--Scientific knowledge, even in the most modest persons, has mingled with it a something which partakes of insolence. Absolute, peremptory facts are bullies, and those who keep company with them are apt to get a bullying habit of mind;--not of manners, perhaps; they may be soft and smooth, but the smile they carry has a quiet assertion in it, such as the Champion of the Heavy Weights, commonly the best-natured, but not the most diffident of men, wears upon what he very inelegantly calls his "mug." Take the man, for instance, who deals in the mathematical sciences. There is no elasticity in a mathematical fact; if you bring up against it, it never yields a hair's breadth; everything must go to pieces that comes in collision with it. What the mathematician knows being absolute, unconditional, incapable of suffering question, it should tend, in the nature of things, to breed a despotic way of thinking. So of those who deal with the palpable and often unmistakable facts of external nature; only in a less degree. Every probability--and most of our common, working beliefs are probabilities--is provided with _buffers_ at both ends, which break the force of opposite opinions clashing against it; but scientific certainty has no spring in it, no courtesy, no possibility of yielding. All this must react on the minds that handle these forms of truth. --Oh, you need not tell me that Messrs. A. and B. are the most gracious, unassuming people in the world, and yet preëminent in the ranges of science I am referring to. I know that as well as you. But mark this which I am going to say once for all: If I had not force enough to project a principle full in the face of the half dozen most obvious facts which seem to contradict it, I would think only in single file from this day forward. A rash man, once visiting a certain noted institution at South Boston, ventured to express the sentiment, that man is a rational being. An old woman who was an attendant in the Idiot School contradicted the statement, and appealed to the facts before the speaker to disprove it. The rash man stuck to his hasty generalization, notwithstanding. [--It is my desire to be useful to those with whom I am associated in my daily relations. I not unfrequently practise the divine art of music in company with our landlady's daughter, who, as I mentioned before, is the owner of an accordion. Having myself a well-marked barytone voice of more than half an octave in compass, I sometimes add my vocal powers to her execution of: "Thou, thou reign'st in this bosom,"--