Sec. 11. There is even a way in which the very definiteness of Turner's knowledge adds to the mystery of his pictures. In the course of the first volume I had several times occasion to insist on the singular importance of cast shadows, and the chances of their sometimes gaining supremacy in visibility over even the things that cast them. Now a cast shadow is a much more curious thing than we usually suppose. The strange shapes it gets into--the manner in which it stumbles over everything that comes in its way, and frets itself into all manner of fantastic schism, taking neither the shape of the thing that casts it, nor of that it is cast upon, but an extraordinary, stretched, flattened, fractured, ill-jointed anatomy of its own--cannot be imagined until one is actually engaged in shadow-hunting. If any of these wayward umbrae are faithfully remembered and set down by the painter, they nearly always have an unaccountable look, quite different from anything one would have invented or philosophically conjectured for a shadow; and it constantly happens, in Turner's distances, that such strange pieces of broken shade, accurately remembered, or accurately invented, as the case may be, cause a condition of unintelligibility, quaint and embarrassing almost in exact proportion to the amount of truth it contains. Sec. 12. I believe the reader must now sufficiently perceive that the right of being obscure is not one to be lightly claimed; it can only be founded on long effort to be intelligible, and on the present power of _being_ intelligible to the exact degree which the nature of the thing admits. Nor shall we, I hope, any more have difficulty in understanding how the noble mystery and the ignoble, though direct opposites, are yet continually mistaken for each other--the last aping the first; and the most wretched artists taking pride in work which is simply slurred, slovenly, ignorant, empty, and insolent, as if it were nobly mysterious (just as a drunkard who cannot articulate supposes himself oracular); whereas the noble art-mystery, as all noble language-mystery, is reached only by intense labor. Striving to speak with uttermost truth of expression, weighing word against word, and wasting none, the great speaker, or writer, toils first into perfect intelligibleness, then, as he reaches to higher subject, and still more concentrated and wonderful utterance, he becomes ambiguous--as Dante is ambiguous,--half a dozen different meanings lightening out in separate rays from every word, and, here and there, giving rise to much contention of critics as to what the intended meaning actually was. But it is no drunkard's babble for all that, and the men who think it so, at the third hour of the day, do not highly honor _themselves_ in the thought.