rotation 
cells, as in Cliara and J~<illiiieri<t. See below. 3. 
Serial or recurrent order; a round or sequence 
of one after another ; a fixed or definite routine 
of succession; regularly recurring change. 
I have often observed particular words and phrases 
come much into vogue. . . . This has lately been remark- 
able of the word rotation. . . . Nothing is done now but 
by rotation. . . . [In] whist, they play the rubbers by ro- 
tation; a fine lady returns her visits by rotation; and the 
parson of our parish declared yesterday that . . . he, his 
curate, the lecturer, and now and then a friend, would for 
the future preach by rotation. 
5237 
The rotation-area for an axis may be exhibited geomet- 
rically by a portion of the axis which is taken proportional 
to the area, and it is evident from the theory of projec- 
tions that rotation-areas for different axes may be com- 
bined by the same laws with which forces applied to a 
point and rotations are combined, so that there is a cor- 
responding parallelepiped of rotation-areas. There is, 
then, for every system, an axis of resultant rotation-area, 
with reference to which the rotation is a maximum, and 
the rotation-area for any other axis is the corresponding 
projection of the resultant rotation-area. The rotation- 
area vanishes for an axis which is perpendicular to the rotcll (roch), n. 
axis of resultant rotation-area. 
B. Peirce, Analytical Mechanics, 764. 
rote 
and solutions, of rotating the plane of polarization. See 
rotatory polarization. Rotatory steam-engine. See 
steam-engine. Specific rotatory power, the angle of 
rotation which a layer of unit thickness would give to a 
certain light-ray; practically, an assumed color called 
the transition-tint. 
II. . ; pi. rotatories (-riz). In zoijl., a rota- 
torian or rotifer. 
The rotatories fix the posterior extremity of the body. 
Vander Uoeven, Zool. (trans.), I. 196. 
British Mag., 1763, p. 542, quoted in N. and Q., 7th ser., ' 
[VII. 164. rotative (ro'ta-tiv), . [< F. rotatif, < L. rota- 
tus, pp. of rotare, rotate: see rotate.] 1. Caus- 
ing something to rotate; producing rotation. 
The rotative forces acting on A and B are, as it were, 
distributed by the diurnal rotation around NS. 
Newcomb and Uolden, Astronomy, p. 211. 
2. Pertaining to rotation ; rotational. 
Angular velocity of rotation. When a solid body re- 
volves about an axis, its different particles move with a 
velocity proportional to their respective distances from 
the axis, and the velocity of the particle whose distance 
from the axis is unity is the angular velocity of rota- 
tion. It is often expressed as in turns per second. 
Axial rotation. See axial. Axis of rotation. See 
axis*. Center of rotation, the point about which a 
body revolves. It is the same as the center of motion. 
Center of spontaneous rotation, the point about which 
a body all whose parts are at liberty to move, and which , 
has been struck in a direction not passing through its TOtatlVely (ro ta-tiv-ll), OM 
center of gravity, begins to turn. If any force is im- in a rotatory manner. 
pressed upon a body or system of bodies in free space, A taternan y.toothed wheel c, rotatively connected with 
and not in a direction passing through the center of grav- the said shaft The Engineer LXIX 290 
ity of the body or system, a rotatory motion will ensue 
about an axis passing through the center of gravity, and rotatO-plane (ro ta-to-plan), a. Same as rotate- 
the center about which this motion is performed is called 
the center of spontaneous rotation. Circular rotation 
of the eyeball, rotation about the visual axis. Congru- 
ency of rotations. See congruency. Couple of rota- 
tions. See couple. Energy of rotation. See eneryy. 
Magnetic rotation of currents. See magnetic. Mag- 
Same as roach 2 , 2. [Prov. 
ig-] 
jChe (roch), n . [Said to be < D. rotje, a petrel ; 
cf. G. dial, ratschc, G. rdtsch-ente, the common 
wild duck, < ratschen, rdtsclten, splash like a 
duck.] The little auk, auklet, dovekie, or sea- 
dove, Meryulus alle or Alle iiigrieans. See Mer- 
gulus, Alle, and cut under dovekie. 
rotchett, . Same as rochet 2 . 
rotchie, Same as rotclie. 
equatorial rise of the solar atmosphere. 
