isogoniostat 
l &MIL **JUJ1_3*L _"* ? . .*? 
Magnetic Isotfonic Lines for 1890. 
isogoniostat (i-so-go'ni-9-stat), n. [< Or. tao- 
JIJWH;, equiangular (see isogon), + orarof, ver- 
bal adj. of iaravai, stand: see static.] A link- 
work for regulating the motion of a train of 
prisms. 
isogonism (i-sog'o-nizm), n. [< isogon-ic? + 
-is m.] In biol., production of similar or identi- 
cal sexual organisms or reproductive parts from 
diverse stocks. 
Medium) of Identical structure, which one would place 
In the same genus, may form the sexual generations of 
hydroid stocks belonging to different families (isiytituan). 
Clam, Zoology (trans.), I. 240. 
isogram. (i'so-gram), n. [< Gr. laof, equal, + 
ypa/jfta, that which is drawn or written: see 
aranfl, and of. diagram, etc.] A diagram ex- 
hibiting a family of curves for the purpose of 
showing a relation between three variables. 
isographic (I-so-graf 'ik), a. [< isography + -ic.] 
Of or pertaining to isography. 
isographically (i-so-graf'i-kal-i), adv. In an 
isographic manner ; as regards, or by means of, 
isography. 
The laborious process of isagraphically charting the 
whole of Argelanuer's 324,000 stars. 
A. M. Clarke, Astron. In 19th Cent, p. 487. 
isography (i-sog'ra-fi ), n. [< Or. o>pa0of, writ- 
ing like, < to-of, equal, + ypafytiv, write.] The 
imitation of handwriting. 
Isogynae (i-soj'i-ne), n. pi. [NL., < Gr. lo-oc, 
equal, + ywfi, female (in mod. bot. a pistil).] 
A division of dicotyledonous plants, including 
the Primulacete, Ericacew, etc., in which the 
carpels equal the sepals and petals in number. 
They are coextensive with the Isocarpte. 
isogynous (I-soj'i-nus), a. [< Gr. io-of, equal, 
+ ywi/, female (in mod. bot. pistil).] In bot., 
having the pistils, or the carpels of which the 
single pistil is composed, equal in number to 
the sepals. 
isogyrOUS (i-so-ji'rus), a. [< Gr. loot, equal, + 
ywpof, round: ee gyre.] In bot., forming a com- 
plete spire. [Rare.] 
isohalsine (i-so-hal'sin), n. [Irreg. < Gr. loos, 
equal, + a/If, salt, + -tne 1 .] A line connecting 
points of equal salinity in the waters of the 
ocean. Such lines may be drawn to Indicate either the 
distribution of the saline matter (about three fourths of 
which in the main ocean consists of common salt) at and 
near the surface, or its variations in depth. In the latter 
case, the isohalslnes are plotted upon a plane surface rep- 
resenting a vertical section of the ocean between the de- 
sired pointa. 
isohyetal (i-so-hl'e-tal), a. and n. [< Gr. looy, 
equal, + verof, rain: see hyetal.] I. a. Marking 
equality of rainfall: as, an isohyetal curve. Iso- 
hyetal lines may be drawn to connect places having the 
same amount of annual or of seasonal rainfall. An isohye- 
tal map or chart is more generally called a ntinjull chart. 
II. M. An isohyetal line or curve. 
isokephaly (i-so-kef'a-li), n. See isocephaly. 
isoklinostat, n. See isoclinostat. 
isolable (is'o- or i'so-la-bl), a. [< isol-ate + 
-able.'] That can bo isolated; specifically, in 
chem., capable of being obtained pure, or un- 
combiucd with any other substance. 
It [identityl is quite accurately distinguishable from 
difference in known matter, but it is not isolabU from dif- 
ference. B. Bosarufuet, Mind, XIII. 359. 
isolate (is'o- or i'so-lat), i: t. ; pret. and pp. iso- 
lated, Mfc itotottaf. [With suffix -ate*. < F. 
IN-,/, , = iv. i.inlar, < It. isolare, < ML. insulan; 
pp. iiixutatus, detach, separate: see insulate."] 
1. To set or place apart; detach or separate so 
as to be aloiie : often used reflexively : as, he 
isolated himself from all society. 
It IB ... possible to dissect out a nerve with a muscle 
attached, to keep it alive tor a time, and thus to inquire 
what an isolated nerve will do. 
Q. T. l.ii'l'l. Physlol. Psychology, p. 56. 
2. In elect., same as insulate, 3. 3. In them., 
to obtain (a substance) free from all its com- 
binations. 
isolate (is'o- or i'so-lat), . [< isolate, p.] Iso- 
lated; detached. 
3197 
The New .Moon swam divinely unfai* 
In maiden silence. Lowell, Endymlon, 1. 
isolated (is'o- or i'so-la-ted), p. a. 1. Stand- 
ing detached from others of a like kind ; placed 
by itsolf or alone. 
I am not teaching man's isolated energy. 
Channing, Perfect Life, p. 17. 
