_protecting_ duty, or other preference given to domestic
over foreign industry. But in regard to those duties on foreign
commodities which do not operate as protection, but are maintained
solely for revenue, and which do not touch either the necessaries of
life or the materials and instruments of production, it is his opinion
that any relaxation of such duties, beyond what may be required by the
interest of the revenue itself, should in general be made contingent
upon the adoption of some corresponding degree of freedom of trade with
this country, by the nation from which the commodities are imported.

CONTENTS.

ESSAY I.

Of the Laws of Interchange between Nations; and the Distribution of the
Gains of Commerce among the Countries of the Commercial World

ESSAY II.

Of the Influence of Consumption upon Production

ESSAY III.

On the Words Productive and Unproductive

ESSAY IV.

On Profits, and Interest

ESSAY V.

On the Definition of Political Economy; and on the Method of
Investigation proper to it

ESSAY I.

OF THE LAWS OF INTERCHANGE BETWEEN NATIONS; AND THE DISTRIBUTION OF THE
GAINS OF COMMERCE AMONG THE COUNTRIES OF THE COMMERCIAL WORLD.

Of the truths with which political economy has been enriched by Mr.
Ricardo, none has contributed more to give to that branch of knowledge
the comparatively precise and scientific character which it at present
bears, than the more accurate analysis which he performed of the nature
of the advantage which nations derive from a mutual interchange of their
productions. Previously to his time, the benefits of foreign trade were
deemed, even by the most philosophical enquirers, to consist in
affording a vent for surplus produce, or in enabling a portion of the
national capital to replace itself with a profit. The futility of the
theory implied in these and similar phrases, was an obvious consequence
from the speculations of writers even anterior to Mr. Ricardo. But it
was he who first, in the chapter on Foreign Trade, of his immortal
_Principles of Political Economy and Taxation_, substituted for the
former vague and unscientific, if not positively false, conceptions with
regard to the advantage of trade, a philosophical exposition which
explains, with strict precision, the nature of that advantage, and
affords an accurate measure of its amount.

He shewed, that the advantage of an interchange of commodities between
nations consists simply and solely