INTERNATIONAL TRADE 
CHAPTER 1 
THREE CASES 
Ar the outset I must ask the reader’s patience, and a with- 
holding of judgment on his part, till the close of a systematic and 
prolonged exposition. Some assumptions will be made in the 
earlier chapters that must appear quite out of accord with facts, 
and some extremely simple and apparently unreal situations will be 
considered. It will be assumed, for example, that countries or 
regions trade with each other by a process of barter, and that the 
people concerned weigh deliberately the advantages of barter. It 
will be assumed, again, that within each country commodities are 
exchanged, by those making them, on the basis of the quantities 
of labor given to their production. These commodities, too, will 
be assumed to be produced at constant cost — that is, tho the vol- 
ume of output may change, each unit is always produced by the 
same quantity of labor. And so on thru a long list of provi- 
sional suppositions. As the subject is unfolded step by step, these 
will be qualified and supplemented, and verisimilitude will be 
attained, or at least some approach to verisimilitude. Many 
comments and criticisms that must arise in the reader’s mind will 
be met, I trust, as he proceeds. He is asked to judge the analysis 
which follows as a whole, regardless of seeming inadequacy in any 
one part considered by itself. 
We begin by distinguishing three sorts of cases. To these may 
be applied the terms: (1) absolute differences in cost; (2) equal 
differences in cost; (3) comparative differences in cost. 
In the analysis and interpretation of these cases, “cost” will 
mean labor cost, measured in terms of time, — so many days. A