IN NATURE of July 4 Prof. Louis criticises my paper, “Germany's Natural Wealth,” which appeared in the Fortnightly Review of June. In that paper I pointed out that the wealth of Germany in coal, iron-ore, and potash amounts to at least 240,000,000,000l., taking the value of coal and of potash at 10s. per ton and that of iron-ore at 5s. per ton. Prof. Louis, on the other hand, tries to show that the value of Germany's three principal minerals comes only to 700,000,000l., and asserts that I have overstated Germany's mineral wealth more than three hundred times.