Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/72

64 to have been originally made from a natural volcanic product at Naples. It is not so brilliant as chrome, but has the same characteristics. King's yellow is made from arsenic, and is therefore a dangerous color to handle, or use for internal work. It is not durable, and it injures several other colors when mixed with them. Chinese yellow, arsenic yellow and yellow orpiment are other names for this yellow. Yellow ochre is a natural clay colored by oxide of iron, and found abundantly in many parts of the world. It is not very brilliant, but is well suited for distemper work, as it is not affected by light or air. It does not lose its

color when mixed with lime washes as many other colors do. There are several varieties of ochres, all having the same characteristics differing only in color which varies from a golden to a dark brown.

All the hues and tints, from the palest lemon cadmium to the orange red, are due to one compound only of cadmium, namely the sulphide, which contains 112 parts by weight of cadmium to 32 parts of sulphur. As commonly prepared cadmium yellow is of an orange hue; when this compound separates slowly from a solution, or is made in any way to take a dense or aggregated form, it becomes