As far as I know he has never written on any scientific subject. For aught I am aware of, he may know nothing of mathematics or chemistry, of comparative anatomy or geology. For aught I am aware of, he may know a great deal about them all, and, like a wise man, hold his tongue, and give the world merely the results in the form of general thought. But this I know; that his writings are instinct with the very spirit of science; that he has taught men, more than any living man, the meaning and end of science; that he has taught men moral and intellectual courage; to face facts boldly, while they confess the divineness of facts; not to be afraid of Nature, and not to worship nature; to believe that man can know truth; and that only in as far as he knows truth can he live worthily on this earth. And thus he has vindicated, as no other man in our days has done, at once the dignity of Nature and the dignity of spirit. That he would have made a distinguished scientific man, we may be as certain from his writings as we may be certain, when we see a fine old horse of a certain stamp, that he would have made a first-class hunter, though he has been unfortunately all his life in harness. Therefore, did I try to train a young man of science to be true, devout, and earnest, accurate and daring, I should say--Read what you will: but at least read Carlyle. It is a small matter to me--and I doubt not to him--whether you will agree with his special conclusions: but his premises and his method are irrefragable; for they stand on the "voluntatem Dei in rebus revelatam"--on fact and common sense. And Mr. Carlyle's writings, if I am correct in my estimate of them, will afford a very sufficient answer to those who think that the scientific habit of mind tends to irreverence. Doubtless this accusation will always be brought against science by those who confound reverence with fear. For from blind fear of the unknown, science does certainly deliver man. She does by man as he does by an unbroken colt. The colt sees by the road side some quite new object--a cast-away boot, an old kettle, or what not. What a fearful monster! What unknown terrific powers may it not possess! And the colt shies across the road, runs up the bank, rears on end; putting itself thereby, as many a man does, in real danger. What cure is there? But one; experience. So science takes us, as we should take the colt, gently by the halter; and makes us simply smell at the new monster; till after a few trembling sniffs, we discover, like the colt, that it is not a monster, but a kettle. Yet I think, if we sum up the loss and gain, we shall find the colt's character has gained, rather than lost, by being thus disabused. He learns to substitute a very rational reverence for the man who is breaking him in, for a totally irrational reverence for the kettle; and becomes thereby a much wiser and more useful member of society, as does the man when disabused of his superstitions.