I*som"er*ism (?), n. (Chem.) The state, quality, or relation, of two or
more isomeric substances.
Physical isomerism (Chem.), the condition or relation of certain
(metameric) substances, which, while chemically identical (in that they
have the same composition, the same molecular weights, and the same
ultimate constitution), are yet physically different, as in their
action on polarized light, as dextro- and lævo-tartaric acids. In such
compounds there is usually at least one unsymmetrical carbon atom. See
Unsymmetrical.
I`so*mer`o*mor"phism (?), n. [Isomer + Gr. &?; form + -ism.]
(Crystallog.) Isomorphism between substances that are isomeric.
{ I`so*met"ric (?), I`so*met"ric*al (?), } a. [Iso- + Gr. me`tron
measure.] 1. Pertaining to, or characterized by, equality of measure.
2. (Crystallog.) Noting, or conforming to, that system of
crystallization in which the three axes are of equal length and at
right angles to each other; monometric; regular; cubic. Cf.
Crystallization.
Isometric lines (Thermodynamics), lines representing in a diagram the
relations of pressure and temperature in a gas, when the volume remains
constant. -- Isometrical perspective. See under Perspective. --
Isometrical projection, a species of orthographic projection, in which
but a single plane of projection is used. It is so named from the fact
that the projections of three equal lines, parallel respectively to
three rectangular axes, are equal to one another. This kind of
projection is principally used in delineating buildings or machinery,
in which the principal lines are parallel to three rectangular axes,
and the principal planes are parallel to three rectangular planes
passing through the three axes.
I"so*morph (?), n. [See Isomorphous.] A substance which is similar to
another in crystalline form and composition.
I`so*mor"phic (?), a. Isomorphous.
I`so*mor"phism (?), n. [Cf. F. isomorphisme.] (Crystallog.) A
similarity of crystalline form between substances of similar
composition, as between the sulphates of barium (BaSO4) and strontium
(SrSO4). It is sometimes extended to include similarity of form between
substances of unlike composition, which is more properly called
homœomorphism.
I`so*mor"phous (?), a. [Iso- + -morphous.] Having the quality of
isomorphism.
||I`so*nan"dra (?), n. [Iso- + Gr. &?;, &?;, a man, male.] (Bot.) A
||genus of sapotaceous trees of India. Isonandra Gutta is the principal
||source of gutta-percha.
||
I`so*ne*phel"ic (?), a. [Iso- + Gr. &?; a cloud.] (Phys. Geog.) Having,
or indicating, an equal amount of cloudiness for a given period; as,
isonephelic regions; an isonephelic line.
I`so*nic"o*tine (?), n. [Iso- + nicotine.] (Chem.) A crystalline,
nitrogenous base, C10H14N2, isomeric with nicotine.
I`so*nic`o*tin"ic (?), a. (Chem.) (a) Pertaining to, or derived from,
isonicotine. (b) Pertaining to, or designating, an acid isomeric with
nicotinic acid.
I`so*ni*tro"so- (?). [Iso- + nitroso-.] (Chem.) A combining form (also
used adjectively), signifying: Pertaining to, or designating, the
characteristic, nitrogenous radical, NOH, called the isonitroso group.
I`so*nom"ic (?), a. [Gr. &?;; &?; equal + no`mos law.] The same, or
equal, in law or right; one in kind or origin; analogous; similar.
Dana.
I*son"o*my (?), n. [Gr. &?;: cf. F. isonomie. See Isonomic.] Equal law
or right; equal distribution of rights and privileges; similarity.
I*sop"a*thy (?), n. [Iso- + Gr. &?; suffering.] (Med.) (a) The system
which undertakes to cure a disease by means of the virus of the same
disease. (b) The theory of curing a diseased organ by eating the
analogous organ of a healthy animal. Mayne. (c) The doctrine that the
power of therapeutics is equal to that of the causes of disease.
