W was the 19th letter and was pronounced "wah"; there was an equivalent letter in the old Baybayin script of the Philippines. In the International Phonetic Alphabet, is used for the voiced labial-velar approximant. W is the symbol for the chemical element tungsten, after its German (and alternative English) name, "Wolfram". It is also the SI symbol for the watt, the standard unit of power. Double-u, whose name reflects stages in the letter's evolution when it was considered two of the same letter, a double U, is the only modern English letter whose name has more than one syllable. It is
Flux melting Flux melting In igneous petrology, flux melting occurs when water and other volatile components are added to hot solid rock. In engineering and metallurgy, flux is a substance, such as salt, that produces a low melting point mixture with a metal oxide. In the same way, the addition of water and other volatile compounds to rocks composed of silicate minerals lowers the melting temperature of those rocks. In subduction zones, the ultramafic rock of the upper mantle is melted by the addition of volatiles from the down-going plate. The subducting slab of oceanic crust carries water and other volatiles into