electromagnet 
1870 
electrophysiology 
of soft iron and a current of electricity is passed through alx>ve or within this, if the cylindrical form is used, a Hat electlO-OPtiCS (e - lek-tro - op ' tiks), n. That 
.ryniagnetwithanorthand n.cdie of ium^hun ^"^ire^ Th br aneh of tl.e science of electricity which treats 
nectinn usually with a Leyden jar placed above or below Ot relations to lignt. Among these relations are : 
and if the two pairs of quadrants are dissimilarly electri- the production of double refraction, as in glass, by the 
fled that Is, are in a state of different potential, as by electrostatic stress produced when two wires from an - 
a south pole ; the end at which the current circulates 
through the wire in the direction of the hands of a clock, 
as the observer looks at it, is the south pole. In practice, 
an electromagnet has ordinarily a horseshoe form. It 
consists of two cylinders, or cores, of soft iron, fastened 
together at one end and each wound many times with in- 
sulated wire ; the wire must be so wound that if the horse- 
shoe were straightened the direction of winding would be 
the same throughout. An electromagnet may be made 
very powerful, so as to support a ton or more. The soft 
iron core retains its maximum magnetization only so long 
as the current is passing, and loses nearly all of it the in- 
stant the current ceases. This principle is made use of 
in the telegraph (which see), electric clocks, electric call- 
bells, etc. If the core is made of steel, it becomes under 
the action of the current a permanent magnet. 
electromagnetic (e-lek"tro-mag-net'ik), a. 
connecting them respectively with the poles of a voltaic 
cell the needle is deflected from its position of rest, and 
the amount of this deflection, as measured by the motion 
of a spot of light reflected from a small mirror attached 
to it, gives a means of calculating the difference of poten- 
tial of the bodies under experiment. In another method 
of using the quadrant electrometer the pairs of quadrants 
are kept at a constant difference of potential, while that 
of the needle varies. Arranged in this manner, it is much 
used in the investigation of atmospheric electricity. Lipp- 
mann and Dewar have devised very delicate capillary 
ctric action. 
duction coil or Holtz machine are fixed iu holes in it near 
together; the rotation of the plane of polarization of a ray 
of light on traversing a transparent medium placed iu 
a magnetic field, or by reflection at the surface of a mag- 
net ; the change of electrical resistance exhibited by cer- 
tain bodies during exposure to light, as selenium (see pha- 
tophotie) ; and the relation between the index of refraction 
and the specific inductive capacity of transparent bodies 
which is established by experiment and required by the 
electromagnetic theory of light. 
i-lek-tro-path'ik), a. [< elec- 
Pertaiuing to electropathy. 
. 274, adv. p. iii. 
Pertaining to electromagnetics, or to the rela- electrometric, electrometrical (e-lek-tro- -ff'll^' fit' ^- ; 7 2 ,' ft, -\ r , r -, 
tion between electricity and magnetism; of the met'rik, -ri-kal), . [As electrometer + -ic, electropathy (e-lek-trop a-thi) . [< Gr. <?/U*- 
nature of electromagnetism. See electromag- -icaZ.] Of or pertaining to electrometry, or T f*%> a . mber < r f e P r ' electricity), + -naffeia,< jrafof, 
netism. Alsoffafe.owomamjefe.-Electromaenetlc the measurement of electricity : as. an electro- suffering Cf. homeopathy 1 Treatment of dis- 
the measurement of electricity : as, an electro- 
metrical experiment. 
ease by electricity ; electrotherapeutics. 
,, ,, v +wm ,/., + _ n . rAc .,. electrophone (e-lek'tro-fon). n. [< Gr. //Am-ow, 
(e-Jek-trom e-tn), n. |As i elee- a mber?rer>r pip^fricifvl + L >v i, vni nnnd T 
science ' eri.repr.ei city;, f puvy, voice, sound.J 
S? instrument lor producing sounds, resem- 
Also galvanotnagnetic. Electromagnetic 
engine, machine. See electric machine, under electric. 
Electromagnetic theory of light. See %A(. Elec- 
tromagnetic units, units employed in measuring electric - . 
currents, and based upon the force exerted between two trometer + -y,\ That department of the science 
magnetic poles; the units practically used to measure the of electricity which embraces the methods of ,,. , . . - , 
strength of currents (ampere), electromotive force (volt), making plpctrical mpnsni-pmpnts morn pnp Wing trumpet-tones, by electric currents of high 
resistance (ohm) etc., are electromagnetic units. "ally of stat clTeletricU? P tension ' " as be recommended for use as a tele- 
electromagnetically (e-lek"tro-mag-net'i- """y - uy -, , , , ->. ' - ,.....:...- , ,. 
kal-i), adv. In an electromagnetic manner; by electromotion (e-lek-tro-mo'shon), n. 1. The 
electromagnetism current of electricity, or the passing of it from 
one metal to another, in a voltaic circuit. 2. 
