magnetic 
field, the Ppace through which the force or Influence of a 
magnet is exerted ; also, tin spun- :. limit ;i com In* tor carry- 
ing "'i ' Ircd ir 'iii'MliI in u hirli, us it may hr shown, iniiL' 
netie force is also exert n I. Compare m<r </'"''''<' */,/'// (In li.\\ , 
ami .'//"'//*!. Magnetic fluid, :ihypothetical(1iiid the 
>'\isii'Mrrof irhlohwMaMUined In order to explain the phe- 
nomena of magnetism. Magnetic force, the force ex- 
erted brtwcen two magnets, or, more definitely, between 
two magnetic poles. It in repulsive hetween like and at* 
tractive between unlike poles, and varies in intensity 
with the product of their strengths directly, and with tho 
square of the distai lt\\n-n them inversely. Mag- 
netic guard. Sec yuan/. - Magnetic Induction, the 
power which n magnet or a current uf electricity possesses 
Of netting temporary or pennant-nt magnet Usm in such 
bodies in Us vicinity as are capahlc of receiving it. Sec 
intluctitm. d. Magnetic-induction capacity, same as 
magnetic jx'nueabuity. Magnetic intensity. Same as 
mtffMtte force. Magnetic limit, the temperature be- 
yond which a magnetic metal ceases to be affected by the 
magnet. For iron this is the temperature of bright-red 
heat ; for cobalt it is above that of white heat ; for nickel 
itisiiboutSiio c. Magnetic magazine, same aa mag* 
ii- (,'<!>,, ft. fit. Magnetic matter, an imaginary Hiiiistimr,' 
possessing magnetic properties, the distribution of which 
in a magnet is conceived t>y Sir William Thomson to repre- 
sent magnetic polarity. 
It will very often be convenient to refer the phenomena 
of magnetic force to attractions or repulsions mutually 
exerted between portions of an imaginary magnetic matter, 
which, as we shall see, may be conceived to represent the 
polarity of a magnet of any kind. 
Sir W. Thomson, Elect and Mag., p. 361. 
Magnetic meridian, moment, etc. See the nouns. 
Magnetic needle, anv small magnetized iron or steel rod 
turning on a pivot, such as the needle of the mariners' com- 
pass. Magnetic north, that point of the horizon which 
is indicated by the direction of the magnetic needle. It 
is seldom the true north. See magnetic meridian. Mag- 
netic Observatory, a station provided with apparatus 
for making both absolute and differential determinations 
of the elements of the earth's magnetism, and at which 
systematic observations are maintained. The instruments 
used for absolute measures are the magnetometer for the 
declination and horizontal force, and the dip-circle for the 
inclination. The instrument* used for differential mea- 
sures are the declinometer, which shows the changea in 
the declination, and magnetometers, which register the 
variations in the horizontal and vertical components of the 
force. By the application of photography a continuous 
registration of these variations is obtained. Magnetic 
permeability. See i>ermeability. Magnetic points of 
. 
convergence, the magnetic poles of the earth, around 
which are drawn the Isogonic lines, or lines of equal decli- 
nation. Magnetic poles of the earth, two nearly oppo- 
site points on the earth's surface, where the dip of the nee- 
dle is 80. They are at a considerable distance from the 
geographical poles of the earth. Magnetic potential. 
See potential. - Magnetic pyrites, a bronze-yellow mag- 
netic iron sulphid, varying in composition from Fe7Sg to 
l'eio$i i. Also called mjrrhotUe. Magnetic resistance 
or reluctance. See the nouns. Magnetic retentive- 
ness. Same as coercive force. Magnetic rotation of 
currents, the dynamical effects, observed under suitable 
conditions, produced by a magnet in rotating a conductor 
carrying a current, or conversely of a stationary conductor 
traversed by a current in rotating a magnet. Magnetic 
rotatory power, the rotation of the plane of polariza- 
tion of a ray of light passing through a transparent me- 
dium in a powerful magnetic field. According to the di- 
rection of rotation, it is designated as -f- or . Verdet's 
constant for a given substance is tho amount of rotation 
between two points whose difference of magnetic poten- 
tial is 1 c. g. s. unit. Sec polarization. Magnetic scale, 
a table or diagram exhibiting the paramagnetic and dia- 
magnotic metals in the order of their strengths. Mag- 
netic screen, a soft Iron shell for example, in the form 
of a sphere which, If of the proper thickness, cuts off a 
magnetic needle within from the effect of a magnet with- 
out. Such a screen is sometimes used to free a needle from 
the earth's force, so that it can obey the impulse of a cur- 
rent sent about it. Magnetic sense, a supposed special 
sense by which magnetic influences are perceived. 
