Part 327

Church discipline is platformed in the Bible.

Milton.

Plat*hel"minth (?), n. (Zoˆl.) One of the Platyelminthes.

||Plat`hel*min"thes (?), n. pl. [NL.] (Zoˆl.) Same as Platyelminthes.

Plat"in (?), n. (Mach.) See Platen.

Plat"i*na (?), n. [Sp. or NL. See Platinum.] (Chem.) Platinum.

Platina mohr, platinum black. -- Platina yellow, a pigment prepared from platinum.

Plat"ing (?), n. 1. The art or process of covering anything with a plate or plates, or with metal, particularly of overlaying a base or dull metal with a thin plate of precious or bright metal, as by mechanical means or by electro-magnetic deposition.

2. A thin coating of metal laid upon another metal.

3. A coating or defensive armor of metal (usually steel) plates.

Pla*tin"ic (?), a. (Chem.) Of, pertaining to, or containing, platinum; -- used specifically to designate those compounds in which the element has a higher valence, as contrasted with the platinous compounds; as, platinic chloride (PtCl4).

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Plat`i*ni*chlo"ric (?), a. (Chem.) Of, pertaining to, or designating, an acid consisting of platinic chloride and hydrochloric acid, and obtained as a brownish red crystalline substance, called platinichloric, or chloroplatinic, acid.

Plat`i*nif"er*ous (?), a. [Platinum + -ferous.] Yielding platinum; as, platiniferous sand.

Plat`i*ni*rid"i*um (?), n. (Chem. & Min.) A natural alloy of platinum and iridium occurring in grayish metallic rounded or cubical grains with platinum.

Plat"i*nize (?), v. t. [imp. & p. p. Platinized (?); p. pr. & vb. n. Platinizing (?).] To cover or combine with platinum.

Plat`i*no*chlo"ric (?), a. (Chem.) Pertaining to, derived from, or designating, an acid consisting of platinous chloride and hydrochloric acid, called platinochloric, or chloroplatinous, acid.

Plat`i*no*chlo"ride (?), n. (Chem.) A double chloride of platinum and some other metal or radical; a salt of platinochloric acid.

Plat`i*no*cy*an"ic (?), a. (Chem.) Pertaining to, derived from, or designating, an acid compound of platinous cyanide and hydrocyanic acid. It is obtained as a cinnaber-red crystalline substance.

Plat`i*no*cy"a*nide (?), n. (Chem.) A double cyanide of platinum and some other metal or radical; a salt of platinocyanic acid.

Plat"i*node (?), n. [Platinum + Gr. &?; a way.] (Physics) A cathode. [R.]

Plat"i*noid (?), a. [Platinum + -oid.] Resembling platinum.

Plat"i*noid, n. (Chem.) An alloy of German silver containing tungsten; -- used for forming electrical resistance coils and standards.

Plat"i*no*type (?), n. [Platinum + -type.] (Photog.) 1. A permanent photographic picture or print in platinum black.

2. The process by which such pictures are produced.

Plat"i*nous (?), a. (Chem.) Of, pertaining to, or containing, platinum; -- used specifically to designate those compounds in which the element has a lower valence, as contrasted with the platinic compounds; as, platinous chloride (PtCl2).

Plat"i*num (?), n. [NL., fr. Sp. platina, from plata silver, LL. plata a thin plate of metal. See Plate, and cf. Platina.] (Chem.) A metallic element, intermediate in value between silver and gold, occurring native or alloyed with other metals, also as the platinum arsenide (sperrylite). It is heavy tin-white metal which is ductile and malleable, but very infusible, and characterized by its resistance to strong chemical reagents. It is used for crucibles, for stills for sulphuric acid, rarely for coin, and in the form of foil and wire for many purposes. Specific gravity 21.5. Atomic weight 194.3. Symbol Pt. Formerly called platina.

Platinum black (Chem.), a soft, dull black powder, consisting of finely divided metallic platinum obtained by reduction and precipitation from its solutions. It absorbs oxygen to a high degree, and is employed as an oxidizer. -- Platinum lamp (Elec.), a kind of incandescent lamp of which the luminous medium is platinum. See under Incandescent. -- Platinum metals (Chem.), the group of metallic elements which in their chemical and physical properties resemble platinum. These consist of the light platinum group, viz., rhodium, ruthenium, and palladium, whose specific gravities are about 12; and the heavy platinum group, viz., osmium, iridium, and platinum, whose specific gravities are over 21. -- Platinum sponge (Chem.), metallic platinum in a gray, porous, spongy form, obtained by reducing the double chloride of platinum and ammonium. It absorbs oxygen, hydrogen, and certain other gases, to a high degree, and is employed as an agent in oxidizing.