◆¹ Perhaps then it will be said that they are due to differences of soil and climate. But again, that will not explain the differences, at various dates, between the incomes of the same countries; and though it may explain a little, it will not explain much, of the differences at the same date between the incomes of different countries. The soil and climate, for instance, of the United Kingdom, are not in themselves more suited for agriculture than the soil and climate of France and Belgium; and yet for each individual actually engaged in agriculture, this country produces in value twenty-five per cent more than France, and forty per cent more than Belgium. I may add that it produces forty-six per cent more than Germany, sixty-six per cent more than Austria, and sixty per cent more than Italy.[21] [Sidenote ◆1 Nor of hours of labour,] ◆¹ Perhaps then a third explanation will be suggested. These differences will be said to be due to differences in the hours of labour. But a moment’s consideration will show that that has nothing to do with the problem; for when a million people in this country produced half what they produce to-day, they had fewer holidays, and they worked longer hours. Now that they have doubled the annual produce, they take practically four weeks less in producing it.[22] Again, the hours of labour for the manufacturing classes are in Switzerland twenty-six per cent longer at the present time than in this country; and yet the annual product, in proportion to the number of operatives, is twenty-eight per cent less.[23] Agriculture gives us examples of the same discrepancy between the labour expended and the value of the result obtained. In France, the agricultural population is three times what it is in this country, but the value of the agricultural produce is not so much as double.[24] [Sidenote ◆1 But are causes of some other kind which lie below the surface,] Plainly, therefore, the growth of a nation’s income, under modern conditions, does not depend on an increased expenditure of labour. There might, indeed, seem some ground for leaping to the contrary conclusion—that it grows in proportion as the hours of labour are limited: but whatever incidental truth there may be in that contention, it does not explain the main facts we are dealing with; for some of the most rapid changes in the incomes of nations we find have occurred during periods when the hours of labour remained unaltered; and we find at the present moment that countries in which the hours of labour are the same, differ even more, in point of income, from one another than they differ from countries in which the hours of labour are different. ◆¹ Whatever, therefore, the causes of such differences may be, they are not simple and superficial causes like these. [Sidenote ◆1 And which requires to be carefully searched for.]