228 
M O T 
MOT 
M O T 
their general food ; but in defect of these they 
will eat many other things. No bird is so 
tame and familiar as this; closely attending 
the heels of the gardener when he is using 
his spade, tor the sake of worms ; and fre- 
quently in winter entering houses where win- 
dows are open, when they will pick up the 
crumbs from the table while the family is at 
dinner. Its familiarity has caused a 'petty 
name to be given it in several countries. The 
people about Bornholm call it Tommi-liden; 
m Norway, Peter-ronsmad ; the Germans' 
I homas-gierdet ; and we, the Robin-red- 
breast. 
9- The mnanthe, or wheatear, is in length 
five inches and a half. The top of the head, 
hind part ot the neck, and back, are of a 
blueish grey; and over the eye a streak of 
white; the under parts of the body yellowish- 
white : the breast is tinged with red ; and the 
legs are black. 1 his bird is met with in most 
parts of Europe, even as far as Greenland : 
and specimens have also been received from 
the East Indies. It visits England annually 
in the middle of March, and leaves us in Sep- 
tember. It chiefly frequents heaths. The 
nest is usually placed under shelter of some 
turf, clod, stone, or the like, always on the 
ground, and not ’.infrequently in some de- 
serted rabbit-burrow. It is composed of dry 
grass or moss, mixed with w y ool, fur of the 
rabbit, &c. or lined with hair and feathers. 
r fl he eggs are from five to eight in number, 
ot a light blue, with a deeper-blue circle at 
the large end. The young are hatched the 
middle of May. In some parts of England 
these birds are in vast plenty. About East- 
bourn in Sussex they are taken in snares made 
of horsehair placed beneath a long turf: 
being very timid birds, the motion of a cloud, 
or the appearance of a hawk, will drive them 
for shelter into these traps, and so they are 
taken. The numbers annually ensnared in 
that district alone amount to' about 1840 
dozen, which usually sell at sixpence per 
dozen. Quantities oi these are eaten on the 
spot by the neighbouring inhabitants ; others 
aie picked, and sent up to the London poul- 
terers ; and many are potted, being as much 
esteemed in England as the ortolan on -the 
continent Their food is insects only; 
though in rainy summers they feed much on 
earth-worms, whence" they are fattest in such 
seasons. 
10. The cyanea, or superb warbler, a most 
beautiful species, is live inches and a half 
long. The bill is black ; the feathers of the 
dead are long, and stand erect like a full crest; 
from the forehead to the crown thev are of a 
bright blue : thence to the nape, black like 
velvet; through the eves from the bill there 
runs a line ot black ; and beneath the eye 
springs a tuft of the same blue feathers ; be- 
neath which, and on the chin, it is of a deep 
blue, almost black, and feeling like velvet, 
f he hincUpart of the neck, and upper parts 
of the body and tail, are of a deep blue-black, 
the under pure white; the wings are dusky ; 
the shafts of the quills cbesnut ; the le^s are 
dusky brown ; the claws black. It inhabits- 
\ an Diemen s Land, the most southern part 
ot New Holland, lire female of this species, 
is discovered to be entirely destitute of all the 
fine blue colours, both pale and dark, by 
which tire male is adorned, except that there 
is . a very narrow circle of azure round each 
eye, apparently on the skin only. 
11. T he troglodytes, or wren, is a very 
small species, in length only three inches and 
three quarters, though some have measured 
four inches. It generally carries the tail 
erect. This minute bird is found throughout 
Europe; and in England it defies our severest 
winters. Its song is much esteemed, being, 
though short, a pleasing warble, and much 
louder than could be expected from the size 
of the bird; it continues throughout the year. 
The sylvia builds in low bushes, and lays 
five pale-green eggs, sprinkled with reddish 
spots. See Plate Nat. Hist. fig. 271. 
Above 150 other species, besides varieties, 
are enumerated by ornithologists. 
MO I E, in law-books, signifies court, meet- 
ing, or convention, as a ward-mote, burgh- 
mote, swain-mote, &c. 
MOTH. See Phal.ena. 
MOTION, has been defined to be “ a 
change of place,” or 1 lie act by which a body 
con esponds with different parts of space at 
different times. 
