The bread which I formerly ate nourished me; that is, a body of such sensible qualities was, at that time, endued with such secret powers; but does it follow that other bread must also nourish me at another time, and that like sensible qualities must also be attended with like secret powers? The consequence seems nowise necessary." And yet we eat our bread, day by day, without a doubt or a fear. We sow the grain and we reap the wheat, but for all the work is done in faith, and the whole process is steeped in mystery. In that scattering of the golden seed, what confidence is expressed in elements that we cannot see, in beneficent agencies that we cannot control, in results that are beyond our power, and that in their growth and development are full of wonder exceeding our wisdom. Give up faith; say that we will act only upon that which is demonstrated and known, say that we will walk only so far as sight reaches, and we completely separate the present from the future, and stop all the mechanism of practical life. But if we take a wider view of things, and consider this material universe in which we live, the great fact of mystery and the need of faith will be urged upon us by a larger and more impressive teaching. The more we learn of nature the more clearly is revealed to us this fact--that we know less than we thought we did; positively, we know more, but relatively we know less, because as we have advanced nature has stretched out into wider and wider relations. The department that was unknown to us yesterday is explored to-day. Yesterday, we thought it was all that remained to be explored, but the torch of investigation that guided us through it now flares out upon new regions we did not see before. Like one who goes with a candle into some immense cavern, presently a little circle becomes clear, the shadows vanish before him, and undefined forms grow distinct, he thinks he is near the end, when lo! what seemed a solid boundary of rock dissolves and floats away into a depth of darkness, the path opens into an immense void, new shapes of mystery start out, and he learns this much that he did not know before, that instead of being near the end, he is only upon the threshold. We do not mean to imply by this that we have no positive knowledge, or that we do not increase in knowledge. With every new discovery we positively know more and more. But the new discovery reveals the fact that more is yet to be known; it lays open new regions, it unfolds new relations that we had not before suspected.