gyre 
Which from their proper orbs not go, 
Whether they ffyre swift or slow. 
Draiiton, Eclogues, ii. 
II. trans. To turn. 
September is with April! houres even, 
For Plielms like in either qireth heven. 
Palladiui, Husbondrie (E. E. T. S.), p. 186. 
gyre-carlin (gir'kar'lin), n. [Sc., also written 
iji/re-ciiiiiiii , t/i/i-c-f(i>iiii</_, t/y-ctirliH, gay-carlin, 
etc. ; < Icel. gygr (pi. gygjur) = Norw. gjure, a 
witch, an ogress, + Icel. harlinna, > Sc. eurliii, 
q. v.] A hag; a witch. 
There is a bogle or a brownie, a witch or gyre-carline, 
a bodaeh or a fairy in the case. 
Scott, Chronicles of Canongate, viii. 
gyrefult (jiv'ful), a. [< gyre + -fill. Cf. gerful.] 
Abounding in gyres or spiral turns ; revolving ; 
encircling. 
Suche posters may be likened well vnto the carters oulde 
Of forayne worlde, on Mount Olimpe whose carts when 
they were rould 
With gyrefull sway, by coursers swifte, to winne the glis- 
tring branche, etc. Drant, tr. of Horace's Satires, i. 2. 
Gyrencephala (jir-en-sef'a-la), n. pi. [NL., < 
Gr. yvpof, a ring, circle, + iyKifyakof, the brain.] 
In Owen's system (1857), one of four prime divi- 
sions of mammalians, containing the orders Ce- 
tacea, Sirenia, Hyracoidea, Proboscidea, Ungu- 
lata, Carnivora, and Quadru mana, having more 
or less numerous cerebral gyri, and the hemi- 
spheres of the cerebrum extending more or less 
over the cerebellum and olfactory lobes of the 
brain : distinguished from Archencephala, Lis- 
sencephala, and Lyencephala. The division repre- 
sents the higher series of mammals called by Bonaparte 
JEducabilia and by Dana Megasthena, but differs in ex- 
cluding man. [Not in use.] 
gyrencephalate (jir-en-sef 'a-lat), a. [As 
Gyrencephala + -ate 1 .] Same as gyrencepha- 
lous. 
gyrencephalous (jir-en-sef'a-lus), a. [As Gy- 
rencephala + -oils.] Pertaining to or having the 
characters of the Gyrencephala. See cut under 
gyrus. 
gyrfalcon (jer'fa'kn), n. See gerfalcon. 
' , n. Plural of gyrus. 
nidas (ji-rin'i-de), n. pi. [NL., < Gyrinus 
-id<e.~] A family of hydradephagous beetles, 
the whirligigs, so called from 
their habit of gyrating to- 
gether on the water. Theme- 
tasternum has no antecoxal piece, 
but is prolonged in a triangular 
process posteriorly ; the antenna? 
are irregular and very short ; the 
abdomen has 7 segments, and there 
are 4 eyes, the upper pair of which 
look into the air, and the lower into 
the water. When disturbed they 
eject an odorous fluid. The larva? 
breathe by pairs of ciliate gills, 
one on each side of each of the ab- 
dominal segments, and the gills 
serve also as swimming-organs. 
Also called Gyrinida, Gyrinides, 
Gyrinites, and Gyrinoidea. 
Gyrinus (ji-ri'nus),. [NL., 
\ Gr. yvpivof or yi'pivof, a 
tadpole, porwiggle (so called 
from its round shape), < ji'pof, round: see gyre, 
n.~] A genus of water-beetles, typical of the 
family Gyrinidce, having the scutellum distinct. 
gyrlandt, and v. An obsolete form of gar- 
land. 
Their hair . . . gyrlaiided with sea grasse. 
B. Jomon, Masque of Blackness. 
gyrlet, See girl. 
gyroceran (ji-ros'e-ran), a. Resembling or re- 
lated to the genus Gyroceras. A. Hyatt. 
Gyroceras (ji-ros'e-ras), . [NL., < Gr. yvp6(, 
round, + Kepaf, a horn.] 
The typical genus of 
Gyroceratidce. Goldfuss. 
Also Gyroceratites, Gyro- 
cerus. 
Gyroceratidae (jir-o-se- 
rat'i-de), n. pi. [NL.,< 
Gyroceras (-at~) + -idee. ] 
A family of nautiliform 
shellsof a discoidal shape, 
in which the last whorl is parallel with the 
others, all being unconnected. 
gyroceratite ( jir-o-ser'a-tit), n. A fossil ceph- 
alopod of the family Gyroceratidce. 
gyroceratitic (jir-o-ser-a-tit'ik), a. [< gyro- 
ceratite + -ic.~] Kesembl'iug the Gyroceratidce; 
having unconnected whorls, as a fossil cepha- 
lopod. 
The loosely coiled [shell] but with whorls not in con- 
tnri, gyroceratitic. Science, III. 123. 
gyrodactyli, n. Plural of gyrodactylus, 2. 
Whirligig (Dinentes 
vittatits). one of the Gy. 
rtnitte. (Line shows nat- 
ural size.) 