Mechanical motion produced by means of elec- 
tricity. 
A single wire bent twice at right-angles is made to ro- 
tate electro-magnetically between the poles of a horseshoe 
magnet. Dredge's Electric Illumination, I. 74. 
graphic relay capable of giving two or four signs with 
a single wire, having this advantage over other relays, 
that perfection. of contact is not necessary to its working. 
It has been used also to indicate the electric equilibrium 
of muscle and nervous tissue by the variation of its tones, 
and by a system of levers attached to the wrist to show 
the rhythm and character of the pulse ; and it may be 
electromagnetics (e-lek"tro-mag-net'iks) n electromotive (e-lek-tro-mo'tiv), a. Oforper- fitted to the telephone, and thus be made to repeat a sound 
tinin - """le gently in one lace in trumet-tones in another lace 
The science of electromagnetism. 
(e-lek-tro-mag'net-izm), n. 
taining to electromotion ; producing or pro- 
duced by electromotion Electromotive force 
made gently in one place in trumpet-tones in another place 
hundreds of yards distant. Chambers'^ Encyc. 
magnetism in a magnetic substance, as soft iron, and also 
the analogous effects of a magnet in directing a movable 
conductor traversed by a current, or in inducing in a con- 
ductor an electric current. The directive power of an 
electric current upon a magnet was discovered by Oer- 
sted ; it is the principle involved in all forms of galvanom- 
eter (which see). The power of an electric current to 
induce magnetism, and of a magnet to induce an electric 
current, is treated under induction; these latter phenom- 
, , .. [NL., 
similar relation to it that the pressure in a Water-pipe does < Alectrophorus + -idtr.'] A family of anguilli- 
to the difference of water-level upon which its amount form fishes, of the order Plectosponduli. There 
depend Ihe strength of an electric current is directly are no scales nor dorsal flu ; the head is rounded in front, 
.opoitiona to the electromotive force, and inversely the premaxillaries forming most of the upper border of 
proportional to the resistance (Ohms law). Ihe elec- the mouth, and the supramaxillaries being reduced ; and 
" ' ' " * 
. 
tromotive force is measured in volts. Electromotive 
series, the series of the various metals (or other sub- 
stances) useful for producing an electric current, ar- 
- _____________ , ....... _____ r __________ ranged in such an order for a given liquid that each is .... 
ena form the basis of the electromagnet and of all forms positive with reference to those which follow in the list, -i--* -u j /- i t- j_ t/- j\ 
of magneto-electric and dynamo-electric machines and negative for those which precede. For example, in el eCTirOpnOrOia (e-lek-trol O-roid), a. and n. 
liilute sulphuric acid the order is zinc, lead, iron, cop- " D ^" : ---- * --- ' --- : "-- - 1 - ---- " ---- * 
per ' Si 8 "'a"""?', carbon -that is, if zinc and iron are 
- 
Clectromagnetist (e-lek-tro-mag'net-ist) n 
One skilled in electromagnetism. 
electromassage (e-lek"!r6-ma- sa zh'), B . In 
therap., the combination of the use of electri- 
city with massage by employing the more or 'he current in the wire is from copper to iron. It is found 
less seciall modified electrod 
the anus is under the throat, the anal flu beginning just 
behind it, and continuous with the caudal. The family 
contains the electric eel (which see, under eel). See also 
GymnotUlfe. 
a. Pertaining to or having the characters of the 
Electrophoridce. 
II. n. One of the Electrophoridcu. 
the wire from iron to zinc; if iron and cop"peraretakeii' ClectrOphorOUS (e-lek-trof'o-rus), a. [< NL. 
