Excerpt from Coal in International Trade This little book is not a scientific treatise; its purpose is to provide matter for thought, to suggest problems rather than solutions. It is an attempt to place side by side certain groups of facts which are intimately related but not easy to study in their widely scattered sources. The method involves the comparison of things not strictly comparable and the use of figures subject to large initial errors in addition to the errors inevitable in handling and reproduction. A rigid statistician may take refuge in economic agnosticism; he may argue that nothing of real value can result from material so imperfect; such material, however, is sometimes better than none. The world will not await ideal statistics either for argument or for action; and where evidence is cumulative, a very considerable correction for error may leave the essentials of the picture untouched. In the sphere of commerce, even an approximate estimate of the factors...