I have changed the titles “Ricardo’s Law of Rent,” and “The Malthusian Law of the Increase of Population,” which I formerly used, for others. But I would not be misunderstood here. I hold it to be a duty of reverence in the learned—as it has long been practiced in the case of the natural sciences—in the sciences of the human mind to call the natural laws, methods etc., in acquainting us with which, some one particular investigator has won very distinguished merit, by the name of that investigator. In the case of the law of rent, the application of this rule would as unquestionably entitle Ricardo to this honor as it would Malthus in that of the increase of population, spite of the fact that Ricardo may not have succeeded in finding the best possible form of the abstraction, and although Malthus even, in a one-sided reaction against a former still greater one-sidedness, was not always able to steer clear of positive and negative errors. Recent science has endeavored, and successfully, to examine the facts which contradict the Ricardoan and Malthusian formulations of the laws in question, and to extend the formulas accordingly. I have myself contributed hereto to the extent of my ability. But, in the interval, it is not hard to comprehend that, while this process of elucidation is going on, most scholars, those especially possessed more of a dogmatic than of a historical turn of mind, should estimate these two leaders more in accordance with their few defects than with the great merits of their discoveries. If, therefore, I now drop the title “Malthusian law,” it is to guard hasty readers from the illusion that §§ 242 seq. teach what the great crowd understand by Malthusianism; when they might, perhaps, omit that portion entirely. For my own part, I have no doubt that, when the process of elucidation above referred to shall have been thoroughly finished, the future will accord both to Ricardo and Malthus their full meed of honor as political economists and discoverers of the first rank.(1) PRELIMINARY ESSAY. Preliminary Essay On The Application Of The Historical Method To The Study Of Political Economy, By M. Wolowski, Member Of The Institute Of France. “_Nunquam bene percipiemus usu necessarium nisi et noverimus jus illud usu non necessarium. Nexum est et colligatum alterum alteri. Nulli sunt servi nobis, cur quæstiones de servis vexamus? Digna imperito vox._”—_Cuj._, vii, in titul. Dig. De Justitia et Jure.(2) “_Homo sum, humani nihil a me alienum puto._”—_Terence._(3) “_Ista præpotens, ac gloriosa philosophia._”—_Cicero_, De Or., I, 43.(4) I.