The cause which limits speculation in commodities, the tendency of increasing price to draw forth additional supplies, cannot limit the speculative advance in land values, as land is a fixed quantity, which human agency can neither increase nor diminish; but there is nevertheless a limit to the price of land, in the minimum required by labor and capital as the condition of engaging in production. If it were possible continuously to reduce wages until zero were reached, it would be possible continuously to increase rent until it swallowed up the whole produce. But as wages cannot be permanently reduced below the point at which laborers will consent to work and reproduce, nor interest below the point at which capital will be devoted to production, there is a limit which restrains the speculative advance of rent. Hence speculation cannot have the same scope to advance rent in countries where wages and interest are already near the minimum, as in countries where they are considerably above it. Yet that there is in all progressive countries a constant tendency in the speculative advance of rent to overpass the limit where production would cease, is, I think, shown by recurring seasons of industrial paralysis—a matter which will be more fully examined in the next book. BOOK V. THE PROBLEM SOLVED. CHAPTER I.—THE PRIMARY CAUSE OF RECURRING PAROXYSMS OF INDUSTRIAL DEPRESSION. CHAPTER II.—THE PERSISTENCE OF POVERTY AMID ADVANCING WEALTH. To whomsoever the soil at any time belongs, to him belong the fruits of it. White parasols, and elephants mad with pride are the flowers of a grant of land.—_Sir Wm. Jones’ translation of an Indian grant of land, found at Tanna._ * * * * * The widow is gathering nettles for her children’s dinner; a perfumed seigneur, delicately lounging in the Œil de Bœuf, hath an alchemy whereby he will extract from her the third nettle, and call it rent.—_Carlyle._ CHAPTER I. THE PRIMARY CAUSE OF RECURRING PAROXYSMS OF INDUSTRIAL DEPRESSION. Our long inquiry is ended. We may now marshal the results. To begin with the industrial depressions, to account for which so many contradictory and self-contradictory theories are broached. A consideration of the manner in which the speculative advance in land values cuts down the earnings of labor and capital and checks production leads, I think, irresistibly to the conclusion that this is the main cause of those periodical industrial depressions to which every civilized country, and all civilized countries together, seem increasingly liable.