It seems clear that the practical liberation and distribution throughout the world of all good gifts meant for the whole household of man, has been confided to the secret sense of a _right_ existing in man for claiming such a distribution as part of his natural inheritance. Many articles of almost inestimable value to man, in relation to his physical well-being (at any rate bearing such a value when substitutional remedies were as yet unknown) such as mercury, Jesuit's bark, through a long period the sole remedy for intermitting fevers, opium, mineral waters, &c., were at one time _locally_ concentred. In such cases, it might often happen, that the medicinal relief to an hospital, to an encampment, to a nation, might depend entirely upon the right to _force_ a commercial intercourse. Now, on the other hand, having thus noticed the question, what commercial value has China irrevocably for England, next in the reverse question--namely, what commercial value does England bear to China?--I would wish to place this in a new light, by bringing it for the first time into relation to the doctrine of rent. Multitudes in past days, when political economy was a more favoured study, have spoken and written upon the modern doctrine of rent, without apparently perceiving how immediately it bears upon China, and how summarily it shatters an objection constantly made to the value of our annual dealing with that country. First, let me sketch, in the very briefest way, an outline of this modern doctrine. Two men, without communication, and almost simultaneously, in the year 1815, discovered the law of rent. Suddenly it struck them that all manufactured products of human industry must necessarily obey one law; whilst the products of land obey another and opposite law. Let us for a moment consider arable land as a natural machine for manufacturing bread. Now, in all manufactures depending upon machinery of human invention, the natural progress is from the worse machines to the better. No man lays aside a glove-making machine for a worse, but only for one that possesses the old powers at a less cost, or possesses greater powers, let us suppose, at an equal cost. But, in the natural progress of the bread-making machines, nature herself compels him to pursue the opposite course: he travels from the best machines to the worse. The best land is brought into cultivation first. As population expands, it becomes necessary to take up a second quality of land; then a third quality; and so on for ever. Left to the action of this one law, bread would be constantly growing dearer through a long succession of centuries. Its tendency lies in this direction even now; but this tendency is constantly met, thwarted, and retarded, by a counter-tendency in the general practice of agriculture, which is always slowly improving its own powers--that is, obtaining the same result at a cost slowly decreasing. It follows as a consequence, when closely