(1.) The surface of the iron is prepared and coated with two coats of red lead or oxide of iron paint. (2.) An adhesive composition composed of the ingredients mentioned below is then applied rather more thickly than ordinary paint, and well sprinkled with granulated cork. (3.) After 4 days a coat of white zinc paint much thinner than ordinary paint is applied, then one coat of distemper.

Proportions of adhesive composition to make 112 lbs : -

White lead, 22 lbs.; driers, 101/2 lbs.; boiled oil, 33/4 gallons; sperm yellow, 44 lbs.; resin, 21/2 lbs.

Luminous Paint is a preparation of sulphide of calcium made up with varnish. Oil destroys its properties, and care should be taken to apply it only to perfectly clean surfaces free from lead paint or corrosion.

The characteristic of this paint in presenting a luminous surface for many hours or even days after the source of light has been cut off is well known, and it is capable of various obviously useful applications.

The action is supposed to be due to "molecular vibration set up in the body by waves of light rich in actinic rays, which vibration is maintained in the dark, and is the cause of luminosity so long as the energy remains active and not absorbed."