a method of painting in relievo on walls, so as to endure the weather.

It is performed with water-colours on fresh plaster, or on a wall laid with mortar not yet dry. This sort of painting has a great advantage by its incorporating with the mortar, and, drying along with it, becomes very durable.

The compost should be made of rubbish stones mixed with well-burnt flint, or lime and water: but the saltiness of the lime must be washed out, by pouring water frequently on it. But this should not be done in moist weather.

To prevent the plaster from peeling, strike into the joints of the wall stumps of horse-nails six inches distant from each other. First plaster the walls pretty thick; then let it dry for some time, the design and colours being first ready prepared. This painting is chiefly performed on walls and vaults newly plastered with lime and sand; and the plaster is only to be put on in proportion as the painting proceeds.

Plaster the wall a second time, about the thickness of half a crown, only so much as you intend to work upon; and while it is wet, work the colours therein, which will incorporate with the plaster so as never to wash out.

The painting must be worked with a free hand, and your colours made high enough at first, as there can be no alteration made after the first painting.

In this work scarce any thing else is used but earths, which still retain their colour, defending it from the burning and salt of the lime. The colours are white, made of lime flaked some time, and white marble dull, red and yellow ocher, violet red, verditer, lapis lazuli, smalt, black Spanish brown, Spanish white, &c. all which are grounded and worked up with water.

The brushes and pencils for this work must be long and soft, or else they will rake and raze the painting: the colours must be full and flowing from the brush, and the design or cartoon must be perfect in the paper-copy.