Siemens, New Theory of the Sun, p. 21. 
So as to rotate ; 
This high rotative velocity of the sun must cause an _+-]. (r 5 t ) . r< ME. rot, root, rote, < OF. rote, 
mat/trial ria nf th<* Bnliir ftt innsnnfirR. ' , 
route, roupte, a way through a forest, a way, 
road, track, rut, F. route, a way, road, track, 
= Sp. ruta = Pg. rota, track, course of a ship 
at sea (ML. reflex rotta, rota), < ML. rupta, 
a way through a forest, a way, road, street; 
prop, adj., sc. ria, a way broken or cut through 
a forest; < L. rupta, fern, of ruptus, pp. of rum- 
pere, break: see rupture. Bot& is thus a doub- 
let of route 1 , rouft, rut 1 , q. v. Cf. routine.] 1. 
A fixed or unchanging round, as in learning 
or reciting something; mechanical routine in 
learning, or in the repetition of that which has 
(ro-ta'tor), n. [= F. rotateur = Sp. 
rodador =' Pg. rotador = It. rotatore, < L. ro- 
tator, a whirler, < rotare, whirl, rotate: see 
rotate.] 1. One who or that which rotates, 
netic rotation of the plane of polarization. Seemo^- i-nraHnn nnv rotational asrencv or """"'"Si "' " """ "'i"'""" 1 .' V v "" v ~", 
netic rotatory polarization, under rotatory.- Method of ? r causes rotation, any rotauonai agency o been i earne( j. exact memorizing, or reproduc- 
rotations.a method used in descriptive geometry, consist- =<~""t 
, , - 
ing in turning apart of the given geometrical system about 
an axis, usually perpendicular to a plane of projection. 
Principal axes of rotation. If a point which is not 
the center of gravity be taken in a solid body, all the axes 
instrument. 
This is mounted on the rotator, so that it can be turned 
around quickly. Mayer, Sound, p. 110. 
2. Specifically, in anat., a muscle that pro- 
wliich pass through" that point (and they may be infinite duces a rolling or rotatory motion of a part; a 
) n ,,mh,\ iii hav,, rtitf-rBnt. m omm,t nf inertia, and mugcle w hi c h rotates a part upon its own axis. 
[In this sense usually as New Latin, with plural 
rotatores.] 3. In metal-working, a revolving 
or rotary furnace Rotatores dorsi. Same as ro- 
tatores epinee. Rotatores femoris, six muscles which in 
the human subject rotate the femur and evert the thigh : 
they are the pyriformis, quadrat us, obturator externus and 
internus, with the gemellus superior and inferior. Ro- 
tatores spinse, several (about eleven) small deep-seated 
muscles of the thoracic region of the spine beneath the 
mult ilidns, passing obliquely from the transverse process 
of a vertebra to the lamina of the next vertebra above. 
Also called rotispinales. Rotator flbulse, the rotator of 
the fibula, a muscle of the leg of some animals, as lemurs, 
from the back of the tibia obliquely downward and out- 
ward to the front of the fibula. 
in number) will have different moments of inertia, and 
there must exist one in which the moment is a maximum, 
and another in which it is a minimum. Those axes in 
respect of which the moment of inertia is a maximum or 
minimum are called the principal axes of rotation. In 
every body, however irregular, there are three principal 
axes of rotation, at right angles to each other, on any one 
of which, when the body revolves, the opposite centrifu- 
gal forces counterbalance each other, and hence the ro- 
tation becomes permanent Principle Of the compo- 
sition of rotations, the proposition that three rotations 
about axes which meet in one point are equivalent to one 
rotation round an axis through the same point, the measure 
of the rotations being taken upon the axes, and the axis of 
the resultant rotation being the diagonal of the parallele- 
piped of which the others are sides. Pure rotation, ro- 
tation without translation ; a screw-motkm where the pitch 
of the sere' 
the .-am 
cally, 
byappoi , _ 
intervals, without regard to the manner in which their rotatorial (ro-ta-to'ri-al), a. [< Itotatoria 
duties have been discharged. In the United States the ^TiT* ;, * oW- u ;,,,- t H, a ;?#/ 
principle of rotation in appointive offices has been both 
advocated and condemned with great urgency on grounds 
of public advantage and partisan or personal right. 
