PLANE n.
An ideal surface, conceived as coinciding with, or containing, some designated astronomical line, circle, or other curve; as, the plane of an orbit; the plane of the ecliptic, or of the equator.
PLATINUM n.
ng 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 pla…
PRIMITIVE a.
ve plane (Spherical Projection), the plane upon which the projections are made, generally coinciding with some principal circle of the sphere, as the equator or a meridian. -- Primitive rocks (Geol.), primary rocks. See under Primary. -- Primitive sheath. (Anat.) See Neurilemma. -- Primitive streak or trace (Anat.),…