MON 
denotes the same with infinitesimal. See 
Infinitesimal. 
MOMENTUM, in mechanics, signifies 
the same with impetus, or the quantity of 
motion in a moving body ; wliich is always 
equal to the quantity of matter, multiplied 
into the velocity; or, which is the same 
thing, it may be considered as a rectangle 
under the quantity of matter and velocity. 
If b denote a body and « the velocity 
of its motion, then b v will express or be 
proportional to its momentum m ; again if 
B be another body, and v its velocity, then 
M is = B V and M : m : : BV : bv. 
MOMORDICA, in botany, a genus of 
the Monoecia Syngenesia class and order. 
Natural order of Cucurbitaceae, Linnaeus 
and Jussieu. Essential character: calyx 
five-cleft; corolla, five-parted; male fila- 
ments three : female, style trifid ; pome 
opening elastically. There are eight spe- 
cies, the most remarkable of which is the 
M. balsamina, common mordica or male 
balsam apple : this has trailing stems like 
those of the cucumber and melon, extending 
three or four feet in length, sending out 
many side branches, which have tendrils ; 
leaves shaped like those of the vine, smooth, 
deeply cut into several segments; it is a 
native of India. This plant is famous in 
Syria for curing wounds ; the inhabitants 
cut open the unripe fruit, and then infuse 
it in sweet oil, exposed to the sun for some 
days, until the oil is become red. It is ap- 
plied to a fresh wound dropped on cotton ; 
the Syrians esteem this next to balsam of 
Mecca. 
MOMOTUS, the motmol, in natural his- 
tory, a genus of birds of the order Picse. 
Generic character : bill strong, slightly 
curved and serrated at the edges ; nos- 
trils feathered; tongue long, narrow, and 
feathered at the edges; tail wedge-form- 
ed. M. brasiliensis, or the Brasilian 
niotmot, is the only known species be- 
longing to this genus, and is about eigh- 
teen inches long, and nearly of tlie size 
of a magpie. It is seen almost always 
alone, and on the ground, on which it makes 
its nest, in a hole deserted by some of the 
smaller quadrupeds. It lives principally 
upon insects, and abounds in the close 
woods of Brasil, Cayenne and Mexico. It 
is not valued either for its flesh or song. 
MONADELPHIA, in botany, a single 
brotherhood : the name of the sixteenth class 
in Linnaeus’s system, consisting of plants 
witli hermaphrodite flowers, in which all the 
stamina, or male organs of generation, are 
united below into one body or cylinder, 
MON 
through which the pointal passes. Tlie 
principal characters are a permanent flower- 
cup, generally double ; five heart shaped pe- 
tals, closely embracing one another above ; 
the anthers, kidney-shaped ; the receptacle 
of the fructification, prominent in the mid- 
dle of the flower ; seeds kidney shaped. 
MONANDRIA, in botany, the name of 
the first class in Linnaeus’s Sexual System, 
consisting of plants with hermaphrodite 
flowers, which have only one stamen or 
male organ. This class is subdivided, like 
the other plain classes in the same system, 
from the number of the styles, or female or- 
gans, into tw o orders ; viz. those that have 
one style, and those that have two. 
MONARCHY, a government in which 
the supreme power is invested in a single 
person. There are several kinds of monar- 
chies, as where the monarch is invested with 
an absolute power, and is accountable to 
none but God. It is an error to suppose, 
that a despotic or absolute monarch is a 
solecism in politics, and that there can be 
none .such legally ; for the contrary is true, 
and that in dilFerent parts of the world, and 
fi'om various principles. In China it is 
founded on paternal authority, and is the 
basis of the government; in Turkey, Persia, 
Barbary, and India, it is the effect of reli- 
gion ; and in Denmark, the king is legally 
absolute by the solemn surrender which the 
people made to his predecessor of their li- 
berties. Another kind of monarchy is that 
which is limited, where the supreme power 
is virtually in the laws, though the majesty 
of government and the administration is 
vested in a single person. Monarchies are 
also either hereditary, where the regal 
power descends immediately from the pos- 
sessor to the next heir by blood ; or elective, 
where the choice depends upon all who en- 
joy the benefit of freedom, or upon a few 
persons in whom the constitution vests the 
power of election. The dangers 'of mo- 
narchy are, tyranny, into whicli it is liable 
to degenerate; expence; exaction; military 
domination; unnecessary wars, waged to 
gratify the passions of an individual; risk of 
the character of the reigning prince ; igno- 
rance in the governors of the interests and 
accommodation of the people, and a conse- 
quent deficiency of salutary regulations; 
want of constancy and unifinniity iu the 
rules of government ; and, proceeding from 
thence, insecurity of person and property. 
The advantages of this mode of government 
are, unanimity pf council, activity, decision, 
secrecy, dispatch ; the military strength and 
energy which result from these qualities of 
