PALLADIUM n.
t does to the extent of nearly a thousand volumes, forming the alloy Pd2H. It is used for graduated circles and verniers, for plating certain silver goods, and somewhat in dentistry. It was so named in 1804 by Wollaston from the asteroid Pallas, which was discovered in 1802. Symbol Pd. Atomic weight, 106.2.…
PIANO; PIANOFORTE n.
al instrument somewhat resembling the harpsichord, and consisting of a sreies of wires of graduated length, thickness, and tension, struck by hammers moved by keys. Dumb piano. See Digitorium. -- Grand piano. See under Grand. -- Square piano, one with a horizontal frame and an oblong case. -- Upright piano, one with…
QUADRANT n.
different specific uses in astronomy, surveying, gunnery, etc., consisting commonly of a graduated arc of 90º, with an index or vernier, and either plain or telescopic sights, and usually having a plumb line or spirit level for fixing the vertical or horizontal direction. Gunner's quadrant, an instrument consisting of…
REFRACTION n.
refraction. See under Index. -- Refraction circle (Opt.), an instrument provided with a graduated circle for the measurement of refraction. -- Refraction of latitude, longitude, declination, right ascension, etc., the change in the apparent latitude, longitude, etc., of a heavenly body, due to the effect of atmosphe…
REPEATING a.
everal times in succession, and different, but successive and contiguous, portions of the graduated limb, before reading off the aggregate result, which aggregate, divided by the number of measurements, gives the angle, freed in a measure from errors of eccentricity and graduation. -- Repeating watch. See Repeater (a)…
RULE n.
A measuring instrument consisting of a graduated bar of wood, ivory, metal, or the like, which is usually marked so as to show inches and fractions of an inch, and jointed so that it may be folded compactly. A judicious artist will use his eye, but he will trust only to his rule. South.