I`so*pep"sin (?), n. [Iso- + pepsin.] (Physiol. Chem.) Pepsin modified
by exposure to a temperature of from 40° to 60° C.
I`so*per`i*met"ric*al (?), a. [Gr. &?;; &?; equal + &?; circumference:
cf. F. isopérimètre. See Perimeter.] (Geom.) Having equal perimeters of
circumferences; as, isoperimetrical figures or bodies.
I`so*per*im"e*try (?), n. (Geom.) The science of figures having equal
perimeters or boundaries.
I`so*pi*es"tic (?), a. [Iso- + Gr. &?; to press.] (Thermodynamics)
Having equal pressure.
Isopiestic lines, lines showing, in a diagram, the relations of
temperature and volume, when the elastic force is constant; -- called
also isobars.
||I`so*pleu"ra (?), n. pl. [NL. See Iso-, and Pleura.] (Zoöl.) A
||subclass of Gastropoda, in which the body is symmetrical, the right
||and left sides being equal.
||
The intestine terminates at the posterior end of the body, and the
gills and circulatory and reproductive organs are paired. It includes
the chitons (Polyplacophora), together with Neomenia and Chætoderma,
which are wormlike forms without a shell.
I"so*pod (?), a. (Zoöl.) Having the legs similar in structure;
belonging to the Isopoda. -- n. One of the Isopoda.
||I*sop"o*da (?), n. pl. [NL. See Iso-, and -poda.] (Zoöl.) An order of
||sessile-eyed Crustacea, usually having seven pairs of legs, which are
||all similar in structure.
||
The body is usually depressed, with the abdominal segments short, and
often consolidated in part. The branchiæ are on the abdominal
appendages. The group includes the terrestrial pill bugs and sow bugs,
with numerous marine forms. See Arthrostrata, Gribble.
I`so*pod"i*form (?), a. [Isopod + -form.] (Zoöl.) Having the shape of
an isopod; -- said of the larvæ of certain insects.
I*sop"o*dous (?), a. Same as Isopod.
I`so*pog"o*nous (?), a. [Iso- + Gr. &?; beard.] (Zoöl.) Having the two
webs equal in breadth; -- said of feathers.
I"so*prene (?), n. [Etymol. uncertain.] (Chem.) An oily, volatile
hydrocarbon, obtained by the distillation of caoutchouc or
gutta-percha.
I`so*pyc"nic (?), a. [Iso- + Gr. pykno`s dense.] (Physics) Having equal
density, as different regions of a medium; passing through points at
which the density is equal; as, an isopycnic line or surface.
I`so*pyc"nic, n. (Physics) A line or surface passing through those
points in a medium, at which the density is the same.
I*sor"cin (?), n. [Iso- + orcin.] (Chem.) A crystalline hydrocarbon
derivative, metameric with orcin, but produced artificially; -- called
also cresorcin.
I`sor*rop"ic (?), a. [Gr. 'iso`rropos in equipoise; 'i`sos equal +
"roph` downward inclination or momentum.] Of equal value.
Isorropic line (in a diagram) (Geom.), the locus of all the points for
which a specified function has a constant value. Newcomb.
I*sos"ce*les (?), a. [L., fr. Gr. &?;; 'i`sos equal + &?; leg.] (Geom.)
Having two legs or sides that are equal; -- said of a triangle.
||I`so*spon"dy*li (?), n. pl. [NL., fr. Gr. 'i`sos equal + &?;, &?;, a
||vertebra.] (Zoöl.) An extensive order of fishes, including the
||salmons, herrings, and many allied forms.
||
I`so*spon"dy*lous (?), a. (Zoöl.) Of or pertaining to the Isospondyli;
having the anterior vertebræ separate and normal.
I`so*spor"ic (?), a. [Iso- + Gr. &?; fruit.] (Bot.) Producing but one
kind of spore, as the ferns and Equiseta. Cf. Heterosporic.
