contain more than traces of base metals, al· though the marking laws permit a 1.5% maxi· mum base·metals content for unsoldered articles.

Platinum has many industrial uses of importance to every-day life. In fabrics, clothing and tires, we utilize great quantities of rayon fiber. This fiber is produced from viscose by extruding the alkaline fluid into an acid bath through very tiny holes in spinnerets made of precious metal alloys containing up to 90% platinum. Wire gauze, made of 90% platinum and 10% rhodium, serves as a catalyst in making nitric acid, an important chemical essential to the production of fertilizers used in farming. Platinum alloys are used in making and handling molten glass during manufacture of electric light bulbs, glass fiber, optical glass, etc.

PALLADIUM

Pure palladium, an element discovered in 1803, is a white, ductile metal that melts at 2829°F. It is lighter than gold and all the other platinum metals, weighing 0.4343 lb. or 127 dwt. per cu. in.

Produced in smaller quantity than platinum,

palladium is an important member of the platinum group of metals each of which is a separate and distinct precious metal having its own properties. The lightness of palladium is a ready means of distinguishing palladium from platinum.

The use of palladium in jewelry dates from modern times. It is a new jewelry metal as compared to gold which was used for jewelry thousands of years ago. Jewelry craftsmen eliminate excess weight from ear-clips, brooches, etc. by using palladium. Diamond setters like its working properties.

For making jewelry, an alloy of palladium hardened with ruthenium is generally used. The composition of 95.5% palladium" and 4.5% ruthenium is well suited to jewelry, the cost per piece being only a little higher than 14K gold after allowing for the lightness of palladium. This alloy, known as "jewelry palladium," has the ductility needed to accomplish the manufacture of intricate parts, to facilitate the setting of precious stones, and to minimize the risk of chipping gems during the setting operation. Its hardness and strength insure satisfactory service for the user.