The only plausible part of his Historical Survey, and that which, in our apprehension, is the most likely to make some transient impression on the popular mind, is his elaborate attempt to show, with regard to each branch of Science, in detail, that it was enveloped during its infancy in a cloud of superstition; and that just in proportion as the light shone more clearly, or was more distinctly discerned, the cloud was gradually dissipated and dispersed, until, one after another, they were all emancipated from their supposed connection with supernatural causes, and reduced under fixed natural laws. Confounding Theology with Superstition, or failing, at least, to discriminate duly between the two, M. Comte draws a vivid picture of the successive inroads which Science has made on the consecrated domain of Religion, and represents the one as receding just in proportion as the other advances. For as the darkness disappears before the rising sun, whose earliest rays gild only the loftier mountain peaks, but whose growing brightness spreads over the lowly valleys and penetrates the deepest recesses of nature, so Theology gradually retires before the advance of Science, which first conquers and brings under the rule of natural law the simplest and least complicated branches, such as Mechanics and Astronomy; then attacks the more complex, such as Chemistry and Physiology; and, last of all, advances to the assault of the most difficult, such as Ethics and Sociology; until, having emancipated each of them successively from their previous connection with supernatural beliefs, it effects the entire elimination of Theology, first from the philosophic, and afterwards from the popular creed of mankind. M. Comte conceives that the religious spirit has been steadily decreasing throughout the whole course of human development, from the time when it was universal, in the form of Fetishism, till it reached its most abstract, but least influential form in Monotheism; and that now the period of its decline and fall has arrived, when it is subjected to the powerful solvent of a Metaphysical and Skeptical Philosophy, and when its ultimate extinction is certain under the action of Positive Science.