English pewter century. Lead was removed from the composition in 1974, by BS5140, reinforced by the European directive BSEN611 in 1994. Until the end of the 18th century, the only method of manufacture was by casting and the soldering of components. From the last quarter of the 18th century, improvement in alloys (e.g. britannia metal) and techniques allowed objects to be made from pewter by stamping and spinning. English pewter While the term pewter covers a range of tin-based alloys, the term English pewter has come to represent a strictly-controlled alloy, specified by BSEN611-1 and British Standard 5140, consisting mainly of tin
Ceramic discharge metal-halide lamp discharge is contained in a ceramic tube, usually made of sintered alumina, similar to what has been used in the high pressure sodium lamp. During operation, the temperature of this ceramic tube can exceed 1200 kelvins. The ceramic tube is filled with mercury, argon and metal-halide salts (for example, sodium iodide). Because of the high wall temperature, the metal halide salts are partly vaporized. Inside the hot plasma, these salts are dissociated into metallic atoms and iodine. The metallic atoms are the main source of light in these lamps, creating a bluish light that is close to daylight with a