IMP 
conies very branching. Mr. Millar tells us 
he lias seen the stem seven inches in circuit, 
and all the plants large in proportion, 
branched from top to bottom, loaded with 
its party-coloured flowers, thus forming a 
most beautiful bush. The varieties which 
cultivation has produced in this elegant 
flower are numerous. 
I. noli tangere, common yellow balsam, 
is also an annual plant ; during the day the 
leaves are expanded, but at night they hang 
pendant, contrary to what is observed in 
most plants, which from a deficiency of 
moisture, or a too great perspiration from 
heat, commonly droop their leaves in the 
day-time. When the seeds are ripe, upon 
touching the capsule they are thrown out 
with considerable force : hence the Latin 
name “ impatiens” and “ noli tangere" The 
whole plant is considerably acrid, and no 
quadiuped, except perhaps the goat, will 
eat it. 
IMPEACHMENT, is the accusation 
and prosecution of a person in parliament, 
for treason, or other crime and misdemea- 
nors. An impeachment, before the Lords, 
by the Commons of Great Britain, is a pre- 
sentment to the most high and supreme 
court of criminal jurisdiction, by the most 
solemn grand inquest of the whole kingdom. 
A commoner cannot be impeached before 
the lords for any capital offence, but only 
for high misdemeanors ; but a peer may be 
impeached for any crime. The articles of 
impeachment are a kind of bills of indict- 
ment, found by the house of commons, and 
afterwards tried by the lords, who are, in 
cases of misdemeanors, considered not only 
as their own peers, but as the peers of the 
whole nation. By stat. 12 and 13 Wm. c. 2. 
no pardon under the great seal, shall be 
pleadable to an impeachment by the com- 
mons in parliament ; but the king may 
pardon after conviction. 
Impeachment of waste, signifies a re- 
straint from committing of waste upon lands 
and tenements ; and therefore he that has 
a lease without impeachment of waste, has 
by that a property or interest given him in 
the houses and trees, and may make waste 
in them without being impeached for it, 
that is, without being questioned, or de- 
manded any recompense for the waste 
done. 
IMPEDIMENTS, in law, persons un- 
der impediments are those within age, un- 
der coverture, non compos mentis, in prison, 
or beyond seas : who by saving in our laws, 
have time to claim and prosecute the right, 
IMP 
after the impediments removed, in case of 
fines levied, & c. 
IMPENETRABILITY, in philosophy, 
that property of body, whereby it cannot 
be pierced by another : thus, a body, which 
so tills a space as to exclude all others, is 
said to be impenetrable. Or, by impene- 
trability is meant the faculty which a body 
has of excluding every other body from 
the place that it occupies, in such man- 
ner that two bodies placed in contact can 
never occupy less space than that which 
they filled when they were separate. The 
impenetrability of solid bodies does not 
require to be proved, it strikes us at first 
view ; but fluids, having their particles 
perfectly moveable in every direction, and 
yielding to the slightest pressure, their im- 
penetrability does not manifest itself so per- 
ceptibly as that of solid bodies. Taking 
the air for an example : so long as this fluid 
is not enclosed in something, its extreme 
mobility causes it to admit a free passage 
to all bodies which are moved through it;, 
but in this case it is properly displaced, and 
not penetrated ; for, if the air be included 
within the sides of a vessel, and another 
body be then presented to take its place, 
without suffering it to escape, it will exer- 
cise its impenetrability in the same manner 
as solid bodies. It is easy to be convinced 
of this by the aid of a very simple experi- 
ment, which any cne may make : it consists 
in plunging a vessel vertically, with the ori- 
fice downwards, in another vessel filled with 
water to a certain height : the surface of 
the water corresponding with the orifice of 
the first vessel, is depressed as this vessel 
itself descends; and this depression may be 
rendered more sensible by means of a little 
plate, or slip of cork, placed so as to float 
upon the surface of the water ; nevertheless 
this water is not excluded by the air occu- 
pying the immersed vessel ; it is always 
raised within it by a certain quantity, which 
augments as the vessel is immersed to a 
greater depth : but it is sufficiently evident 
that this ascension is occasioned by the 
circumstance that the air is a compressible 
fluid, and therefore its volume is contracted 
into a smaller space, by the effect of the 
compression excited upon it by the sur- 
rounding water on all parts, in virtue of its 
weight. We must here notice a difficulty 
which appears to result from this, that when 
we have mingled certain bodies, the volume 
of the mixture is less than the sum of the 
volumes taken separately. This happens, 
for example, when we mix equal parts ef 
