PIT 
PIS 
aosje. Essential character : stigma acute; 
legume winged four ways. There are two 
species, lAz. P. erythrina, Jamaica dog- 
wood tree, and P. carthaginensis, both na- 
tives of the AVest Indies. 
PISCIS australis, the southern fish, is a 
constellation in the southern hemisphere, 
being one of the forty-eight constellations 
mentioned by the ancients. The Star toma- 
faaut, of the first magnitude, is in the mouth 
of this fish. PLscis volans, the flying fish, 
a small constellation of th? southern he- 
niisphere, added by the moderns : it con- 
tains eight stars, but is not visible in our 
latitude. 
PISONIA, in botany, so named in ho- 
nour of AVilliam Piso, a physician, a genus 
of the Polygamia Dioecia class and order. 
Natural order of Nyctagines, Jussieu. Es- 
sential character : calyx scarcely any ; co- 
rolla bell shaped, five-cleft ; stamina five or 
six ; pistil one ; capsule superior, one-celled, 
valveless : male and female on the same or 
on ditferent plants. There are five species. 
PISTACIA, in botany, a genus of the 
Dioecia Pentandria class and order. Na- 
tural order of Amentaceae. Terebintaceae, 
Jussieu. Essential character: male an 
ament; calyx five-cleft; corolla none; fe- 
male distinct ; calyx trifid ; corolla none ; 
styles two ; drupe one-seeded. There are 
six species, among which we shall notice 
the P. lentiscus, mastick tree ; it is about 
eighteen or twenty feet in height, the 
trunk is covered with a greyish bark, the 
branches are numerous, the leaves have 
three or four pairs of small leaflets, of a 
lucid green on their upper, but pale on their 
under side ; the male flowers come out in 
loose clusters from the sides of the branches, 
of an herbaceous colour, appearing in May, 
and soon falling off ; they are generally on 
different plants from the fruits, which also 
grow in clusters, and are small berries of a 
black colour when ripe. 
PISTAZITE, in mineralogy,' is of pista- 
chio green, passing sometimes into olive 
green, and blackish green. It occurs mas- 
sive and crystallized. Internally it is shin- 
ing; fracture sometimes foliated, some- 
times narrow, parallel and stellular, diverg- 
ing radiated. It is hard, easily frangible, 
and not very heavy. It occurs in beds in 
primitive mountains in Norway, Germany, 
and France. 
PISTIA, in botany, a genus of the Mo- 
nadelpliia Octandria class and order. Na- 
tural order of Miscellaneae. Hydrochari- 
des, Jussieu. Essential character: calyx 
none; corolla one-petalled, tongue-shaped, 
entire ; anthers six or eight, placed on the 
filament ; style one ; capsule one-celled at 
tlie bottom of the corolla. There is but 
one species, viz. P. stratiotes, a native of 
Asia, Africa, and South America, in stag- 
nant waters. 
PISTILLA, in botany. See Botany. 
PISTOLE, a gold coin struck in Spain, 
and in several parts of Italy, Switzerland; 
&c. equal to about ten shillings and six- 
pence of our money. 
PISTON, in pump-work, is a short cy- 
linder of metal, or other solid substance, 
fitted exactly to the cavity of the barrel or 
body of the pump. There are two kinds of 
pistons used in pumps, the one with a valve, 
and the other without a valve, called a forcer. 
PISUM, in botany, pea, a genus of the 
Diadelphia Decandria class and order. 
Natural order of Papilionaceae, or Legumi- 
nosae. Essential character: style triangu- 
lar, above keeled, pubescent ; calyx has the 
two upper segments shorter. There are 
three species, of which we shall mention 
P. sativum, the common pea. Many vari- 
eties of this are cultivated in England; 
the Hotspurs and Hastings have their names 
from their coming to bear early in the sea- 
son ; new varieties of these are raised al- 
most every year, which, because they differ 
in some slight particular, are sold at an ad- 
vanced price, having frequently the names 
of the persons w'ho raised them, or the 
place where they first grew. These varie- 
ties are not permanent, and, 'without the 
greatest care, will soon degenerate. 
PITCAIRNIA, in botany, a genus of 
the Hexandria Monogynia class and order. 
Natural order of Coronarise. BromeUae, 
Jussieu. Essential character : calyx three- 
leaved or three-parted, half superior; co- 
rolla three-petalled, with a scale at the base 
of each petal ; stigmas three, contorted ; 
capsule three, opening inwards ; seeds 
wdnged. There are three species, natives 
of the AA'est Indies. 
PITCH, a tenacious oily substance, 
drawn chiefly from pines and firs, and used 
in shipping, medicine, and various other 
arts : or it is more properly tar, inspissated 
by boiling it over a slow fire. The method 
of procuring the tar, is by cleaving the trees 
into small billets, which are laid in a furnace 
that has two apertures, through one of 
which the fire is put, and through the other 
the pitch is gathered, which, oozing from 
the wood, runs along the bottom of the 
furnace into places made to receive it. 