electrophorus : see electrophorm.] Sameasetec- 
less specially modified electrodes of a galvanic caroon anaisenui f 
or faradic battery as instruments for more or for all the intervening metals. In another liquid the orde? electrophOTOS (e-lek-trof'o-rus), n. [= F. elec- 
tropJiore = Sp. electroforo, < NL. eleetrophorus, 
< Gr. i/teKrpov, amber (repr. electricity), + 
conductor by having "its surface brushed"over with electromotor (f-lek-tro-mo'tor), n. [= .6lee- 
powdered graphite. It is then attached to the negative tromoteur = Sp. electromotor ; < L. electrum, son- 
pole of the battery and suspended in the solution of the ber (repr. electricity), + motor, a mover 1 1 
WarLigement /4h gives rise to anllecl 
The result of the 
the passage of the 
nsistiug of a plate of the same n t 1 J - 11 "' u 6u- zui, wiiicn gives rise to an eiec- 
electrolysis (see electrolysis) caused by tr * c current, as a single cell, a voltaic battery, 
j current is the decomposition of the so- or a thermo-electric pile. 2. An engine in 
lution the metal being deposited upon the exposed sur- which electricity is employed to produce me- 
SSSBflSft'lSrSS^SiiSfe C , hanical e F 6Cts See -under 
of the copperplate, and thus keens the solution of con- electric, and motor. 
stant strength. A current of uniform strength is neces- electromuSCUlar (e-lek-tro-mus'ku-lar), a. 
S aSttff JSAgStfa'aSSaS Pertaining to the relations between electricity 
alkaline solutions containing potassium cyanide and oertam phenomena exhibited by muscles. 
electrometer (e-lek-trom'e-ter), n. [= D. G. electron (e-lek'tron), n. Same as electrum. 
less imperfect rubbing and kneading. would be changed, but the above law would hold true"; for 
electromedical (e-lek-tro-med'i-kal) a Per- exan 'P le > '" potassium sulphid, iron is electro-negative 
taining to the medicinal use of electricity. with reference to copper. Also called contact series. ^ npof> < ^peiv = E. ftertfl'.] * 1. PI. electronhori 
electrometallurgy (e-lek-tro-met'al-er-ji) eiectromotograpn (e-lek-tro-mo'to-graf), n. (-ri). An instrument for obtaining statical 
The art of depositing certain metals, as gold A name sometimes applied to a peculiar tele- electricity by means of induction, it consists of 
silver, copper, etc., from their solutions bv Phone-receiver invented by Edison. The vibra- a disk of resin, or other non-conducting material easily 
means of the slow action of nn plpptrir. nnm-ont ms ' the mk ' a disk '^ whicn tlle 8 " und is reproduced excited by friction, and a polished metal disk with an 
irrent. are caused bv variations in frirfi,,ni ri a t.,^,. hof..^ insulating handle. The resin disk is negatively electri- 
fied by striking or rubbing it with 
a catskin or flannel, and the metal 
plate is then laid upon it Under 
these circumstances the upper plate 
does not receive a direct charge 
from the lower, but is positively 
charged on the lower surface and 
negatively on the upper ; if now the 
disk is touched by the finger, the 
negative electricity passes to the Voita's Electrophorus. 
ground, leaving the disk charged 
positively. On being lifted away by its insulating handle, 
it is found to be charged, and will give a spark. It may 
then be replaced on the lower plate, and the process re- 
peated an indefinite number of times without any fresh 
excitation, if the weather is favorable. The electricity 
obtained each time is the equivalent of the mechanical 
work done in separating the two surfaces against the at- 
traction of the unlike electricities. 
2. [cap.] [NL.] The typieal genus of Elec- 
Dan. Sw. electrometer "= F. 7lectromeire ='&n electronegative (e-lek-tro-neg'a-tivj, a. and w. <r oP 7 ">nW<B. There is but one species, the elee- 
electr6metro = Pg.electrometro=It.elettrometro * " 1 - Repelled by bodies negatively electri- trie eel, . e/ecncs. Gill, 1864. See cut un- 
< Gr. rfXuapov, amber (repr. electricity) + ut- fied > an( i attracted by those positively electri- , er * el - , 
rpov, a measure.] An instrument for measur- fied ! havin g a tendency to pass to the positive electropnotometer (e-lek^tro-fo-tom'e-ter), w. 
ing difference of electrostatic potential between P ole in electrolysis. 2. Assuming negative An instrument tor comparing the intensities of 
t J--_i-_ n ! *:! _.! __ i_ -i _Jil. . J- _?__,__ VarlOllS llffhts bv TPfprBTlPB tn t>!0 ITltoTloit^ ^f 
MDetween them heing known. Thejtiadronf p/ertruw- Q I Q + + - ,- , , . - ,..,. ' eieCtrOpHyslOlOgy (e-lek"tro-nz-l-oro-ji), n. 
eter of Sir William Thomson consists of four quadrant- electro-optic (e-lek-tro-op'tik), n. Of or per- That branch of science which treats' of elec- 
W^lft'^^^hSS^S^'^^ a a ction g <0 electr -P tics: as ' an 'tetrooptic trie phenomena produced through physiological 
agonc'ies. 
