Sec.5. Some paradoxical reactions of price changes on supply.  Let us turn, though, once more to these earlier laws, and with a heightened critical sense let us submit them to the test of the whole gamut of our experience, and see if in any of them we can find the smallest flaw.  The first of them will pass through the ordeal—­let each reader prove it for himself—­unscathed.  The second will emerge with a few hairs, as it were, singed.  It tells us, for instance, that a rise in price will tend to augment the supply.  Now there are some things the supply of which cannot possibly be augmented; these are the capital resources of nature, of which land is the most important for our present purpose.  Land is bought and sold, it commands a price.  In a certain sense, it may be said to be possible to increase the supply of land, in response to a rise in price, by drainage and reclamation schemes; and it will certainly happen that a rise in the price which land can command for any particular purpose will increase the amount which is devoted to that purpose.  But, speaking broadly, the supply of land available for purposes of every kind is a fixed unvarying factor, with an inertia which the cajolery of price-changes is powerless to disturb.  This is a most important fact, and it gives rise to some peculiar features of the price and rent of land, which we shall have to consider later as a separate problem.  It constitutes a limiting case rather than an exception to the general law.  But we have not yet done with the reactions of price upon supply.  In the case of capital, the nature of those reactions has been much discussed as a highly controversial question.  That a rise in the rate of interest will cause some people to save more than before, is generally admitted; but it is pointed out that the effect upon others may be the exact opposite, because it means that they do not need to save so much to acquire the same future annual income.  It is unwise to say dogmatically that the former tendency outweighs the latter; though upon the whole it seems highly probable that it does.  We cannot, therefore, in this case feel confident that a change in price will react upon supply in the manner which our law indicates.  Similarly it is possible to argue that a rise in the general level of real wages may reduce the supply of labor, even, or some might say particularly, if the term is used to denote not the number of workpeople, but the quantity of work done.  For there may be a tendency for workpeople, when more comfortably off, to work less regularly or less hard.  Here again we cannot be sure.  In none of these cases, however, including that of land, is there any reason to doubt that a rise in price will diminish demand, or conversely that a fall will increase it.  Since, therefore, in the reasoning by which we deduced the third law, the conclusion will hold good, even if the effects of price-changes on supply are of the above paradoxical kind, provided that they do not continually outweigh the effects upon demand, there is no reason to cast doubt on the solidity of Law III, which, indeed, as we suggested before, commends itself directly to experience.  But Law II seems now, perhaps, somewhat the worse for wear.