Neither in my own case, nor in several others who tried, 
was anything felt that could be attributed to a magnetic 
KI'/IW. Proe. Sac. Psych. Research, II. 58. 
Magnetic separator, an apparatus or instrument for 
separating iron from other substances, as Iron from brass- 
fUings, or scraps of nails or wire from wheat. E. H. 
Knight. Magnetic shell, a magnet in the form of a very 
thin plate or sheet, the surfaces of which have opposite 
polarity. A thin slice off a cylindrical bar-magnet would be 
a magnetic shell ; or, in other words, a bar-magnet may he 
thought of as made up of a great number of magnetic shells 
placed together with their poles facing in the same direc- 
tion. A closed electric circuit for example, a circular 
wire traversed by a current is equivalent to a magnet- 
ic shell ; and a series of such circuits, or practically a sole- 
noid, has all the properties of a liar-magnet, and is sur- 
rounded by a similar Held of force. Magnetic Storm, 
an abrupt disturbance of the equilibrium of the magnetic 
forces controlling a freely suspended magnetic needle, 
which is thereby thrown into rapid oscillation and dis- 
placed from its mean position : usually observed simul- 
taneously over a considerable portion of the earth, and 
hence inferred by some to be of eosmical origin. Magnetic 
storms are often accompanied by electrical earth-currents, 
observed, for example, as a disturbing element in connec- 
tion with telegrapn-lines. They are most frequent dur- 
ing those periods(at intervals of about eleven years) when 
auroras are common, and both phenomena ac ompany the 
time of sun-spot frequency. Magnetic substance. See 
maynet. Magnetic susceptibility. See xum-ptiNKti/. 
-Magnetic telegraph, the electric telegraph. See 
telegraph. Magnetic tick, a faint metallic sound pro- 
duced when an iron bar is rapidly magnetized or de- 
magnetized. 
When an iron or cobalt bar is magnetized it becomes 
longer and somewhat more slender, but does not appre- 
ciably alter in volume, it also emits :i slight sound a 
'!' lick: A. Daiiii'll. 1'rin. of 1'hysics, p. 609. 
3576 
Magnetic unit. See imii. Point of magnetic indif- 
ference, that point of a magnet, about mi'l 
the t\vo extremes, where the attlaetive Inree, alter r,.||- 
tlnually diminishing as one proceeds from either pole, 
ceases altogether ; the equator of the magnet. 
II. n. 1. Any ini'tal, as iron, steel, nickel. 
cobalt, etc., which may receive the properties 
of tho lodestone. 2. A paramagnetic body, 
or ono which, when free to turn in a magnetic 
field, sets its longest axis along the lines of 
magnetic force : in contradistinction to diamatj- 
ii< in-. See diamaijix-tism. 
magnetical (mag-net'i-kal), a. and n. [< /</- 
iii-tii- + -/.] I. a. 1. Same as magnetic. 2. 
Exhaling or drawing out. 
There is an opinion, that the moon Is matrtietical of heat, 
as the sun Is of cold and moisture, llaron. Nat. Hist, , ) 75. 
Magnetical amplitude. See amplitude. 
ll.t A substance that baa magnetic prop- 
er! ics; a magnetic. 
Men that ascribe thus much unto rocks of the Sort h 
must presume or discover the like inayneticals In the 
South. For, In the Southern Seas and far beyond the 
Equator, variations are large, and declinations as constant 
as In the Northern Ocean. Sir T. Browne, Vulg. Err., II. . 
magnetically (mag-net'i-kal-i), adv. In a mag- 
netic manner; by magnetism. 
magneticalness (mag-net'i-kal-nes), . The 
property of being magnetic, ffiftt. Kay. Soc., 
IV. 253. 
magnetician (mag-ne-tish'an), H. [< magnetic + 
-iim.\ One skilled in magnetism ; amagnetigt. 
magneticness (mag-net'ik-nes), ti. The qual- 
ity of being magnetic ; magneticalness. 
magnetics Ymag-net'iks), n. [PI. of magnetic: 
see -ics.] The science or principles of magnet- 
ism. 
magnetine (mag'ne-tin), . [< magnet + -i2.] 
1. The principle of magnetism ; a hypothetical 
imponderable matter in which magnetic phe- 
nomena are supposed to occur. Compare fa- 
mine. 