Gyroceras goldfussi. 
2060 
Gyrodactylidae (jir"o-dak-tiri-de), . pi. [NL., 
<<li/riKla<-li/!ny + -ida:] A family of very small 
viviparous trematode worms with strong hooks 
and large terminal caudal disk. They are pro- 
duced one at a time, and within each, before it is born, 
another of a second generation may be formed, and in this 
again a third. 
Gyrodactylus (jir-o-dak'ti-lus), H. [NL. (Nord- 
mann), < Gr. yvpuf, round, 4- SCIKTV'AOC, finger.] 
1. The typical genus of trematode worms of 
the family Gyrodactylidce. G. elegans is found 
in the gills of fishes. 2. [1. c. ; pi. gyrodai'tijli 
(-15).] An individual or a species of this genus. 
gyrogonite ( ji-rog'o-nlt), . [< Or. yvpdf, round, 
+ yovof, seed, + -ife 2 .] A petrified spiral seed- 
vessel of plants of the genus Ckara, found in 
fresh-water deposits, and formerly supposed to 
be a shell. 
gyroidal (ji-roi'dal), a. [< Gr. yvpouSfc, like a 
circle, < yvpof, a circle, + e!oc, form.] Spiral 
in arrangement or in movement. () in crystal., 
having certain planes arranged spirally, so that they in- 
cline all to the right or all to the left of a vertical line. 
(6) In optics, turning the plane of polarization circularly or 
spirally to the right or left, 
gyrolite (jir'o-lit), . [< Gr. yvp6f, round, + 
/ii'fof, a stone.] A hydrous silicate of calcium 
occurring in white spherical forms with a radi- 
ated structure. 
gyroma (ji-ro'ma), n. ; pi. gyromata (-ma-ta). 
[< Gr. as if "yvpa/ia, < yvpovv, make round, 
bend, < yvp"f, round: see gyre."} 1. A turn- 
ing round. 2. In bot., the shield of lichens. 
Imp. Diet. 
gyromancy (jir'o-man-si), . [= P. gyroman- 
cie, < Gr. yvpof, a circle, 4- fiavrcia, divination.] 
A kind of divination said to have been prac- 
tised by walking round in a circle or ring until 
the performer fell from dizziness, the manner 
of his fall being interpreted with reference to 
characters or signs previously placed about the 
ring, or in some such way. 
gyromata, . Plural of 'gyroma. 
gyron, giron (jl'ron), w. [< F. giron, a gyron. 
so called in reference to the arrangement of gy- 
rpns round the fesse-point; < Gr. yvpos, a ring, 
circle: see gyre.'] In her., a bearing consisting 
of two straight lines drawn from any given 
part of the field and meeting in an acute angle 
in the fesse-point. It usually issues from the dexter 
chief, and is considered to occupy one half of the first 
quarter; but if otherwise, its position must be stated in 
the blazon. 
gyronnetty, gironnetty (jl-ro-net'i), a. [He- 
raldic F. gironnette, < * gironnette, dim. of giron : 
see gyron."] In her., finished at the top with 
points, as spear-points: said of a castle or tower 
used as a bearing. Also written gironnette. 
gyronny, gironny (ji'ro-ni), a. [Heraldic F. 
"gyronne, gironne, < gyron, q. v.] In her., divid- 
ed into a number of triangular 
parts of two different tinctures. 
The points of all the triangles meet at 
the fesse-point. The number of trian- 
gles must be stated in the blazon : as, 
gyronny of eight, or and gules. Also 
written gironne. 
Gyronny, covered with gyrons, or 
divided so as to form several gyrons ; 
said of an escutcheon. 
Booke of Precedence (E. E. T. 8., extra 
[ser.), i. 118. 
gyronwise, giron wise (ji'ron-wiz), adv. In 
her., in the direction of the lines forming a field 
gyronny that is, radiating from the fesse- 
point. 
Gyrophora (ji-rof'o-ra), . [NL., < Gr. 
a circle, + -ty6pn<;, < Qepeiv 
= E. bear 1 .'] A genus of 
lichens, one of which is 
the tripe-de-roche. 
gyrophoric (jir-o-for'ik), 
a. [< Gyrophora + -ic.\ 
Belonging to or derived 
from plants of the ge- 
nus Gyrophora: as, gyro- 
phoric acid. 
gyroscope (ji'ro-skop), n. 
[= F. gyroscope, a name 
given in 1852 by Foucault 
to his improved form of 
Bohnenberger's appara- 
tus, < Gr. yiipof, a circle, 
+ <TK07reZi>, view.] An in- 
strument consisting of a 
fly-wheel, the axis of 
which can turn freely in 
any direction, designed 
to illustrate the dynam- 
ics Of rotating bodies. Foucaulfs Gyroscope. 
