Palladium
This metal closely resembles platinum in color and appearance; it is also very malleable and ductile. It is not so dense as platinum, being only 11.8, and it is more easily oxidized than that metal, but cannot be melted at ordinary temperatures. Palladium readily alloys with other metals. When alloyed with silver it is very suitable for the graduations on mathematical instruments, etc. It is used also as a galvanizing agent for protecting other metals when amalgamated with mercury, the iron or other articles being cleansed previously as for zinking. See METALS; ZINKING. Pan, or Kettle, is usually a wide, shallow, round or spherical-shaped vessel, of cast-iron or other metal, employed in the manufacture of sugar, salt chemicals, soap, tin-plate, and in the various processes connected with metallurgy. For sugar-refining there are evaporating-pans, vacuum-pans, condensing-kettles, vats, coolers, etc. Salt-pans are usually very wide and shallow, and are set in rows over a furnace. The brine is pumped into them, the heat evaporates the water, and the salt precipitates. The chemical works employ large numbers of pans of different shapes, heavy and light, such as the flat furnace-pans, 8 to 10 feet across, which are sometimes over 6 inches thick at the crown; lighter ones, as crystallizing cones, etc., are used in large numbers. Pans for soap-making are termed "boilers," and consist of a deep, circular, tapered pan with a spherical bottom. Brackets cast on the sides serve to set the pan on standards over the fire. Pans used for tin-plate are of cast iron. They are set in a row, and are named, respectively, the tin-pot, wash-pot, grease-pot, pan, and list-pot. Pans for metallurgical purposes are termed amalgamators, being usually an open, flat-bottomed, pan in which the pulverized ore and mercury are ground together between slabs of stone or metal. (See AMALGAMATION.) Owing to the great demand for castings of this class, much ingenuity has been practised for moulding them readily, resulting in well-established methods of production, which far excel the ordinary systems of moulding. See KETTLE; CASING.
Paper-moulding consists of grinding old paper along with other materials into a pulp, which by the aid of presses and other machinery is moulded into the required form, dried, and then subjected to the processes of sizing, decorating, etc. It is used extensively in the production of architectural ornaments, etc., being less brittle than plaster for that purpose. By mixing white of egg, sulphate of iron, glue, or quicklime, etc., with the pulp it is partly made waterproof, and to make it almost fireproof it only requires a further admixture of borax and sulphate of soda. Another method of producing articles in paper is to glue sheets of paper together and then subject the whole to powerful pressure in dies accurately fashioned to the form of article to be made. This operation is performed when the sheets are moist, which admits of the requisite curvature and flexure without damage to the article, which when dry becomes as hard as board, and is then ready to be operated upon by the japanners, inlayers, and other artists in ornamentation.