It Is upon their operation, but more particularly on the 
Influence of magnet\ne, that the vital functions In all their 
modifications are dependent. 
Athburner, in Reichenbach's Dynam!cs(trans. 1851), p. xlv. 
2. A compound of some kind of cementing 
material and a magnetic powder, such as iron- 
filings or magnetic oxid of iron, used in some 
forms of magnetic belts, etc. 
magnetipolar (mag'net-i-po'lar), a. [< L. mag- 
ncs (magnet-), magnet, + polus"pol& : see polar.] 
Possessing magnetic polarity : as, platinum is 
sometimes magnetipolar. 
magnetisability, magnetisable, etc. See mag- 
netizabilily, etc. 
magnetism (mag'ne-tizm), n. [= F. magne- 
tixme = Sp. Pg. It. magnetismo = D. magnc- 
tisme = G. iiitii/iirtif HI n* = Dan. magnetisme = 
Sw. magnetism, < NL. magnetismvs (NGr. //oj- 
v>jTio/i6f), < L. magnes (magnet-), a magnet: see 
magnet and 4m.] 1. That peculiar property 
occasionally possessed by certain bodies (more 
especially by iron and steel) whereby, under 
certain circumstances, they naturally attract 
or repel one another according to determinate 
laws. According to the molecular theory of magnetism, 
the molecules of a magnetic substance possess permanent 
polarity, and as It is more and more highly magnetized the 
poles are arranged more and more perfectly in a common 
direction ; when It is magnetized to the highest degree pos- 
sible that is, to saturation all the north poles of the 
molecule* point In one direction and all the south poles 
In the opposite direction. On this theory coercive force is 
simply that condition of the substance which retards this 
molecular arrangement during the process of magneti- 
zation and tends to retain it after magnetization. The 
current theory,or Ampere's theory of magnetism, supposes 
each molecule to be traversed by a closed electric circuit ; 
these currents become parallel upon magnetization, and 
may then be regarded as equivalent to a series of closed 
eleetric currents about the exterior of the bar, these cur- 
rents being clockwise at the south pole and counter-clock- 
wise at the north pole. This theory derives its support 
from the observed fact that a spiral conductor traversed 
by a current (a solenoid) behaves as a magnet In all re- 
spects, being directed similarly by the earth and having 
a similar field of force about It. See magnet. 
In many treatises it is the fashion to speak of a mag- 
netic fluid or fluids; it is, however, absolutely certain 
that maynetitm is not a fluid. . . . A fluid cannot possibly 
propagate itself indefinitely without loss. 
5. P. Thompson, Elect, and Mag., p. 81. 
2. That branch of science which treats of the 
properties of the magnet, and of magnetic phe- 
nomena in general. 3. Attractive power; ca- 
pacity for exciting sympathetic interest or at- 
tention: as, the iinii/iii-tixm of eloquence ; per- 
sonal IHIII/III ti.ini. 
I do not think he [Dryden] added a single word to the 
language, unless, as I suspect, he first used maynrtimt in 
its present sense of moral attraction. 
Linirll. Among my Books, 1st ser.. p. 70. 
Animal magnetism, the name given by Mcsmcr t" th 
phenomena of mesmerism. <rr ,,i,yi,i.'n>m ami 
magneto-electric 
Km Blue magnetism, that of the south pole of mag- 
net. Diffusion of magnetism, see <tiffunn. in- 
duced magnetism. B Lamellar mag- 
netism, magnetism distributed ter a surface, as of a 
magnetic -hi II in distinction from i onom 
trated at a point, as at a i-le. Red magnetism, that 
of the north pole of a magnet.- Residual magnetism, 
the magnetism remain ing in a mass nf iron alter the mag- 
netizing Influences have heen removed. Its amount in- 
creases with the coercive force and the thhincM of the 
bars, ami in perfectly pure soft iron is practical!) /ein 
for bars of moderate thickness In comparison with thut 
length. Retentive magnetism, permanent magnet- 
Isin, as of an iron ship. Terrestrial magnetism, the 
magnetic properties possessed by the earth as a whole, 
which give the needle Its directive power and cause It to 
dip, and which also communicate magnetism by Induction, 
as to a bar of iron placed parallel to the dipping-needle. 
See declination, dip; also aclinic, isoclinal, \9ogonic* . 
magnetist (mag'ne-tist), n. [< magnet + -ixt.'] 
One who is versed in the science of magnetism ; 
a magnetician. 
magnetite (mag'ne-tit), H. [< magnet + -fe2.] 
