PREFACE 
It is the simpler and more fundamental aspects of the theory which 
have been chiefly dealt with. Some refinements that bulk large in the 
literature of the subject have been disregarded. I have directed 
attention to the leading principles, and with a view to their practical 
significance rather than their theoretical nicety. More especially, 
those have been developed for which there seemed to be a possibility 
of applying the processes of test and verification undertaken in the 
second Part. Some intricate and much discussed elaborations of 
theory, especially on the play of demand and on the effects of import 
and export taxes, have been almost entirely ignored. 
To the conversant reader an explanation is due, and perhaps an 
apology, for the simplicity of Part I and for the way in which the 
illustrative figures are used. The procedure followed can hardly be 
dignified by calling it mathematical, since only the simplest operations 
in arithmetic are carried on. My inability to use the methods of 
higher mathematics prevents me from following beyond the initial 
stages the elaborated treatment which has been applied to the subject 
by a long succession of 19th century writers. The excuse which I 
would offer for handling the problems in ways that must seem ele- 
mentary to the mathematical economists is two-fold. First, with the 
tools at my command I have tried to grapple with parts of the subject 
at large which do not seem to have received attention from those 
better equipped; and thereby perhaps something has been added to 
the theoretic framework. And second, I have some hope that the very 
simplicity of the computations and illustrations of this book will 
contribute to their practical significance. In order to come as close as 
possible to actuality, the theoretic conclusions have here been worked 
out in terms of prices and money incomes. By thus pushing them 
to the stage of concreteness and verisimilitude, they have been made 
more amenable to test, verification, correction. 
In Part II, which takes up these processes of verification, I have 
departed farther from the beaten track. The pure theory of inter- 
national trade constitutes only the initial stage toward the ascertain- 
ment of the things we wish in the end to know. Such indeed is the 
case with the whole of the pure theory of economics, which can be 
called “the” theory rather than “a” theory, solely on the ground that 
no other has been put forward which is generalized, consistent, intel- 
lectually satisfactory. After all, what we wish to attain is not a 
neat logical structure, but an understanding of the actualities. We