Iron.
A metal; one of the elements; symbol, Fe; atomic weight, 56;
equivalent, 28 and 14, ; valency, 4 and 2.
It is a conductor of electricity. The following data are at
0° C. 32° F., with annealed metal.
Specific Resistance, 9.716 microhms.
Relative Resistance. 6.460
Resistance of a wire,
(a) 1 foot long weighing 1 grain, 1.085 ohms.
(b) 1 foot long 1/1000 inch thick, 58.45 "
(c) 1 meter long weighing 1 gram, .7570 "
(d) 1 meter long, 1 millimeter thick, .1237 "
Percentage increase in resistance per degree C. (1.8° F.)
at about 20° C. (68°F.), about 0.5 per cent.
Resistance of a 1 inch cube, 3.825 microhms.
Electro-chemical equivalent (Hydrogen = .0105), .147 and .294
Iron, Electrolytic.
Iron deposited by electrolytic action. Various baths are employed for
its formation. (See Steeling.) It has very low coercive power, only
seven to ten times that of nickel.
Ironwork Fault of a Dynamo.
A short circuiting of a dynamo by, or any connection of its coils with,
the iron magnet cores or other iron parts.
Isochronism.
Equality of periodic time; as of the times of successive beats of a
tuning fork, or of the times of oscillations of a pendulum.
Isoclinic Lines.
The lines denoting the locus of sets of equal dips or inclinations of
the magnetic needle upon the earth's surface, the magnetic parallels, q.
v. These lines are very irregular. (See Magnetic Elements.)
Isoclinic Map.
A map showing the position of isoclinic lines.
Isodynamic Lines.
Lines marking the locus of places of equal magnetic intensity on the
earth's surface. (See Magnetic Elements, Poles of Intensity.)
Isodynamic Map.
A map showing the position of isodynamic lines. (See Poles of
Intensity.)
Isogonic Lines.
Lines on a map marking the locus of or connecting those points where the
declination or variation of the magnetic needle is the same. (See
Magnetic Elements--Declination of Magnetic Needle.)
Synonyms--Isogonal Lines--Halleyan Lines.