We have begun to recognise some of the chief letters of this alphabet, and even to put them two and two together; and, like an intelligent but somewhat conceited child, we are very proud of our achievement. Like such a child we have not yet, however, completely grasped the fact that these letters are only symbols, but look upon them with intense awe as the great thing in the world, meaning of course our world. We look with a sort of adoration towards those pages in which there are words of two syllables, and are ready to fall down at the feet of that older and wiser child who has penetrated into the depths of such profound mysteries. Our belief is that all knowledge is made for the alphabet just as the little musician believes that all music is made for the piano. 237. Life, then, whatever be its nature, may be supposed to penetrate into the structural depths of the universe. Its seat is in a region inaccessible to human inquiry, and equally inaccessible, we may well suppose, to the inquiries of the higher created intelligences. Intimations of its presence are no doubt constantly emerging from this region of thick darkness into the objective universe, but when they have reached it they obey the ordinary laws of phenomena, according to which a material effect implies a material antecedent. Notwithstanding all this, life exists just as surely as the Deity exists. For we have subjected both these mysteries to the same process, and have found it as difficult to rid ourselves of the one as of the other. We have driven the creative operation of the Great First Cause into the durational depths of the universe,—into the eternity of the past,—but for all that we have not got rid of God. In like manner we have driven the mystery of life into the structural depths of the universe,—that region of thick darkness which no created eye is able to pierce,—but we have not got rid of life, nor are we likely to do so. Before concluding this digression upon the place of life, let us briefly review the attempts made to account for the origin of life by those who have yet fallen short of the scientific conception of an Unseen Universe. 238. Sir W. Thomson has gone further than any one else in such inquiries. We have already alluded to his attempt to explain the origin of the material universe by the vortex-ring hypothesis, and also to his other attempt to explain gravitation by the modification of the hypothesis of ultra-mundane corpuscles. If we add to these his attempt to explain the origin of life as consistently as possible with the principle of Continuity, we think it must be acknowledged that he is a true pioneer in such inquiries as those of this volume as well as in the more ordinary branches of Physical Science.