The limits of Browning's art, like the limits of Whitman's, can therefore be understood by considering his mental habit. Both poets had powerful imaginations, but the type of their imaginations was low. In Whitman imagination was limited to marshalling sensations in single file; the embroideries he made around that central line were simple and insignificant. His energy was concentrated on that somewhat animal form of contemplation, of which, for the rest, he was a great, perhaps an unequalled master. Browning rose above that level; with him sensation is usually in the background; he is not particularly a poet of the senses or of ocular vision. His favourite subject-matter is rather the stream of thought and feeling in the mind; he is the poet of soliloquy. Nature and life as they really are, rather than as they may appear to the ignorant and passionate participant in them, lie beyond his range. Even in his best dramas, like "A Blot in the 'Scutcheon" or "Colombe's Birthday," the interest remains in the experience of the several persons as they explain it to us. The same is the case in "The King and the Book," the conception of which, in twelve monstrous soliloquies, is a striking evidence of the poet's predilection for this form. The method is, to penetrate by sympathy rather than to portray by intelligence. The most authoritative insight is not the poet's or the spectator's, aroused and enlightened by the spectacle, but the various heroes' own, in their moment of intensest passion. We therefore miss the tragic relief and exaltation, and come away instead with the uncomfortable feeling that an obstinate folly is apparently the most glorious and choiceworthy thing in the world. This is evidently the poet's own illusion, and those who do not happen to share it must feel that if life were really as irrational as he thinks it, it would be not only profoundly discouraging, which it often is, but profoundly disgusting, which it surely is not; for at least it reveals the ideal which it fails to attain.