P L E 
P L E 
45 2 P L A 
L • It combines with most of the metals, 
and forms alloys. 
W hen gold and platinum are exposed to a 
strong heat, they combine, and form an alloy 
ot gold and platinum. It the platinum ex- j 
ceeds _A_ of the gold, the colour of the alloy j 
is much paler than gold; but if it is under! 
TT’ ^ ie co ' olu ' °f the gold is not sensibly i 
altered. Neither is there any alteration in! 
the ductility of the gold. Platinum may be 
alloyed with a considerable proportion of 
gold, without sensibly altering its colour. 
VI. The affinities of platinum are at pre- ; 
sent unknown. It this metal could be ob- 
tained at a cheap rate, it would furnish very 
useful vessels, that might be exposed to the 
greatest heat without alteration. 
PLATONIC year, or the great year, ! 
is a period of time determined by the revo- 
lution of the equinoxes, or the space wherein 
the stars and constellations return to their 
former places in respect of the equinoxes. 
The Platonic year, according to Tycho 
Brahe, is 25810, according to Ricciolus 
25920, and according to Cassini 24800 years. 
PLATOON, in the military art, a small 
square body of forty or fifty men, drawn out 
of a battalion of foot, and placed between the 
squadrons of horse, to sustain them; or in 
ambuscades, straits, and defiles, where 
there is not room for whole battalions or re- i 
giments. Platoons are also used when they 
form the hollow square, to strengthen the 
angles. The grenadiers are generally posted 
in platoons. 
PLATYLOBIUM, a genus of the diadel- j 
phia decandria class and order. The calyx 
is bell-shaped, five-cleft ; the two upper seg- j 
ments very large; legume pedicelled, com- ! 
pressed, winged at the back. There is one ! 
species, a shrub of South Wales. 
PLATYPUS, a quadruped of the order; 
of bruta. The generic character is, mouth ! 
shaped like the bill of a duck ; feet webbed, i 
Of this extraordinary genus two specimens 
have been sent from New Holland to sir 
Joseph Banks by governor Hunter. 
Of all the mammalia yet known, this seems 
the most extraordinary in its conformation ; 
exhibiting the perfect resemblance of the beak 
of a duck engrafted on the head of a quadru- ; 
ped. So accurate is the similitude, that, at I 
first view, it naturally excites the idea of i 
some deceptive preparation by artificial I 
means ; the very epidermis, proportion, ser- 
ratures, manner of opening, and other par- 
ticulars of the beak of a shoveler, or other 
broad-billed species of duck, presenting them- ! 
selves to the view : nor is it without the most 
minute and rigid examination that we can 
persuade ourselves of its being the real beak 
or snout of a quadruped. 
The body is depressed, and lias some re- ■ 
semblance to that of an otter in miniature. 
It is covered with a very thick, soft, and 
beaver-like fur, and is of a moderately dark 
brown above, and of a subferruginous white 
beneath. The head is tlattish, and rather 
small than large; the mouth or snout, as be- 
fore observed, so exactly resembles that of 
some broad-billed species of duck, that it 
might be mistaken for such : round the base 
is a flat circular membrane, somewhat deeper 
or wide r below than above, viz. below nearly 
the fifth of an inch, and above about an 
..eighth. The tail is fiat, furry like the body, 
rather short and obtuse, with an almost bifid 
termination ; it is broader at the base, and 
gradually lessens to the tip, and is about 
three inches in length; its colour is similar 
to that of the body. The length of the whole 
animal from the tip of the beak to that of the 
tail is i3 inches; of the beak an inch and a 
halt. 1 he legs are very short, terminating 
in a broad web, which on the fore feet ex- 
tends to a considerable distance beyond the 
claws; but on the hind-feet reaches no far- 
ther than the roots of the daws. On the 
fore-feet are five claws, straight, strong, and 
sharp-pointed ; the two exterior ones some- 
what sho.ter than the three middle ones. On 
the lnnd-leet are six claws, longer and more 
inclining to a curved form than those on the 
fore-feet ; the exterior toe and claw are con- 
siderably shorter than the four middle ones; 
the interior or sixth is seated much higher up 
than the rest, and resembles a strong sharp 
spur. All the legs are hairy above; the fore- 
feet are naked both above and below ; but 
the hind-feet are hairy above, and naked be- 
low. The internal edges of the under man- 
dible (which is narrower than the upper) are 
serrated or channeled with numerous stria?, 
as in a duck's bill. The nostrils are small 
and round, and are situated about a quarter 
of an inch from the tip of the bill, and are 
about the eighth of an inch distant from each 
other. There is no appearance of teeth; the 
palate is removed, but seems to have resem- 
bled that of a duck; the tongue also is want- 
ing in the specimen. Tie ears, or auditory 
foramina, are placed about an inch beyond 
the eyes; they appear like a pair of' oval 
holes, of the eighth of an inch in diameter, 
there being no external ear. On the upper 
part of the head, on each side, a little beyond 
the beak, are situated two smallish oval white 
spots : in the lower part of each of which are 
imbedded the eyes, or at least the parts allot- 
ted to the animal for some kind of vision ; 
for from the thickness of the fur, and the 
smallness of the organs, they seem to have 
been but obscurely calculated for distinct vi- 
sion, and are probably like those of moles, 
and some other animals of that tribe ; or per- 
haps even subcutaneous ; the whole apparent 
diameter of the cavity in which they were 
placed not exceeding the tenth of an inch. 
