserved for immediate consumption, or spend upon their subsistence, conveniencies, and amusements. Their real wealth too is in proportion, not to their gross, but to their neat revenue.'[72] The concepts of total capital and income appear here in a more comprehensive and stricter form than in the _Tableau Économique_. The one-sided connection of social income with agriculture is severed and social income becomes a broader concept; and a broader concept of capital in its two forms, fixed and circulating capital, is made the basis of social production as a whole. Instead of the misleading differentiation of production into two departments, agriculture and industry, other categories of real importance are here brought to the fore: the distinction between capital and income and the distinction, further, between fixed and circulating capital.