quantity of water at once; another must be fed by driblets; no one can say why.  One engine is a fac-simile of the other; yet each has its character and its peculiarities as truly as a man has.  You need to know your engine’s temper before driving it, just as much as you need to know that of your horse, or that of your friend.  I know, of course, there is a mechanical reason for this seeming caprice, if you could trace the reason.  But not one man in a thousand could trace out the reason.  And the phenomenon, as it presses itself upon us, really amounts to this:  that very complicated machinery appears to have a will of its own,—­appears to exercise something of the nature of choice.  But there is no machine so capricious as the human mind.  The great poet who wrote those beautiful verses could not do that every day.  A good deal more of what he writes is poor enough; and many days he could not write at all.  By long habit the mind may be made capable of being put in harness daily for the humbler task of producing prose; but you cannot say, when you harness it in the morning, how far or at what rate it will run that day.

Go and see a great organ of which you have been told.  Touch it, and you hear the noble tones at once.  The organ can produce them at any time.  But go and see a great man; touch him,—­that is, get him to begin to talk.  You will be much disappointed, if you expect, certainly, to hear anything like his book or his poem.  A great man is not a man who is always saying great things, or who is always able to say great things.  He is a man who on a few occasions has said great things; who on the coming of a sufficient occasion may possibly say great things again; but the staple of his talk is commonplace enough.  Here is a point of difference from machinery, with all machinery’s apparent caprice.  You could not say, as you pointed to a steam-engine, “The usual power of that engine is two hundred horses; but once or twice it has surprised us all by working up to two thousand.”  No; the engine is always of nearly the power of two thousand horses, if it ever is.  But what we have been supposing as to the engine is just what many men have done.  Poe wrote “The Raven”; he was working then up to two thousand horse power.  But he wrote abundance of poor stuff, working at about twenty-five.  Read straight through the volumes of Wordsworth, and I think you will find traces of the engine having worked at many different powers, varying from twenty-five horses or less up two thousand or more.  Go and hear a really great preacher, when he is preaching in his own church upon a common Sunday, and possibly you may hear a very ordinary sermon.  I have heard Mr. Melvill preach very poorly.  You must not expect to find people always at their best.  It is a very unusual thing that even the ablest men should be like Burke, who could not talk with an intelligent stranger for five minutes without convincing the stranger that he had talked for five