Magnetic oxid of iron; a black oxid of iron 
(Fe 3 C>4 or FeO.Fe 2 O 3 ) which is strongly at- 
tractable by a magnet. It sometimes possesses po- 
larity, and Is then called lodeitane. It occurs In isometric 
crystals, generally octahedrons or dodecahedrons, and 
also more commonly massive in beds In the older crystal- 
line rocks ; in the form of scattered grains or crystals It 
Is a common constituent of many igneous rocks. It is an 
important ore of iron, and occurs in large quantities in 
Norway and Sweden, in the Adirondack and West Point 
regions of New York, and in New Jersey. Titanlferous 
magnetite is a variety containing some titanium. 
magnetitic (mag-ne-tit'ik), a. [< magnetite + 
-tclj Pertaining to magnetite; of the nature 
of magnetite ; containing magnetite : as, mag- 
netitic slates. 
magnetizability (mag-ne-ti-za-bil'j-ti), n. [< 
magnetizable : see -bility."] The power or sus- 
ceptibility of being magnetized ; the coefficient 
of magnetic induction. To Increase the magnetiza- 
bility Is to Increase the coefficient of magnetic Induction ; 
to load with magnetizability is to load with magnetic in- 
duction. Also spelled mai/netimltiiity. 
magnetizable (mag'ne-ti-za-bl), a. [< magnetize 
+ -able.'] Capable of being magnetized. Also 
spelled magnetisable. 
magnetization (mag'ne-ti-za'shon), n. f< mag- 
netize + -ation.] The act of magnetizing, or 
the state of being magnetized. A 1-n spelled 
</Hf</.<!flftM.-Magnetlzatlon of light, a phrase 
used by Faraday to express the mutual relation which he 
proved to exist between magnetism and light. He ap- 
plied It especially to the phenomenon of the rotation of 
the plane of polarization of a light-ray passed through a 
transparent medium in a powerful magnetic Held. 
magnetize (mag'ne-tiz), c. ; pret. and pp. mag- 
netized, ppr. magnetizing. [= D. magnetixeren 
= G. magnetisiren = Dan. magnetiserc = 8w. 
magnetisera = F. magnetiser = Sp. magnetizar 
= Pg. magnctisar = It. magnetizsare ; as magnet 
+ -ize.~\ I, trans. 1. To communicate mag- 
netic properties to: as, to magnetize a needle. 
2. To attract as if by a magnet ; move ; in- 
fluence. 3. To put under the influence of ani- 
mal magnetism : mesmerize ; hypnotize. 
II. intrans. To acquire magnetic properties ; 
become magnetic: as, a bar of iron standing 
some time in an inclined position will mag- 
netize. 
Also spelled magnetise. 
magnetizee (mag'ne-ti-ze'), . [< magnetize + 
-Ms] One who is magnetized or mesmerized. 
Also spelled magnetisee. 
magnetizer (mag'ne-ti-zer), . 1. That which 
communicates magnetism. 2. One who mag- 
netizes or mesmerizes. 
Also spelled magnetiser. 
magneto (mag'ne-to), n. [Short for magneto- 
ili-i-trii-iil MOoNM.] A magneto-electric ma- 
chine : as, a magneto-motor. S. /'. Thompson, 
Dynamo-Elect. Mach., p. 368. 
magneto-. A combining form of magnet or mag- 
iii'tii; often implying especially magiieto-elertric. 
As applied to electric machines, it is used (in contradis- 
tinction to dynamo-) to indicate that the magnetic fields 
involved are due to permanent magnets. 
magneto-bell (mag'ne-to-bel). n. An electric 
bell in which the armature of the electromagnet 
is polarized that is, is a permanent magnet. 
The armature is alternately attracted and repelled when 
the alternate cnrrcnt from a magneto-electric machine Is 
passed through the coll of the electromagnet, and a ham- 
mer attached to a continuation of the armature placed 
between two bells rings them. It is used as a telephone 
call-bell. Also called magneto cailbeil. 
magnetod (mag'ne-tdd), H. [< magnet + </.] 
MiiKnetine; magnetic od; the hypothetical odic 
force or principle of magnetism. Rcichcnback. 
magneto-electric (mag*ne-t6-e-lek'trik), a. 
Pertaining to magneto-electricity. See elec- 
fromv<'<''*'<^-aiaract*risttc of a magneto-elec- 
tric machine, see characteristic, Magneto-electric 
induction, n-e induction, 6. Magneto-electric ma- 
chine. Sec .1,,'lr;,- inacliiii'-, under rlrctric. Magneto- 
