discoloured, and cannot be washed down, so distemper is best suited to temporary and interior decoration. The technique of painting on distempered surfaces blends watercolours with whiting and glue. "The colours are mixed with whitening, or finely-ground chalk, and tempered with size. The whitening makes them opaque and gives them 'body,' but is also the cause of their drying light ... a source of considerable embarrassment to the inexperienced eye is that the colours when wet present such a different appearance from what they do when dry."

Many