1911 Encyclopædia Britannica/Microcosmic Salt

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MICROCOSMIC SALT, or ammonium sodium hydrogen or tho phosphate, NH4NaHPO4·4H2O, so named by the alchemists because it is contained in the decomposing urine of man (the “ microcosm ”). It is interesting historically as being the raw material from which Brand prepared phosphorus, whence it is also called “ salt of phosphorus.” It may be obtained in large transparent crystals from a mixture of solutions of salammoniac and disodium phosphate, or by saturating a solution of mono sodium phosphate with ammonia. When heated to redness, it leaves a transparent glass of sodium meta phosphate, NaPO3, which like borax dissolves most metallic oxides, with formation of glasses that often exhibit characteristic colours, and which may be used in the qualitative analysis of substances. (See Chemistry, § Analytical.)