The publication in 1859 of Darwin’s _Origin of Species_ persuaded the men of that time, rightly or wrongly, that science and religion were very intimately connected, and science, at one blow, obtained a degree of public attention without precedent in its history. The interest thus evoked was not always very intelligent, but it was intense and widely diffused; it extended to other branches of science, influenced the educational system of the country and gave rise to an enormous extension of “popular” science lectures and articles. This popular interest was of a different kind from the leisurely interest previously shown by the cultured classes. The latter was, indeed, much more genuinely an interest in science for its own sake; the former had a different emotional basis and was merely the diversion of an interest in religious or social questions. There is a controversial air about nearly all the popular scientific writings of that time; the scientific man, like his audience, was fully aware that he was talking about a good deal more than the ostensible subject of discussion. Science, the creature of the least popular of man’s activities, patient and unprejudiced ratiocination, became associated with violent emotions. With Biology and Geology this association was inevitable and immediate; their subject-matter happened to be that of the first few chapters of Genesis. But the more exact sciences, when public attention turned their way, could offer no such excitements. They seem to have compromised by specialising on “marvels.” The “Marvels of Science” became a familiar heading, and the unsophisticated public were stunned by figures: the distances of the stars, the number of molecules in a cubic centimetre of water, the weight, in tons, of the earth, the incredible minuteness of light-waves, and so on, the whole object of such discourses being, as Maxwell unkindly put it, to prevent the audience realising that intellectual exhaustion had set in until the hour had elapsed.