2. In rlii-iii., pure; freed from combination. 
Isolated bltaugent. See bitanyent. 
isolating (is'o- or i'so-la-tmg), p. a. Employ- 
ing the principle or ' producing the effect of 
isolation: specifically applied m philology to 
monosyllabic languages in which each word is 
a simple, uninflected root. 
Such languages (agglutinative], constituting the small 
minority of human tongues, are wont to be called iso- 
lating, I. e. using each element by Itself, in Its integral 
form. Whitney, Eucyc. Brit., XVIII. 774. 
isolation (is-o- or l-so-la'shou), . [= F. iso- 
lation; as isolate + -ion.] 'The state of being 
isolated or alone. 
Isolatum from the rest of mankind. 
Mil mini. Latin Christianity, vili. 5. 
God-like isolation which art mine, 
1 can but count thee perfect gain. 
Tennyson, Palace of Art. 
isolator (is'o- or i'so-la-tor), H. [< isolate + 
-or.] An insulator. 
isologous (i-sol'o-gus), a. [< Gr. loot, equal, + 
/djof, ratio, proportion: see logos.'] Having 
similar proportions or relations: specifically 
applied in chemistry to a series of Hydrocar- 
bons each member of which differs in composi- 
tion from the next above it in the same series 
by having two less hydrogen atoms. Thus, 
ethane (C 2 H 6 ), ethylene (CgH^, and acetylene 
(C 2 H 2 ) form an isologous series. 
The number of isologous groups actually known and 
studied is comparatively small. 
W. A. Miller, Elem. of Chem., i 1122. 
isologue (i'so-log), n. [< Gr. looc, equal, + f.o- 
yof, ratio, proportion.] A member of an isol- 
ogous series of hydrocarbons. 
isomastigate (I-so-mas'ti-gat), a. [< Gr. io-of, 
equal, + [idoTii- (poorer-), a whip.] Having the 
flagella alike or similar, as an infusorian, in 
which there may be two or more such flagella : 
distinguished from heteromastiqate. 
isomer (i'so-mer), n. [< Gr. loofiept/c, having 
equal parts: see isomerous.] In chem., a com- 
pound that exhibits the properties of isomerism 
with reference to some other compound. Also 
isomeride. 
Isomera (i-som'e-ra), n. pi. [NL. : see isomer- 
ous.] A primary division of coleopterous in- 
sects, characterized by having (with a very few 
exceptions) the same number of tarsal joints on 
the posterior legs as on the others. The Isomera 
include the five series Adephaya, Claoicornia, Serricornia, 
Lamellieornia, and Phytophaga. 
isomere (i'so-mer), n. [< Gr. 'iaofiepi/f, having 
equal parts: see isomerous. Cf. isomer.'] In 
zool., a part or segment of the limb of one ani- 
mal which is homologous with or corresponds 
to a part in another animal. Thus, the distal end 
of a bird's tibia is an isomere of proximal tarsal bones of a 
mammal. See isotome, and jiif moral segment (under mem- 
bral). 
The lines . . . are isotomes, cutting the limbs Into 
morphologically equal parts, or isomcret. 
Coues, Key to N. A. Birds, p. 229. 
isomeria (i-so-me'ri-a), n. [NL., < Gr. iaouefrijf, 
having equal parts: see isomerous.'] A distri- 
bution into equal parts. Kersey, 1708. 
isomeric (i-so-mer'ik), a. [< isomer-ous + -to.] 
1. In chem., pertaining to or characterized by 
isomerism. 
As I learn from one of our first chemists, Prof. Frank- 
land, protein is capable of existing under probably at 
least a thousand isomeric forms. 
U. Spencer, Prin. of Biol., App., p. 483. 
2. In :ool., of, pertaining to, or forming an iso- 
mere : as, isomeric segments of the limbs. 
isomerical (i-so-mer'i-kal), a. [< isomeric + 
-<il.'] Same as isomeric. 
isomerically (i-so-mer'i-kal-i), adv. In an iso- 
meric manner; as regards isomerism. 
isomeride (i-som'e-rid or -rid), n. [< isomer-on.i 
+ -/</<-.] Same as isomer. 
isomerism (i-som'e-rizm), n. [< isomer-ous + 
-ism.] In chem., identity or close similarity of 
composition and molecular weight, with differ- 
ence of physical or of both chemical and phy- 
sical properties. There are three different cases of 
isomerism : first, where compound bodies have the same 
ultimate composition and the same molecular weight, 
but differ in physical properties and in their behavior 
toward the same reagents, being essentially distinct sub- 
stances; second, where compounds have the same compo- 
sition, the same molecular weight, and the same general 
isomorphous 
reactions, but ditf er in certain physical or chemical prop- 
erties; tliinl, wtirrt- compounds differ solely In certain 
physical properties. The facts of isomerism are gener- 
ally explained by assuming a difference In the arrange 
meiit of the atoms which form the ttomeric molecule*. 
