2. We will next examine the inmost nature and the outward manifestations of _Value_. "Value" is by much the most important word in the Science of Economics; and we must, therefore, comprehend it thoroughly, root and branch. Nearly all the writers in English have used in place of this the word "Wealth" and those in other languages some equivalent and equally concrete word; but the present writer fully satisfied himself some twenty-five years ago, that it is impossible to use that word to any advantage in economical discussions, owing to its inherent ambiguities and concrete associations in the minds of men. He utterly discarded the word at that time, and has found not the least occasion to pick it up again since, and believes now that his substitution of the word "Value" in place of it will ultimately be seen to have been his greatest contribution to that Science, to which he devoted his life. Even professed and excellent logicians, like John Stuart Mill, found the word "Wealth" an insoluble element in the science of Economics; he commenced his great work by writing, that it was not really needful to _define_ the word which nevertheless he laid at the foundation of his discussions, that "every one has a notion sufficiently correct for common purposes of what is meant by Wealth"; he goes on, however, to give at least a half-dozen definitions of the word, no two of which are at all consistent with each other, only one of which embodies a clear and scientific conception, and even to this one he himself does by no means coherently adhere throughout his treatise. No wonder, that this great man died thoroughly dissatisfied with his own work in Economics, and wishing for longer life in which to recast and improve it! No wonder, too, that the crowd of writers both English and American, many of them able and thoughtful and otherwise logical, who have been content to continue to use this irreducible and utterly unscientific word at the bottom, have made a mess of it! In dropping the word, "Wealth," accordingly, Political Economy has dropped a clog, and its movements are now relatively free and certain; and it is all the more incumbent on the Science for that very reason to define the good word that it substitutes for a bad one with absolute clearness, to explain it through and through until it become quite transparent, and then always to use it in its defined and economical sense, and none other, even though the same word be properly enough used in other senses in common speech and in other than scientific relations. Exactly that is what we are now going to attempt to do in a simple and consecutive order.