Phosphorus

Bologna phosphorus (Chem.), sulphide of barium, which shines in the dark after exposure to light; -- so called because this property was discovered by a resident of Bologna. The term is sometimes applied to other compounds having similar properties. -- Metallic phosphorus (Chem.), an allotropic modification of phosphorus, obtained as a gray metallic crystalline substance, having very inert chemical properties. It is obtained by heating ordinary phosphorus in a closed vessel at a high temperature. -- Phosphorus disease (Med.), a disease common among workers in phosphorus, giving rise to necrosis of the jawbone, and other symptoms. -- Red, or Amorphous, phosphorus (Chem.), an allotropic modification of phosphorus, obtained as a dark red powder by heating ordinary phosphorus in closed vessels. It is not poisonous, is not phosphorescent, and is only moderately active chemically. It is valuable as a chemical reagent, and is used in the composition of the friction surface on which safety matches are ignited. -- Solar phosphori (Chem.), phosphorescent substances which shine in the dark after exposure to the sunlight or other intense light.