5. We must now study with considerable pains the ultimate facts and the essential functions of LANDS in connection with the Production of material commodities. This has always been the most vexed question in our Science; but it is approaching, even if it has not already reached, a satisfactory and final solution. The present writer believes that his own studies and researches have thrown some original and important light upon the perplexing problem of the Value of lands and of their produce. His present readers are surely entitled to his clearest possible presentation of all the facts and principles of this radical question. The French "physiocrats" of a hundred years ago, founders of the first School in Political Economy, excellent men for the most part as well as good economists in general, thought, that lands were property in a peculiar and eminent sense, that they were the ultimate source of all values but their own, and that consequently lands should bear the weight of the national taxes. English economists, constituting with their followers in other countries the second School in our Science, while not going to the length of the physiocrats, still maintained that the value of lands and of the produce of lands were distinct in important respects from all other values whatever. In our own time and country, Henry George, though belonging for the most part to the third economic School, is a great stickler for a single tax on lands in lieu of all other taxes. We must, then, concentrate all the lights we can gather on these points of dispute and difficulty. (a) _The presumption in science is always against the existence of a few outlying cases, whenever the induction has been long and carefully conducted by many persons, and the generalization appears on all other grounds to be sound and comprehensive._ All induction proceeds upon the premise, that Nature is _uniform_ in those essential resemblances that constitute a _class_ of things in science. Nature has so often justified confidence in her essential resemblances even under the greatest differences in external circumstance and apparent diversity, that the presumption becomes immensely strong in her favor, whenever a generalization patiently gathered from many particulars seems to cover the whole ground concerned except a few obstinate-looking items, that have not yet been closely studied. Two to one these items also will presently fall into their predestined place. We have already seen abundant grounds for believing, that Values arise from human services rendered and received: is it at all likely, considering the nature of scientific generalization and the history of all the more advanced sciences, that in Political Economy, lands and their produce should be found to constitute an outlying exception to the law of all other valuable things?