(Phos*phor"o*scope) n. [Phosphorus + -scope.] (Physics) An apparatus for observing
the phosphorescence produced in different bodies by the action of light, and for measuring its duration.
(Phos"phor*ous) a. [Cf. F. phosphoreux.] (Chem.) Of or pertaining to phosphorus; resembling
or containing phosphorus; specifically, designating those compounds in which phosphorus has a lower
valence as contrasted with phosphoric compounds; as, phosphorous acid, H3PO3.
(Phos"phor*us) n.; pl. Phosphori [L., the morning star, Gr. lit., light bringer; light + to
1. The morning star; Phosphor.
2. (Chem.) A poisonous nonmetallic element of the nitrogen group, obtained as a white, or yellowish,
translucent waxy substance, having a characteristic disagreeable smell. It is very active chemically, must
be preserved under water, and unites with oxygen even at ordinary temperatures, giving a faint glow,
whence its name. It always occurs compined, usually in phosphates, as in the mineral apatite, in
bones, etc. It is used in the composition on the tips of friction matches, and for many other purposes.
The molecule contains four atoms. Symbol P. Atomic weight 31.0.
3. (Chem.) Hence, any substance which shines in the dark like phosphorus, as certain phosphorescent
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.
(Phos"phor*yl) n. [Phosphorus + -yl.] (Chem.) The radical PO, regarded as the typical
nucleus of certain compounds.
(Phos"phu*ret) n. (Chem.) A phosphide. [Obsoles.]
Phosphureted hydrogen. (Chem.) See Phosphine.
(Phos"phu*ret`ed) a. (Chem.) Impregnated, or combined, with phosphorus. [Obsoles.]
[Written also phosphuretted.]
(Pho"tic) a. [Gr. fw^s, fwto`s, light.] (Physiol.) Relating to the production of light by the lower
(Pho"tics) n. (Physics) The science of light; a general term sometimes employed when optics
is restricted to light as a producing vision. Knight.