When we talk of the material world, especially in its relation to the constantly developing wants of man, we talk simply of the kitchen and larder of humanity. We have not ascended into the drawing-room, or conservatory. The moment we step out of the consideration of manifested nature, we come into a world which may neither be weighed nor measured--the world of thought. I suppose that no author has ever entered a large library and stood in its alcoves and studied its titles long without asking himself the question: "what is there left for me to do?" It seems as if men had been reaching in all directions for the discovery of thought since time began, and as if there were absolutely nothing new to be said upon any subject. Yet every age has always demanded its peculiar food, and every age has managed to get it. Certain great and peculiarly fruitful subjects, blowing in the sea of thought, have attracted whole fleets of authors for many years, and they are doubtless chased away no more to return; but, here and there, while time shall last, strong men will bore down to deposits of thought unsuspected by any of the preceding generations of men, and there will gush up streams to light the nations of the world. For the world of thought is, by its nature, exhaustless. The world of thought is the world in which God lives, and it is infinite like himself. We reach our hands out into the dark in any direction, and find a thought. It was God's before it was ours; and on beyond that thought, lies another, and still another, _ad infinitum_. If our arms were long enough, we should be able to grasp them as well as the first. All that it wants is the long arm to give us the command of deposits that would astonish the world. Authors have become eminent according to their power to reach further than others out into the infinite atmosphere of thought which envelops them.