Sentence Examples


  • The inferior varieties of commercial "white lead" are produced by mixing the genuine article with more or less of finely powdered heavy spar or occasionally zinc-white (ZnO).
  • It forms colourless, transparent rhombohedra, like those of Iceland spar; the angles are nearly equal to right angles, being 73° 30', so that the crystals look like cubes: hence the name of "cubic saltpetre."
  • Second in importance is the carbonate, calamine (q.v.) or zinc spar, which at one time was the principal ore; it almost invariably contains the carbonates of cadmium, iron, manganese, magnesium and calcium, and may be contaminated with clay, oxides of iron, galena and calcite; "white calamine" owes its colour to much clay; "red calamine" to admixed iron and manganese oxides.
  • He discovered double refraction in Iceland spar (Experimenta crystalli islandici disdiaclastici, Copenhagen, 1669).
  • Besides the invention of the prism known by his name ("A method of increasing the divergence of the two rays in calcareous spar, so as to produce a single image," New Edin.
 

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