Now, in studying history, the difficulty is about the delicacy of the lock, and the mode of applying the key. We doubt not that many readers will view all this as false refinement. But hardly, if they had much considered the real experimental cases in history. For instance, suppose the condition of a people known as respects (1) civilization, as respects (2) relation to the sovereign, (3) the prevailing mode of its industry, (4) its special circumstances as to taxation, (5) its physical conformation and temperament, (6) its local circumstances as to neighbours warlike or not warlike, (7) the quality and depth of its religion, (8) the framework of its jurisprudence, (9) the machinery by which these laws are made to act, (10) the proportion of its towns to its rural labour, and the particular action of its police; these and many other items, elements, or secondary features of a people being known, it yet remains unknown which of these leads, which is inert, and of those which are not inert in what order they arrange their action. The _principium movendi_, the central force which organizes and assigns its place in the system to all the other forces, these are quite undetermined by any mere arithmetical recitation of the agencies concerned. Often these primary principles can be deduced only tentatively, or by a regress to the steps, historically speaking, through which they have arisen. Sometimes, for instance, the population, as to its principle of expansion, and as to its rate, together with the particular influence socially of the female sex, exercises the most prodigious influence on the fortunes of a nation, and its movement backwards or forwards. Sometimes again as in Greece (from the oriental seclusion of women) these causes limit their own action, until they become little more than names. In such a case it is essential that the leading outlines at least should be definite; that the coast line and the capes and bays should be well-marked and clear, whatever may become of the inland waters, and the separate heights in a continuous chain of mountains.