Definition of microcosmic salt in US English:

microcosmic salt

noun

Chemistry
  • A white crystalline salt obtained from human urine.

    Hydrated sodium ammonium hydrogen phosphate; chemical formula: HNaNH₄PO₄·4H₂O

    • ‘The fluxes used to make beads are borax (available from the drugstore is pure enough for this type of work), salt of phosphorus (also called microcosmic salt), and sodium carbonate (called soda).’
    • ‘In addition to his work on constant proportions, Proust isolated crystalline grape sugar and mannite, showed that microcosmic salt contains soda, and isolated leucine from the products of putrefaction of casein.’
    • ‘The fluorine in this mineral was not certainly recognized by the blowpipe test, using a flux of microcosmic salt, the well-known etching-power of phosphoric acid itself standing in the way of this.’
    • ‘However Dalton did make some contributions on microcosmic salt and on a new method of analysing sugar.’
    • ‘A test similar to the borax bead test is often made using microcosmic salt.’

Origin

Late 18th century: translating Latin sal microcosmicus.

Pronunciation

microcosmic salt

/ˌmīkrəˌkäzmik ˈsôlt/