I`so*stem"o*nous (?), a. [Iso- + Gr. sth`mwn thread.] (Bot.) Having
exactly as many stamens as petals.
I`so*stem"o*ny (?), n. (Bot.) The quality or state of being
isostemonous.
I`so*sul`pho*cy"a*nate (?), n. (Chem.) A salt of isosulphocyanic acid.
I`so*sul`pho*cy*an"ic (?), a. (Chem.) Pertaining to, or designating, an
acid, HNCS, isomeric with sulphocyanic acid.
I*soth"er*al (?), a. Having the nature of an isothere; indicating the
distribution of temperature by means of an isothere; as, an isotheral
chart or line.
I"so*there (?), n. [Iso- + Gr. &?; summer, &?; to heat.] (Phys. Geog.)
A line connecting points on the earth's surface having the same mean
summer temperature.
I"so*therm (?), n. [Iso- + Gr. &?; heat, fr. &?; hot.] (Phys. Geog.) A
line connecting or marking points on the earth's surface having the
same temperature. This may be the temperature for a given time of
observation, or the mean temperature for a year or other period. Also,
a similar line based on the distribution of temperature in the ocean.
I`so*ther"mal (?), a. [Cf. F. isotherme.] (a) Relating to equality of
temperature. (b) (Phys. Geog.) Having reference to the geographical
distribution of temperature, as exhibited by means of isotherms; as, an
isothermal line; an isothermal chart.
Isothermal line. (a) An isotherm. (b) A line drawn on a diagram of
energy such that its ordinates represent the pressures of a substance
corresponding to various volumes, while the absolute temperature is
maintained at a constant value. -- Isothermal zones, spaces on opposite
sides of the equator having the same mean temperature, and bounded by
corresponding isothermal lines.
I`so*ther"mo*bath (?), n. [Iso- + Gr. &?; hot + &?; depth.] (Phys.
Geog) A line drawn through points of equal temperature in a vertical
section of the ocean.
I`so*ther`mo*bath"ic (?), a. Of or pertaining to an isothermobath;
possessing or indicating equal temperatures in a vertical section, as
of the ocean.
I*soth`er*om"brose (?), n. [Iso- + Gr. qe`ros summer + 'o`mbros rain.]
(Phys. Geog) A line connecting or marking points on the earth's
surface, which have the same mean summer rainfall.
I`so*ton"ic (?), a. [Iso- + tonic.] Having or indicating, equal tones,
or tension.
Isotonic system (Mus.), a system consisting of intervals, in which each
concord is alike tempered, and in which there are twelve equal
semitones.
I`so*tri*mor"phic (?), a. Isotrimorphous.
I`so*tri*mor"phism (?), n. [Iso- + Gr. &?; thrice + &?; form.]
Isomorphism between the three forms, severally, of two trimorphous
substances.
I`so*tri*mor"phous (?), a. Having the quality of isotrimorphism;
isotrimorphic.
I`so*trop"ic (?), a. [Iso- + Gr. &?; a turning, fr. &?; to turn.]
(Physics) Having the same properties in all directions; specifically,
equally elastic in all directions.
I*sot"ro*pism (?), n. Isotropy.
I*sot"ro*pous (?), a. Isotropic.
I*sot"ro*py (?), n. (Physics) Uniformity of physical properties in all
directions in a body; absence of all kinds of polarity; specifically,
equal elasticity in all directions.
I`so*u"ric (?), a. [Iso- + uric.] (Chem.) Pertaining to, or
designating, a complex nitrogenous acid, isomeric with uric acid.
Is"ra*el*ite (?), n. [L. Israëlites, Gr. &?;, fr. &?;, &?;, Israel,
Heb. Yisr&?;l, i. e., champion of God; srh to fight + &?;l God.] A
descendant of Israel, or Jacob; a Hebrew; a Jew.
{ Is`ra*el*it"ic (?), Is"ra*el*i`tish (?), } a. Of or pertaining to
Israel, or to the Israelites; Jewish; Hebrew.