It is this study which has given science its present-day prominence. In the world of intellect, doubtless, the most marked features in the history of the past century have been the extraordinary advances in scientific knowledge and investigation, and in the position held by the men of science with reference to those engaged in other pursuits. I am not now speaking of applied science; of the science, for instance, which, having revolutionized transportation on the earth and the water, is now on the brink of carrying it into the air; of the science that finds its expression in such extraordinary achievements as the telephone and the telegraph; of the sciences which have so accelerated the velocity of movement in social and industrial conditions—for the changes in the mechanical appliances of ordinary life during the last three generations have been greater than in all the preceding generations since history dawned. I speak of the science which has no more direct bearing upon the affairs of our everyday life than literature or music, painting or sculpture, poetry or history. A hundred years ago the ordinary man of cultivation had to know something of these last subjects; but the probabilities were rather against his having any but the most superficial scientific knowledge. At present all this has changed, thanks to the interest taken in scientific discoveries, the large circulation of scientific books, and the rapidity with which ideas originating among students of the most advanced and abstruse sciences become, at least partially, domiciled in the popular mind.