XVII. Painting, however, is not the only mode in which material may be concealed, or rather simulated; for merely to conceal is, as we have seen, no wrong. Whitewash, for instance, though often (by no means always) to be regretted as a concealment, is not to be blamed as a falsity. It shows itself for what it is, and asserts nothing of what is beneath it. Gilding has become, from its frequent use, equally innocent. It is understood for what it is, a film merely, and is, therefore, allowable to any extent. I do not say expedient: it is one of the most abused means of magnificence we possess, and I much doubt whether any use we ever make of it, balances that loss of pleasure, which, from the frequent sight and perpetual suspicion of it, we suffer in the contemplation of anything that is verily of gold. I think gold was meant to be seldom seen and to be admired as a precious thing; and I sometimes wish that truth should so far literally prevail as that all should be gold that glittered, or rather that nothing should glitter that was not gold. Nevertheless, nature herself does not dispense with such semblance, but uses light for it; and I have too great a love for old and saintly art to part with its burnished field, or radiant nimbus; only it should be used with respect, and to express magnificence, or sacredness, and not in lavish vanity, or in sign painting. Of its expedience, however, any more than of that of color, it is not here the place to speak; we are endeavoring to determine what is lawful, not what is desirable. Of other and less common modes of disguising surface, as of powder of lapis lazuli, or mosaic imitations of colored stones, I need hardly speak. The rule will apply to all alike, that whatever is pretended, is wrong; commonly enforced also by the exceeding ugliness and insufficient appearance of such methods, as lately in the style of renovation by which half the houses in Venice have been defaced, the brick covered first with stucco, and this painted with zigzag veins in imitation of alabaster. But there is one more form of architectural fiction, which is so constant in the great periods that it needs respectful judgment. I mean the facing of brick with precious stone. XVIII. It is well known, that what is meant by a church's being built of marble is, in nearly all cases, only that a veneering of marble has been fastened on the rough brick wall, built with certain projections to receive it; and that what appear to be massy stones, are nothing more than external slabs.