From 1803, a period of almost fifty years, since Ricardo published his doctrine of Rent, there has not been even an attempt, except Carey's, to add any thing to political economy. Senior, Whateley, and a thousand others, have been disputing about words, while as many others have been attacking Malthus and Ricardo; but no one has attempted to discover laws, to take the place of those which were assailed. Of the supporters of these writers, every one has been compelled to admit that their laws did not cover the facts, and to interpolate accommodating passages. John Stuart Mill, in his recent work, has done this even more largely than his predecessors, and so furnished additional proof that their laws were _not_ laws, but mere anarchy. Ricardo had to leave a place of escape for difficult facts[24] and his successors have since found themselves obliged to open so many new ones, that his laws are now like sieves. The period was propitious for a discoverer. The opinion of D'Alembert that the steps of Civilization were to be taken in the middle of each century, was to be confirmed by a new illustration. Mr. Carey's father was a practical man; all his children were trained to affairs; thus they became observers. The students of books are rarely creators in science. Truth is most likely to be evolved in the school of experience. From the age of seven years until he was twenty-one, Mr. Carey was in his father's bookstore. From 1821 to 1838, he was a partner in the important publishing house of Carey, Lea & Carey, and Carey & Lea; but in this period he passed one season abroad, we believe immediately after his marriage with a sister of Leslie the painter. The determination of his mind was already fixed, when his retirement from business enabled him to devote his faculties entirely to the science with which his name will for ever be associated. Mr. Carey's first book--_An Essay on the Rate of Wages_--was published in 1836, and was soon after expanded into _The Principles of Political Economy_, which appeared in three octavo volumes in 1837--1840.