Jefferson would have rotation in office. 
Theodore Parker, Historic Americans, p. 260. 
-/.] In zool., of or pertaining to the Botatoria 
or Botifera; rotiferal. 
rotatorian (ro-ta-to'ri-an), re. [< Botatoria + 
-an.] A member of the Botatoria; a rotifer or 
wheel-animalcule. 
Rotation Of crops, a recurring series of different crops 
grown on the same ground ; the order of recurrence in 
cropping. It is found that the same kind of crop cannot 
be advantageously cultivated on the same soil through a 
succession of years, and hence one kind of crop is made 
to succeed another in repeated series. Different soils and 
The tiny creature, as it develops, shows itself a rotato- 
rian. The Century, XIV. 154. 
tion from memory, as of words or sounds, with 
or without attention to their significance : chief- 
ly in the phrase by rote. 
Loke a ribaut of hem that can noujjt wel reden 
His rewle ne his respondes but be pure rote, 
Ala as he were a connynge Clerke he casteth the lawes. 
Piers Plowman's Crede (E. E. T. S.), 1. 377. 
First, rehearse your song by rote, 
To each word a warbling note. 
Shale., M. N. D., v. 1. 404. 
He rather saith it by rote to himself, as that he would 
have, than that he can thoroughly believe it, or be per- 
suaded of it. Bacon, Atheism (ed. 1887). 
The lazy manner of reading sermons, or speaking ser- 
mons by rote. Goldsmith, The Bee, No. 7. 
2. A part mechanically committed to memory. 
[Rare.] 
A rote of buffoonery that serveth all occasions. Swift. 
3. A row or rank. [Prov. Eng.] 
been laid in 
song). 
, _ To 
learn by rote or by heart. 
Speak 
To the people ; not by your own instruction, . . . 
But with such words that are but rated in 
Your tongue. Shale., Cor., iii. 2. 55. 
2. To repeat from memory. 
And if by chance a tune you rote, 
'Twill foot it finely to your note. 
Drayton, Muses' Elysium, ii. 
rotatory (ro'ta-to-ri), a. and . [=.rotatoire, r ote 2 t (rot), r. i. [< L. rotare, whirl, rotate: see 
< NL. "rotatorius, < L. rotator, a whirler, < ro- rotate.] To rotate; change by rotation. 
tare, whirl, rotate: see rotate.] I. a. I. Of, 
this modell upon 
recognized rule in all cases that culmiferous crops ripen- - 
ing their seeds should not be repeated without the inter- causing to turn about or upon an axis or sup- 
vention of pulse, roots, herbage, or fallow. Rotation of port ; relating to motion from or about a fixed 
protoplasm, in bot., the circulation or streaming move- 
ment of the protoplasmic contents of active vegetable 
cells. Under a moderately high power of the microscope 
the protoplasm of vitally active cells is seen to be in a state 
of constant activity or rotation that is, it flows or moves 
about in steady streams or bands in various directions in- 
side the cell. These moving protoplasmic bands have em- 
bedded in them minute granules. The rate of the move- 
ments varies in different plants, being (at a temperature 
of 15" C.) only .009 millimeter per minute in the leaf-cells 
of Potamogetnn crispus, and 10 millimeters per minute in 
the plasmodium of Didytnium Serpula. See protoplasm. 
Rotation of the plane of polarization. See rota- 
tory polarization, under rotatory. 
rotational (ro-ta'shon-al), a. [< rotation H- 
-al.] Pertaining to or consisting in rotation; 
of the nature of rotation: as, rotational velo- 
city. 
We should thus be led to find an atom, not in the rota- 
tional motion of a vortex-ring, but in hrotational motion 
round a re-entering channel. 
