And having thus appealed to facts, we found further that in the nature of things no such destruction could follow; that what we call explanation in science is at bottom only a reduction of unfamiliar mysteries to terms of familiar mysteries, and that, since to the true imaginative mind, whether of poet or novelist, the mysteries of this world grow all the greater as they grow more familiar, the necessary effect of scientific explanations is at last the indefinite increase of food for the imagination. The modern imagination, indeed, shall still love mystery; but it is not the shallow mystery of those small darks which are enclosed by caves and crumbling dungeons, it is the unfathomable mystery of the sunlight and the sun; it is this inexplicable contradictory shadow of the infinite which is projected upon the finite; it is this multitudinous flickering of all the other _ego's_ upon the tissue of my _ego_: these are the lights and shades and vaguenesses of mystery in which the modern imaginative effort delights. And here I cannot help adding to what was said on this subject in the last lecture, by declaring to every young man who may entertain the hope of poethood, that at this stage of the world you need not dream of winning the attention of sober people with your poetry unless that poetry, and your soul behind it, are informed and saturated at least with the largest final conceptions of current science. I do not mean that you are to write "Loves of the Plants;" I do not mean that you are to versify Biology; but I mean that you must be so far instinct with the scientific thought of the time that your poetic conceptions will rush as it were from under these pure, cold facts of science like those Alpine torrents which flow out of glaciers. Or,--to change the figure for the better--just as the chemist, in causing chlorine and hydrogen to form hydrochloric acid, finds that he must not only put the chlorine and hydrogen together, but he must put them together in the presence of light in order to make them combine; so the poet of our time will find that his poetic combinations, his grandest syntheses of wisdom, own this law; and they, too, must be effected in the presence of the awful light of science.