IMP 
IMP 
alcohol and water; the same also obtains 
when we mingle, by fusion, copper with 
zinc, in order to form the compound metal 
called brass : it is then observed that the 
density of the mixture is augmented by 
about its tenth part. This apparent pene- 
tration is owing to the circumstance that 
the moleculae of the two bodies, in conse- 
quence of their respective formation, gene- 
rally approach one another more than in jhe 
two bodies taken separately : there hence 
results, in the figure of the pores, such a 
change as diminishes' the space equal to the 
sum of these pores. On the contrary, in 
the alloy of silver with copper, a kind of 
rarefaction is produced, such that the 
volume of the mixture is larger than the 
sum of the volumes of the two bodies, 
previous to fusion. 
IMPERATIVE, one of the moods of a 
verb, used when we would command, en- 
treat, or advise : thus, go, read, take pity , 
be advised , are imperatives in our lan- 
guage. 
IMPERATORIA, in botany, a genus of 
the Pentandria Digynia class and order. 
Natural order of Umbellatas, or Umbelli- 
ferae. Essential character: fruit roundish, 
compressed, gibbose in the middle, sur- 
rounded by a margin ; petals inflex, emar- 
ginate. There is but one species, viz. I. 
ostruthium, master-wort, the root of which 
is thick, running obliquely in the ground ; it 
is fleshy, aromatic, and has a strong acrid 
taste, biting the tongue and mouth; the 
leaves arise immediately from the root, hav- 
ing foot-stalks seven inches long, divided 
into three very short ones at the top, each 
sustaining a trilobate leaf, indented on the 
border; the foot stalks are deeply channel- 
ed, and when broken emit a rank odour ; 
the flower-stalks rise two feet high, dividing 
into two or three branches, each terminated 
by a pretty large umbel of white flowers, 
whose petals are split ; these are succeeded 
by oval compressed seeds, resembling those 
of dill, but larger. Linnaeus observes, that 
the floral leaves are opposite, that there is 
a petiolary, membranaceous, ventricose, 
stipule, one'within another. It is a native 
of many parts of the Alps, Austria, Syria, 
Tyrol, Silesia, and Dauphine. 
IMPERFECT, something that is defec- 
tive, or that wauts some of the properties 
found in other beings of the same kind : 
thus mosses are called imperfect plants, be- 
cause almost all the parts of fructification 
are wanting in them; and for the like reason 
is the appellation imperfect given to the 
fungi and submarine plants. 
Imperfect numbers, such whose aliquot 
parts taken together do either exceed, or 
fall short of that whole number of which 
they are j *. rts : they are either abundant or 
deficient. Thus 12 is an abundant imper- 
fect number, because the sum of its parts 
1 — }— 2 — 3 — 4 — <3 = 16, which is greater 
than 12. But 10 is a deficient imperfect 
number, because 1 — {- 2 — j— S = 8 only, 
which is less than 10. 
IMPERSONAL verb, in grammar, a 
verb to which the nominative of any certain 
person cannot be prefixed ; or, as others 
define it, a verb destitute of the two first 
and primary persons. 
IMPETIGENES, in medicine, descrip- 
tive of those disorders which, from a gene- 
ral bad habit, manifest themselves princi- 
pally by disfiguring the skin and external 
parts of the body. 
IMPETUS, in mechanics, the force with 
which one body impels or strikes another. 
IMPLEAD, to sue or prosecute by 
course of law. 
IMPLICATION, in law, is where the 
law implies something that is not declared 
between parties in their deeds and agree- 
ments, and when our law gives any thing to 
a man, it gives by implication whatever is 
necessary for enjoying it. An implied con- 
tract is such, where the terms of agreement 
are not expressly set forth in words, but are 
such as reason and justice dictate, and 
which therefore the law presumes that every 
man undertakes to perform. Estates often 
arise by implication in a will, and sometimes 
in a deed ; but they are more readily im- 
plied in the former than in the latter in 
which the words must be more strict. 
IMPONDERABLE substances. See 
Substances, imponderable. 
IMPORTATION, the act of bringing 
goods into a country from foreign parts. 
It has generally been considered, that for 
any country to carry on a profitable trade, 
it is necessary that the value of the goods 
sent out of it should be greater than that 
of the articles imported ; this, however, is a 
very erroneous axiom, unless it is under- 
stood with great limitations. All articles 
of merchandize, imported merely for re- 
exportation, and also such as are used or 
worked up in our own manufactures, are 
far from being hurtful to onr commerce, and 
may even, in many respects, be deemed of 
equal profit with our own native commodi- 