W. E. Clifford, Lects., I. 242. 
Rotational motion of a fluid. See vortex-motion. 
rotation-area (r9-ta'shon-a''re-a), n. Double 
the sum of the products obtained by multiply- 
ing each element of mass of a material system 
by the differential coefficient relative to the 
time of the area described by the radius vector 
upon the plane perpendicular to the axis of ro- 
tation. If all the external forces which act upon a sys- 
tem are directed toward an axis, the rotation-:irea for that 
axis will be described with a uniform motion, which is 
the principle of the conservation of areas. 
point or center : opposed to reciprocatory. 
The ball and socket joint allows ... of a rotatory or 
sweeping motion. Paley, Nat. Theol., ix. 
Verdet demonstrated that when a salt is dissolved in 
water the water and the salt each bring into the solution 
their special rotatory power. 
Atkinson, tr. of Mascart and Joubert, I. 576. 
My lady with her fingers interlock'd, 
And rotatory thumbs on silken knees. 
Tennyson, Aylmer's Field. 
third 
every ninth yeare the House would be wholly altered. No 
magistrate to continue above 3 yeares. 
Aubrey, Lives, J. Harrington. 
A third part of the senate, or Parliament, should rote out 
by ballot every year, and new ones to be chosen in their 
room. Z. drey, Note on Hudibras, II. iii. 1108. 
rote 3 (rot), n. [< ME. rote, roote, < OF. rote (= 
Pr. OSp. rota) = OHG. hrottd, rotta, rota, rod- 
da, MHG. rotte, < ML. rotta, rota, rocta, earlier 
ehrotta, a kind of fiddle, a crowd ; of Celtic 
origin: < W. crirth = Olr. crot = Gael, cruit, a 
fiddle, crowd: see crowd 2 .] A musical instru- 
2. Going about in a recurrent series; moving ment with strings, and played either by a bow, 
from point to point; following in succession: like a crowd or fiddle, or by a wheel, like a 
as, rotatory assemblies. Burke. (Imp. Diet.) hurdy-gurdy. 
3. In zool., rotatorial or rotiferal, as a wheel- 
animalcule. 4. In anat., causing rotation: as, 
There were two sets of instruments in the middle ages 
very similar to each other, the one played with the fingers, 
the other with a bow. The term Rote may perhaps have 
See croicrf 2 . Also called rota. 
Wel couthe he synge and pleyen on a rote. 
Chaucer, Gen. Prol. to C. T., 1. 236. 
a rotatory muscle Magnetic rotatory polariza- 
tion, that rotation of the plane of polarization, + or , 
which takes place when a plane-polarized beam of light is 
transmitted through a transparent medium in a powerful been applied to both classes, 
magnetic field, and similarly when it is reflected from the W. K. Sullivan, Introd. to O Curry s Anc. Irish, p. ii. 
poleof a powerful electromagnet. Magnetic rotatory r oteH r. i. An obsolete dialectal form of rouft. 
power. See magnetic.- Rotatory dlarthrosiS. Same * f 4 ", = t . . r-A j: a i ..- (1 f rf> , lt l or r ,,<2 1 
as cyclarthrosis.--RotSitOTy muscle, a rotator. -Rota- ri H' "_ L A ' 
tory polarization, the change of plane to the right or 
to the left (of an observer looking in the direction the ray 
is moving) which a ray of plane-polarized light undergoes 
when passed through quartz, sugar, etc. : if the rotation 
is to the right, the substance is said to be dextrorotatory 
(or positive), as cane-sugar and glucose ; if to the left, it 
is called lecorotatory (or negative), as starch-sugar, qui- 
nine, eti-. SIT also 'magnetic rotatory polarization, above. 
Rotatory power, the property which is possessed by 
some crystalline bodies, and a great number of liquids 
The sound of surf, as before a storm. [Local, 
Eng. and U. 8.] 
Then all amaz'd shriekes out confused cries, 
While the seas rote doth ring their doleful knell. 
Mir. for Mags. (England's Eliza, st. 270), II. 895. 
I hear the sea very strong and loud at the north. . . . 
They i':ill this (he rate or rut of the sea. 
D. Webster, Private Correspondence (ed. Fletcher Web- 
[ster), II. 262. 
