When presently the machine technology comes forward this habitual preconception touching the invariability of material quantity finds new applications and new refinements of application, with the outcome that its guidance of men’s thinking grows ever more inclusive and more peremptory. But it is not until half a century after the Industrial Revolution that the principle may be said finally to have gained unquestioning acceptance as a theorem universally binding on material phenomena. By that time--about the second quarter of the nineteenth century--the unqualified validity of this theorem had become so unmitigated a matter of course as to have fairly shifted from the ground of empirical generalisation to that of metaphysical thesis. Men of science then quite ingenuously set about proving the law of the Conservation of Energy by appeal to experiments and reasoning that proceeded with absolute naïveté on the tacit assumption of the theorem to be proven. * * * * * In its bearing on the growth of institutions the machine technology has yet scarcely had time to make its mark. Such institutional factors as, e. g., the common law are necessarily of slow growth. A system of civil rights is not only a balanced scheme of habitual responses to those stimuli at whose impact they take effect; it is at the same time a scheme which has the sanction of avowed common consent, such as will express itself in rating these institutional elements as facts of immemorial usage or as integrally inherent in the nature of things from the beginning. Such civil institutions take shape as prescriptive custom, and matters of habit which so are supported by broad grounds of authenticity and correlation with other elements of a prescriptive scheme of things will adapt themselves only tardily to any change in the situation or to any new bias in the drift of discipline. What happened in the matter of civil rights under the system of handicraft is an illustration in point. There need be little question but the eighteenth century scheme of Natural Rights was an outcome of the protracted discipline characteristic of the era of handicraft, and an adaptation to the exigencies of daily life under that system.