When we consider the gener. 1 form of this 
animal, and particularly its bill and webbed 
b et, we shall readily perceive that it must be 
a resident in watery situations ; that it has the 
habits of digging or burrowing in the bank's 
of rivers or under ground; and that its food 
consists of aquatic plants and animals. This 
is all that can at present be reasonably guessed 
at: future observations, made in its native 
regions, will, it is hoped, afford us more 
ample information, and will make us fully 
acquainted with the natural history of an ani- 
mal which differs so widely from all other 
quadrupeds, and which verifies, in a most 
striking manner, the observation of Butfon, 
viz. that whatever was possible for nature to 
produce, has actually been produced. 
The platypus is a native of Australasia or 
New Holland. 
PLExA that which either party alleges for 
himself in court. These are divided into 
pleas of the crown and common pleas. 
Pleas of the crown are all suits in the king’s 
name, against offences committed against his 
! crown and dignity, or against fiis grown and 
peace. Common pleas are those that are 
held between common persons. • 
Common pleas are either dilatory, or pleas 
to the action. 
Pleas dilatory are such as tend merely to 
delay or put off the suit, by questioning the 
propriety of the remedy rather than by de- 
nying the injury. 
Pleas to the action are such as dispute the 
very cause of suit. 3 Black. 301. See Tidd’s 
K. 15. Practice. 
PLEADINGS, in general, signify the al- 
legations of parties to suits when they are 
put into a proper and legal form; and are 
distinguished in respect to the parties who- 
plead them, by the names of bars, replica- 
tions, rejoinders, sur-rejoinders, rebutters, 
sur-rebutters, &c. and though the matter in 
the declaration of court does not properly 
come under the name of pleading, ye , being 
often comprehended in the extended sense 
of the word, it is generally considered under 
this head. See Tidd’s K. B. Practice. 
PLEBISCITUM, in Roman antiquity, a 
law enacted by the common people, at the 
request of the tribune, or other plebeian ma- 
gistrate, without the intervention of the se- 
nate. 
PLECTRANTHUS, a genus of the gym- 
nospermia order, in the didynamia class of 
plants, and in the natural method ranking 
under the 42d order, verticil latas. The calyx 
is monopbyllous, short, and biiabiated ; the 
upper lip oi which is large, oval, and bent 
upwards ; the inferior lip is quadrifid, and 
divided into two lacunae: the corolla is mo- 
nopetalous, ringent, and turned back ; the 
labia: look different ways, and from the base 
of the tube, there is a nectarium like a spur : 
the .filjfhients are in a declining situation, 
with simple antherae : the stylus filiform ; the- 
stigma bifid. It has four seeds, covered only 
by the calyx. There are five species: the 
fruticosus is a native of the Cape of Good 
Hope ; the punctatus is a native of Africa. 
The first flowers from June to September, 
the latter from January to May. 
PLECTROMIA, a genus of the class and 
order pentandria monogynia. The petals arb 
five; berry two-seeded, inferior. There is 
one species, a tree of the Cape. • 
PLEIADES, in astronomy, an assemblage- 
of stars m the neck of the constellation Tau- 
rus. See Astronomy. 
PLENE ADMINISTRAVIT, a plea 
pleaded by an executor or administrator, 
where they have administered the deceased’s 
estate faithfully and justly before the action 
brought against them. 
PLENUM, in physics, denotes, according 
to the Cartesians, that state of things wherein 
every part of space is supposed to be full of 
matter; in opposition to a vacuum. 
PLENUS FLOS. See Botany, Vol. I, 
p. 251. 
PLETHORA. See Medicine. 
PLEURA. See Anatomy. 
PLEURISY. See Medicine. 
PLEURONEC 1 ES , flounder, a genus of 
fishes of the order thoracici, of which there 
are 17 species. The generic character is, 
eyes both on tiie same side ot the head ; body 
compressed, one side representing the back, 
and the other the abdomen. 
The singular structure of this genus is justly 
considered as one oi the most curious devia- 
3 