Gyronny of eight, 
gules and argent. 
gyrostatic 
The instrument commonly called gyroscope is better named 
fyronopis top (which see, under yyroncopic). TbGMmaqpt 
proper of Foucault, shown in the figure, consists of a fly- 
wheel having the small conical bearings of its axis in a well- 
balanced metallic ring which carries two knife-edges in 
a line perpendicular to the axis of the fly-wheel; these 
knife-edges bear upon agates carried in a horizontal plane 
by an outer vertical ring half suspended from a small cop- 
per wire and turning about a vertical axis. The axis of 
the wheel can thus turn in any direction. By means of an 
accessory apparatus a velocity of 150 turns a second can 
be imparted to the fly-wheel. The principal experiments 
with this apparatus are as follows : First experiment. 
If, when the fly-wheel is turning rapidly, no considerable 
force is applied to change the direction of its axis, its di- 
rection will remain almost unchanged. P'or, suppose it 
were proposed, by an instantaneous impulse, to turn this 
axis round a fixed axis perpendicular to it; then, at the 
point where this fixed axis cuts the rim of the fly-wheel, 
a particle would have to be deflected, and it can be 
shown by the parallelogram of motions that a velocity 
must be communicated to it proportional to the velocity 
it already possessed. Hence, the force required to rotate 
the axis of a fly-wheel increases with its velocity. Ac- 
cordingly, when the velocity is very high, the friction on 
the bearings will change the direction of the axis but 
very little. But all the surrounding objects partake of 
the rotation of the earth upon its axis. Consequently, 
the axis of the fly-wheel will have a relative rotation ; 
and this may be observed with a microscope. Second 
experiment. If the fly-wheel was attached to its axis by 
a hinge, so that its plane was free to take any inclina- 
tion to the axis, it is plain that by virtue of centrifugal 
force it would become perpendicular to the axis, since in 
this way its particles would be furthest from the axis. If 
then the outer ring of the gyroscope be held fast in such 
a position that the axis of the fly-wheel is free to move 
in the meridian plane, it partakes of the rotation of the 
earth ; and the rotation of the earth and that of the fly- 
wheel being compounded, the axis of resultant rotation 
is not quite perpendicular to the fly-wheel. Accordingly, 
the inner ring will turn on its knife-edges until the axis 
of the fly-wheel is brought into parallelism with that of 
the earth, so that the wheel revolves from west to east 
like the earth. Third experiment. On the same princi- 
ple, if the outer ring be free to turn, but the inner one be 
fixed horizontally, the outer ring will turn so as to bring 
the axis of the fly-wheel into the meridian. Fourth ex- 
periment. Let the inner wheel be thrown out of balance 
by hanging a weight upon it near one end of the axis ; 
then this weight will each instant communicate a rota- 
tion about the knife-edges, compounding itself with the 
rotation of the fly-wheel about its axis as the rotation of 
the earth does in the third experiment, and a rotation of 
the outer ring round its vertical axis will result. Since 
the resultant axis of the first two rotations is very near 
that of the fly-wheel, the tendency of the weight to fall 
will be but slight, and under the influence of the centrifu- 
gal force of the third rotation it will move like a conical 
pendulum. Gyroscope governor, a steam-governor in 
which a gyroscope is employed as a regulator. A change 
in the speed of the engine causes a heavy gyroscope to 
change its plane of rotation, this change in turn control- 
ling the speed of the engine. See governor. 
gyroscopic (ji-ro-skop'ik), a. [< gyroscope + 
-ic.] Pertaining to the gyroscope ; illustrating 
the dynamical laws of rotation. 
The bearings are of great length and large diameter to 
stand the gyroscopic action which occurs in a heavy sea 
on board ship. The Engineer, LXVI. 364. 
Gyroscopic pendulum, an instrument consisting of two 
pieces, of which the first is attached to one of the axes of 
a universal flexure joint, 
the other axis being held 
fixed ; while the second 
piece is jointed to the 
first by an axis parallel 
to the fixed axis of the 
universal flexure joint. 
Gyroscopic top, an 
instrument consisting of 
a heavy fly-wheel revolv- 
ing about an axis one 
point of which is fixed, 
but which is otherwise 
free to move in any way. 
The fly-wheel being set 
in rotation, the axis 
moves about the fixed point in the manner explained 
under gyroscope, fourth experiment. 
gyrose (ji'ros), a. [< L. gyrus, a circle (see 
gyre), + -ose.~] In bot., turned round like a 
crook ; bent to and fro ; folded and waved or 
marked with wavy lines : applied to the pecu- 
liar and complicated flexuosities of the margin 
of the apothecium in the genus Umbilicaria. 
gyrostat (ji'ro-stat), n. [< Gr. yvp6c, round, 
yiipof, a circle, + orar<if, stationary : see stat- 
ic.] An instrument 
for illustrating the 
dynamics of rotation, 
composed of a box or 
case having a sharp, 
bearing-edge in the 
form of a regular poly- 
gon, and containing a 
fly-wheel having its 
center and its direc- 
tion of rotation in the 
plane of the bearing- 
edge. 
gyrostatic (ji-ro-staf- 
ik), a. [As gyrostat + 
Gyroscopic Top, or Gyroscope. 
Gyrostat. 
-ic.~] Connected with 
the dynamical principle that a rotating body 
tends to preserve its plUne of rotation. 
