THEORY OF INTERNATIONAL VALUES
637
more (or not less) of a product (subject to the law of decreasing
returns) will continually be offered. For a converse reason our
curve may curl round like the dotted line in the figure. In short,
the varieties of curve marked as (3) and (4) in the fourth figure of
our Mathematical Part,1 do not occur in their scheme. Accord-
ingly they are not conducted to a certain proposition which we
have typified by the statement that, if Europe had an urgent
demand for the produce of the United States, it might be for the
interest of the United States to put an import tax on the produce
of Europe. Now as long as we consider the supply curve for
European articles as of the form O E, an import tax thereon can-
not come to much, as the authors observe (Theorie des Preises,
p. 417). The curling round of the curve is required to express
the urgency of the European demand for American produce.
While we consider the supply curves of particular articles of
the form O E, we do not get beyond the effect which we have
likened to the buffer of a railway carriage being pushed back ;2 to
contemplate the movement imparted to the whole train, we
1 Ante, p. 480.
2 Ante, p. 46.
U U
No. 16.—VOL. IV