'flat following are exemplideations of the difference of color communicated to the flame by different substances: Salts of potash color, the flame ziolet; soda. yellow; 1111lia, purplish, red; barytst, gellomish green; strontia, carmine; lime. brick red; compounds of phosphoric acid, Nora eic acid, and copper, green. The commonly occurring metallic oxides reducible by heating on charcoal alone in the inner dame of the blow-pipe are the oxides of zinc, silver, lead. copper. bismuth, and antimony; the principal ores not so reducible are the alkalies and alkaline earths, as also the oxides of iron, manganese, and chro mium. The fluxes generally used in blow-pipe experiments are either carbonate of soda, boraix (biborate of soda). or th1 ammonia-phosphate of Soda. otherwise called microcosmic salt pi. v.). l'ite carbonate of soda, when heated on platinum-wire in the oxidizing flame, forms with silica a colorless glass; with oxide of antimony, a ,shire bead, etc. The following metals are reduced from their eompourals when heated with carbonate of soda on charcoal in the inner flame of the blo w-pipe, viz.: nickel,cobalt, iron, molybdenum, tungsten, copper, tits silver, gold, and platinum. When compounds of %AIM. lead. bis
muth, arsenic. antimony. tellurium, and cadmium are similarly treated, these metals are also formed, but being volatile, they pass off in vapor at the high temperature to which they are exposed.
Borax, as a Jinx, is generally mixed with the substance under examination, and placed on platinum-wire. When thus heatial in either of the flames. baryta, stroutia, Iiine, magnesia, alumina, and silica. yield colorless bear's; coital( gives a fine bloc color; copper, a green; etc. 11 itli microcosmic salt, the results obtained are generally similar to those with borax, and need not be specially mentioned. as the tesi is implicit tin the same way. The blowpipe has been long used by goldsmiths and jewelers tor soldering metals, and by glass-blowers in fusing and sealing gloss-tithes, etc.; it has also beea applied in qualitative analysis for many years, but more recently chemists (especially Plattner) have devoted their attention to its 11Se. and have even employed it with great success in gnanlitatire chemical analysis; the advantages being: that only a very satrap quantity of material is required to operate upon, whilst the results tinty be obtained with great rapidity and considerable accuracy.