Mark Twain's humour is purely American. It is not the humour of Washington Irving, which resembles that of Addison and Thackeray; it is not delicate and indirect. It is genial, sometimes outrageous, mirth--laughter holding both his sides. I have found it difficult to read him in a library or on a street-car, for explosions of pent-up mirth or a distorted face are apt to attract unpleasant attention in such public places. Mark Twain's humour is boisterous, uproarious, colossal, overwhelming. As has often been remarked, the Americans are not naturally a gay people, like the French; nor are we light-hearted and careless, like the Irish and the Negro. At heart, we are intensely serious, nervous, melancholy. For humour, therefore, we naturally turn to buffoonery and burlesque, as a reaction against the strain and tension of life. Our attitude is something like that of the lonely author of the _Anatomy of Melancholy_, who used to lean over the parapet of Magdalen Bridge, and shake with mirth at the obscene jokes of the bargemen. We like Mark Twain's humour, not because we are frivolous, but because we are just the reverse. I have never known a frivolous person who really enjoyed or appreciated Mark Twain. The essence of Mark Twain's humour is Incongruity. The jumping frog is named Daniel Webster; and, indeed, the intense gravity of a frog's face, with the droop at the corners of the mouth, might well be envied by many an American Senator. When the shotted frog vainly attempted to leave the earth, he shrugged his shoulders "like a Frenchman." Bilgewater and the Dolphin on the raft are grotesquely incongruous figures. The rescuing of Jim from his prison cell is full of the most incongruous ideas, his common-sense attitude toward the whole transaction contrasting strangely with that of the romantic Tom. Along with the constant incongruity goes the element of surprise--which Professor Beers has well pointed out. When one begins a sentence, in an apparently serious discussion, one never knows how it will end. In discussing the peace that accompanies religious faith, Mark Twain says that he has often been impressed with the calm confidence of a Christian with four aces. Exaggeration--deliberate, enormous hyperbole--is another feature. Rudyard Kipling, who has been profoundly influenced by Mark Twain, and has learned much from him, often employs the same device, as in _Brugglesmith_. Irreverence is also a noteworthy quality. In his travel-books, we are given the attitude of the typical American Philistine toward the wonders and sacred relics of the Old World, the whole thing being a gigantic burlesque on the sentimental guide-books which were so much in vogue before the era of Baedeker. With such continuous fun and mirth, satire and burlesque, it is no wonder that Mark Twain should not always be at his best. He is doubtless sometimes flat, sometimes coarse, as all humorists since Rabelais have been. The wonder is that his level has been so high.