Professor G. Croom Robertson recently commenced a course of thirty lectures to ladies on Psychology and Logic, at the Hall, 15, Lower Seymour Street, Portman Square. Urged, it may be, rather by a desire to see whether ladies would be attracted by such a subject, and, if so, what psychological ladies were like, than by any direct interest in the matters themselves, I applied to the hon. secretary, inquiring whether the inferior sex were admissible; and was answered by a ticket admitting one's single male self and a party of ladies a discretion. The very entrance to the hall--nay, the populous street itself--removed my doubts as to whether ladies would be attracted by the subjects; and on entering I discovered that the audience consisted of several hundred ladies, and two unfortunate--or shall it not rather be said privileged?--members of the male sex. The ladies were of all ages, evidently matrons as well as spinsters, with really nothing at all approaching a "blue stocking" element; but all evidently bent on business. All were taking vigorous notes, and seemed to follow the Professor's somewhat difficult Scotch diction at least as well as our two selves, who appeared to represent not only the male sex in general, but the London press in particular. Professor Robertson commenced by a brief and well-timed reference to the accomplished Hypatia, familiar to ladies from Kingsley's novel--in the days when ladies used to read novels--and also the Royal ladies whom Descartes and Leibnitz found apter disciples than the savants. It was, however, he remarked, an impertinence to suppose that any apology was needed for introducing such subjects before ladies. He plunged therefore at once in medias res, and made his first lecture not a mere isolated or introductory one, but the actual commencement of his series. Unreasoned facts, he said, formed but a mere fraction of our knowledge--even the simplest processes resolving themselves into a chain of inference. Truth is the result of logical reasoning; and not only truth, but truth _for all_. The sciences deal with special aspects of truth. These sciences may be arranged in the order--1. Mathematics; 2. Physics; 3. Chemistry; 4. Biology--each gradually narrowing its sphere; the one enclosed, so to say, in the other, and each presupposing those above it. Logic was presupposed in all. Each might be expressed by a word ending in "logy," therefore logic might be termed the "science of sciences." The sciences were special applications of logic. Scientific men speak lightly of logic, and say truth can be discovered without it. This is true, but trivial. We may as well object to physiology because we can digest without a knowledge of it; or to arithmetic, because it is possible to reckon without it. Scientific progress has been great; but its course might have been strewn with fewer wrecks had its professors been more generally logicians. But then logic presupposes something else. We have