3/4 lb. of mottled soap to 1 gal. of water. This composition to be laid over the brickwork steadily and carefully with a large flat brush, so as not to form a froth or lather on the surface. The wash should remain 24 hours, to become dry. Mix 1/2 lb. of alum with 4 gals, of water, leave it to stand for 24 hours, and then apply it in the same manner over the coating of soap. Let this be done in dry weather.