Allotropy stands In the same relation to elements that 
itamerum doe* to COIII|HHIM<|H. 
fr'rankUiud and Japp, Inorganic Chemistry, p. 111. 
isomeromorphism(i-89-mer-o-m6r'fizm), n. [< 
Gr. ioo//fpi/f,Tiaving equal parts (see isomerous), 
+ /M>p^,form,+ -i*i.J In crystal., isomorphism 
between substances having the same atomic 
proportions. 
isomerous (i-som'e-rus), a. [< Gr. iao/itp//t, hav- 
ing equal parts or'shares, < laof, equal, + ulpof, 
part, share.] 1. In hot., composed each of an 
equal number of parts, as the members of the 
several circles of a flower. 2. In chem., hav- 
ing the property of chemical isomerism . 3. In 
e/t tow., having the same number of tarsal joints 
of all the legs. When the number is not stated, 
isomerous tarsi are understood to be five-joint- 
ed or pentamerous. See Isomera. 4. laodon- 
tor/., having the same number of ridges : specifi- 
cally applied to molar teeth whose transverse 
ridges do not increase in number on successive 
teeth, as in the living elephants: opposed to 
anisomerons and liypisomerous. Gill. 
isomery (i'so-mer-i), . [< NL. isomeria, q. v.] 
Isomerism. 
isometric (I-so-met'rik), a. [< Gr. ia6/ierpof, of 
equal measure, < toof, equal, + fitrpov, measure.] 
1. Of equal measure. 
In The Princess we also find Tennyson's most successful 
studies upon the model of the Theocritan imnetric verse. 
Stedman. Viet. Poets, p. UK;. 
2. Iii crystal., pertaining to that system which 
is characterized by three equal axes at right 
angles to one another. The seven holohedral forms 
under this system are the cube, regular octahedron, rhom- 
bic dodecahedron, tetrahexahedron, tetragonal and trigo- 
nal trlsoctahedron, and hexoctahedron. The tetrahedron 
and pyritohedron are the most common hemihedral forms. 
Also called monometric, regular, tesndar, cubic. See rri/x- 
tattography. Isometric perspective or projection, a 
method of drawing figures of machines, etc. It is an or- 
thogonal projection on lines equally inclined to the three 
principal axes of the body to be represented. 
isometrical (i-so-met'ri-kal), a. [< isometric + 
-al.] Same as isometric. 
isometrograph (i-so-met'ro-graf), . [< Gr. 
iffof, equal, + /ifr/iov. measure, + ;/xi^m>, write.] 
An instrument for accurately spacing and draw- 
ing lines at equal distances from each other, as 
in cross-hatching sections in mechanical draw- 
ing. It consist* of mechanism which moves a straight- 
edge or ruler a definite distance parallel to itself, so that 
lines drawn along the edge of the ruler are equally spaced. 
isomorph (i'so-morf), H. [< Gr. icrof. equal, + 
lioptyij, form.] 1. A substance which exhibits 
isomorphism. 2. In ;oi>l., an organism which 
has the same form as another, and thus resem- 
bles it, though belonging to a different group. 
There are sandy forms [of the Rrtieularia\ which it Is 
difficult to separate from imperforate Lituolidea and are 
nevertheless perforate, in fact are "sandy isomorphi of 
Lageua, Nodosaria, Globigerina, and Rotalia." 
E. R. Lankester, Encyc. Brit, XIX. 849. 
isomorphic (i-so-mor'fik), a. [< isomorjih-ous 
+ -ic.J 1. Same as isomoriihoiis. 2. In biol., 
being of the same or like form ; morphologi- 
cally alike; equiformed. 
Dlcholophus . . . has assumed peculiar raptorial char- 
acters isomorphic with those of Gypogeranii*. which is a 
true bird of prey. Nature, XXXIX. 180. 
isomorphism (I-s6-m6r'fizm), n. K isonutrjjh-ous 
+ -ism.] A similarity of crystalline form: as, 
(a) between substances of analogous compo- 
sition or atomic proportions, as the members 
of a group of compounds like the sulphates of 
barium, strontium, and lead; (b) between com- 
pounds of unlike composition or atomic pro- 
portions. The first of these is isomorphism proper, and 
is sometimes distinguished as isomermu or aanomic iso- 
morphism ; the second as heteromerous or heteronamic iso- 
morphism, or simply as hmnaeomorpliism. Holohedral 
Isomorphism, in math., the identity of the form of two 
groups. 
isomorphous (i-so-mdr'fus). a. [< Gr. loot, 
equal, + pop^i;, form.] Exhibiting the prop- 
erty of isomorphism. Also isomorjMc. 
Notwithstanding the possibility, In the case of certain 
carbonates, of substituting isomorphma constituents for 
one another, it cannot be pretended that any evidence as 
yet breaks down the list of chemical elements. 
J. Jlartineau, Materialism, p. 127. 
Isomorphous group, (a) A group of substances having 
analogous composition and closely related crystalline form. 
Thus, in mineralogy, the carbonates of calcium, magnesi- 
um. iron, manganese, and zinc (respectively CaCOs, MgCOs, 
p, all 
FeCOs, MnCO 3 , ZnCO 3 ) form an isomorphous group, 
crystallizing in the rhombohedral system, and with near- 
ly the same angles, the angle of the cleavage rhombohe- 
