To speak of small things as though they were large is, in a general way, to exaggerate.  Exaggeration is always comic when prolonged, and especially when systematic; then, indeed, it appears as one method of transposition.  It excites so much laughter that some writers have been led to define the comic as exaggeration, just as others have defined it as degradation.  As a matter of fact, exaggeration, like degradation, is only one form of one kind of the comic.  Still, it is a very striking form.  It has given birth to the mock-heroic poem, a rather old-fashioned device, I admit, though traces of it are still to be found in persons inclined to exaggerate methodically.  It might often be said of braggadocio that it is its mock-heroic aspect which makes us laugh.

Far more artificial, but also far more refined, is the transposition upwards from below when applied to the moral value of things, not to their physical dimensions.  To express in reputable language some disreputable idea, to take some scandalous situation, some low-class calling or disgraceful behaviour, and describe them in terms of the utmost “Respectability,” is generally comic.  The English word is here purposely employed, as the practice itself is characteristically English.  Many instances of it may be found in Dickens and Thackeray, and in English literature generally.  Let us remark, in passing, that the intensity of the effect does not here depend on its length.  A word is sometimes sufficient, provided it gives us a glimpse of an entire system of transposition accepted in certain social circles and reveals, as it were, a moral organisation of immorality.  Take the following remark made by an official to one of his subordinates in a novel of Gogol’s, “Your peculations are too extensive for an official of your rank.”

Summing up the foregoing, then, there are two extreme terms of comparison, the very large and the very small, the best and the worst, between which transposition may be effected in one direction or the other.  Now, if the interval be gradually narrowed, the contrast between the terms obtained will be less and less violent, and the varieties of comic transposition more and more subtle.

The most common of these contrasts is perhaps that between the real and the ideal, between what is and what ought to be.  Here again transposition may take place in either direction.  Sometimes we state what ought to be done, and pretend to believe that this is just what is actually being done; then we have irony.  Sometimes, on the contrary, we describe with scrupulous minuteness what is being done, and pretend to believe that this is just what ought to be done; such is often the method of humour.  Humour, thus denned, is the counterpart of irony.  Both are forms of satire, but irony is oratorical in its nature, whilst humour partakes of the scientific.  Irony is emphasised the higher we allow ourselves to be uplifted by the idea of the good that ought to