Since the improvement in the manufactory of cast-iron has brought that material into more frequent use, it may not be improper to mention something concerning the colour it ought to be painted. Its natural colour, after it is exposed to wet, is that of rusty iron, and the colour of rust indicates decay; when painted of a slate colour it resembles lead, which is an inferior metal to iron; and if white or green, it resembles wood: but if we wish it to resemble metal, and not appear of an inferior kind, a powdering of copper or gold dust on a green ground, makes a bronze, and perhaps it is the best colour for all ornamental rails of iron. In a cast-iron bridge at WHITTON, the effect of this bronze colour, mixed with gilding, * is admirable; and for the hand-rails of staircases it is peculiarly appropriate.
*[Those who have seen the gilded domes of Constantinople, mention them with admiration; and from the observations I have made on the effect of external gilding in large masses, I have often considered gilding the dome of St. Paul's as a subject worthy of this nation's wealth and glory. This idea will, I doubt not, excite ridicule from those who have never observed or studied the wonderful, the pleasing, the unexpected, and harmonious effect of gilding on smooth surfaces.]
