less careful examination would never have detected at all, for an intentional irregularity; quite possible to misinterpret an obscure passage in a picture, which a less earnest observer would never have tried to interpret. But mistakes of this kind--honest, enthusiastic mistakes--are never harmful; because they are always made in a true direction,--falls forward on the road, not into the ditch beside it; and they are sure to be corrected by the next comer. But the blunt and dead mistakes made by too many other writers on art--the mistakes of sheer inattention, and want of sympathy--are mortal. The entire purpose of a great thinker may be difficult to fathom, and we may be over and over again more or less mistaken in guessing at his meaning; but the real, profound, nay, quite bottomless, and unredeemable mistake, is the fool's thought--that he had no meaning. I do not refer, in saying this, to any of my statements respecting subjects which it has been my main work to study: as far as I am aware, I have never yet misinterpreted any picture of Turner's, though often remaining blind to the half of what he had intended: neither have I as yet found anything to correct in my statements respecting Venetian architecture; [Footnote: The subtle portions of the Byzantine Palaces, given in precise measurements in the second volume of the "Stones of Venice," were alleged by architects to be accidental irregularities. They will be found, by every one who will take the pains to examine them, most assuredly and indisputably intentional,--and not only so, but one of the principal subjects of the designer's care.] but in _casual references_ to what has been quickly seen, it is impossible to guard wholly against error, without losing much valuable observation, true in ninety-nine cases out of a hundred, and harmless even when erroneous. APPENDIX II. REYNOLDS' DISAPPOINTMENT. It is very fortunate that in the fragment of Mason's MSS., published lately by Mr. Cotton in his "Sir Joshua Reynolds' Notes," [Footnote: Smith, Soho Square, 1859.] record is preserved of Sir Joshua's feelings respecting the paintings in the window of New College, which might otherwise have been supposed to give his full sanction to this mode of painting on glass. Nothing can possibly be more curious, to my mind, than the great painter's expectations; or his having at all entertained the idea that the qualities of colour which are peculiar to opaque bodies could be obtained in a transparent medium; but so it is: and with the simplicity and humbleness of an entirely great man he hopes that Mr. Jervas on glass is to excel Sir Joshua on canvas. Happily, Mason tells us the result.