M e are principally acquainted with two 
sorts of motion in the beings that surround 
us; one is the motion by which an entire 
body is transferred from one place to another, 
as that of a stone when it falls, or of a ship 
under sail, k is this species of motion which 
most frequently comes under our observation, 
and with which we are best acquainted. But, 
besides this, there is another kind of motion. 
which, though not so obvious, is yet not less 
common nor important. This is a motion of 
the parts of bodies among themselves, which 
though sometimes the object of our senses, 
yet in other cases we require the aid of re- 
flection to be convinced of its existence. It 
is by this imperceptible motion that plants 
and animals grow, and by which the greatest 
number of the compositions and decomposi- 
tions throughout the globe take place. We 
may form some idea of this, by observing the 
continual motion of the light particles which 
sometimes float about in water, when it is 
held in the rays of the sun, which proves, 
that the parts of the water themselves are in 
constant motion. But if we reflect a little, we 
shall discover that the particles of the most 
solid bodies are also continually changing ' 
their situations. Heat expands, and cold 
contracts, the size of all bodies ; now, we 
know from experience, that the temperature 
of bodies is constantly varying, consequently, 
the particles must be in continual agitation, 
in order to adapt themselves to the size of the 
body. 
T he communication of motion from one 
body to another, though a feet with which 
we are well acquainted, we are equally inca- 
pable of accounting for. J t is, however, of 
the utmost importance in mechanics, which 
is indeed an art derived from the study of its 
laws. In considering motion, several circum- 
stances must be attended to: 
1. The force which imoresses the motion. 
?. The quantity of matter in the moving 
body. 3. The velocity and direction of the 
motion. 4. The space passed over by the 
moving body. 5. Tire time employed in 
going over this space. 6. The force with 
which it strikes another body that is opposed 
to it. 
In a mechanical sense, every bodv, by its 
inertia, resists all change of state, if at rest, 
ii will not begin to move of itself; and if mo- 
tion is communicated to it by another body, 
it will continue to move for ever uniformly, 
except it is stopped by an external agent. It 
is true, we do not see any instances of bodies 
continuing to move for ever, after being once 
put in motion; but the reason of this is that 
all the bodies which we see are acted upon 
in such a manner, as to have their motion 
gradually destroyed by friction, or the rub- 
bing of other bodies upon them. For if you 
diminish the friction by any means, the mo- 
tion will continue much longer; but as it is 
impossible to destroy it entirely, it diminishes 
and at last destroys, all motions on the surface 
of the earth. To put a body in motion, 
therefore, there must be a sufficient cause! 
T hese causes are called motive powers, and 
the following are those generally used in me- 
chanics ; the action of men and other animals 
wind, water, gravity, the pressure of the at-’ 
mosphere, and the elasticity of fluids and 
other bodies. 
The velocity of motion is estimated by the 
time employed in moving over a certain 
space, or by the space moved over in a cer- 
tain tune. To ascertain the degiee of this 
swiftness or velocity, the space run over must 
be divided by the time. For example: sup- 
pose a body moves over 1000 yards in io 
minutes, iis velocity will be 100 yards per 
minute. It we would compare the' velocity 
of two bodies A and B, of which Amoves 
over 54 yards in 9 minutes, and B 96 yards 
in 6 minutes, the velocity of A will be to that 
of b, in the proportion or 6 (the quotient of 
54 divided by 9) to 16 (the quotient of 96 di- 
vided by 6). 
To know the space run over, the velocity 
must be multiplied by the time; for it is 
evident, that it either the velocity or the 
time is increased, the space run over will be 
greater. If the velocity is doubled, then the 
body will move over twice the space in (he 
same time; or if the time is twice as great, 
then the space will be doubled ; but if the 
velocity and time are both doubled, then will 
the space be four times as great. 
It follows from this, that when two bodies 
move ovc r unequal spaces in unequal times, 
their ve’qcities are to each other as the quo- 
tients arising from dividing the spaces run 
o\ ei b_\ the times. If two bodies move over 
unequal spaces in the same time, their velo- 
cities will be in proportion to the spaces 
passed over. And if two bodies move over 
equal spacss in unequal times, then their re- 
spective velocities will be inversely as the 
time employed ; that is, it A in one minute, 
and B in two minutes, run over 1 00 yards’ 
the velocity of A will be to that of B as 2 to 1.’ 
A body in motion must every instant tend 1 
to some particular point. It may either tend 
always to the same point, in which case the 
motion will be in a straight line; or it may 
lie continually changing the point to which 
its motion is directed, and this will produce a 
curvilinear motion. 
If a body is acted upon only by one force, 
or by several in the same direction, its mo- 
tion will be in the same direction in which the 
moving force acts; as the motion of a boat 
which a man draws to him with a rope. But 
if several powers, differently directed, act 
upon it at the same time, as it cannot obey 
them all, it will move in a direction some- 
where between them. 
ibis is what is called the composition and- 
8 
