■ 520 p 
liitj!, \\ hen atmospheric air containing a 
imxtuie ot it is breathed, it occasions a vio- 
ient and almost convulsive cough, attended 
with much pain in the chest. This cough 
usually continues to return at intervals for a 
day or two, and is accompanied with a co- 
pious expectoration. 
. ^ capable of supporting combustion; 
m man s c tses even more capable than com- 
mon air. When a burning taper is plunged 
into it, the flame is diminished, and acquires 
a v ei \ led colour; a great quantity of smoke 
is emitted, and at the same time the taper 
consumes much more rapidly than in com- 
mon air. I lie facility with which bodies 
take tire in this gas, seems to depend on the 
ease with which it parts with its oxygen. 
I nis gas is neither altered by exposure to 
light nor to caloric. It passes unaltered 
through red-hot porcelain tubes. 
It does not unite readily with water. 
Scheele found, that after standing 12 hours 
over water, four-fifths of the gas were ab- 
sorbed: the remainder was common air, 
which no doubt had been contained in the 
vessel before the operation. 
It renders vegetable colours white ; and not 
red, as other acids do ; and the colour thus 
destroyed can neither be restored by acids 
nor alkalies. It lias the same effects on yel- 
low wax. If the quantity of vegetable colours 
to which it is applied is sufficiently great, it 
is found reduced to the state of common mu- 
riatic acid. Hence it is evident, that it de- 
stroys these colours by communicating oxy- 
gen- Hhis property has rendered oxymu- 
riatic acid a very important article in bleach- 
ing. 
VI hen a mixture of oxymuriatic acid gas 
and hydrogen gas is made to pass through a 
red-hot porcelain tube, a violent detonation 
takes place. By electricity a feeble explo- 
sion is produced. 
When melted sulphur is plunged into it, 
inflammation also takes place, a'nd the sul- 
phur is converted into sulphuric acid; but 
•cold sulphur, though it is partly acidified by 
this g as, does not take fire in it. 
T> the fifteenth letter of the alphabet, as 
1 5 an abbreviature, stands for Publius, 
pondo, &c. ; PA. DIG. for patricia dignitas ; 
P. C. for patres conscript! ; P. F. for Publii 
Alius ; P. P. for propositum, or propositum 
publice; P. R. for populus Romanus ; PR.S. 
for praetoris sententia; and PRS. P. for prases 
provincial In the Italian music, P. stands for 
piano, or softly ; P.P. forpiu piano, i. e. more 
softly; and PPP. for pianissimo, or very soft- 
ly. Among astronomers, P. M. is used to 
denote post meridiem, or afternoon ; and 
sometimes for post mane, i. e. after midnight. 
As a numeral, P. signifies the same as G, 
viz. 400 ; and with a dash over it, thus G, 
400,000. Among physicians, P. denotes pu- 
gil or the eighth part of a handful; P. iE. 
p ■ ves cequales, or equal parts of the ingre- 
I’ M D 
Y\ lion phosphorus is plunged into this gas, 
it immediately takes fire, burns with consi- 
derable splendour, and is converted into 
phosphoric acid. 
Oxymuriatic acid oxidizes all the metals 
without the assistance of heat. Several of 
them take fire as soon as they come into con- 
tact with the gas. All that is necessary is, to 
throw a quantity of the metal reduced to a 
fine powder info a vessel filled with the gas. 
The inflammation takes place immediately; 
the metal is oxidized ; tv Idle the acid, decom- 
posed and reduced to common muriatic 
acid, combines with the oxide, and forms a 
muriat. Arsenic burns in oxymuriatic acid 
gas with a blue and green flame; bismuth, 
with a lively bluish flame; nickel, with a 
white flame, bordering on yellow; cobalt, 
with a white flame, approaching to blue; 
zinc, with a lively white flame; tin, with a 
feeble bluish flame; lead, with a sparkling 
white flame ; copper and iron, with a red 
flame. Several ot the metallic sulphurets, 
as cinnabar, realgar, sulphuret of antimony, 
take fire when thrown in powder into this 
When oxymuriatic add gas and ammoniacal 
gas are mixed together, a rapid combustion, 
attended with a white flame, instantly takes 
place ; both the gases are decomposed, wa- 
ter is formed, while azotic gas and muriatic 
acid are evolved. The same phenomena are 
apparent, though in a smaller degree, when 
liquid ammonia is poured into the acid gas. 
The same decomposition takes place, though 
both the acid and alkali are in a liquid state. 
If four-fifths of a glass tube are filled with oxy- 
muriatic acid, and the remaining fifth with 
ammonia, and the tube is then inverted over 
water, an effervescence ensues, and azotic 
gas is extricated. It was by a similar expe- 
riment that Berthollet demonstrated the com- 
position of ammonia. 
Oxymuriatic acid is composed of 
84 muriatic acid 
16 oxygen 
100 . 
P 
PACE, passus, a measure taken from the 
space between the two feet of a man in 
walking ; usually reckoned two feet and a 
half, and in some men a yard or three feet. 
The geometrical pace is five feet ; and 
60,000 such paces make one degree of the 
equator. 
PACK, in commerce, denotes a quantity 
of goods, made up in loads or bales for car- 
riage. A pack of wool is 1 7 stone and two 
pounds, ora horse’s load. 
PACKERS, persons whose employment it 
is to pack up all goods intended for exporta- 
tion ; which they do for the great trading 
companies and merchants of London, and are 
answerable if the goods receive any damage 
through bad package. 
PACOS. See Camelus. 
P.EDERIA, a genus of the pentandria 
P M O 
Though oxymuriatic acid has hitherto been 
placed among acids by chemists, it does not 
possess a single property which characterises 
that class of bodies. Its taste is not acid but 
astringent ; it does not convert vegetable 
blues to red, but destroys them; it combines 
very sparingly with water, and is incapable 
of combining with alkalies,- earths, or metal- 
lic oxides. It-Ought, therefore, to be placed 
among the oxides rather than the acids. 
Oh ER of deed, is when a man brings 
an action upon a deed, bond, &c. and the 
defendant appears and prays that he may 
hear the bond, &c. w herewith he is charged, 
and the same shall be allowed him: and he is 
not bound to plead till he has it, paying for 
the copy of it. 
The time allowed for the plaintiff to give 
oyer of a deed, &c. to the defendant, is two 
days exclusive after it is demanded. Carth. 
454. 2 Durnf. & East, 40. 
Oyer and terminer, is a court held by- 
virtue of the king’s commission, to hear and 
determine all treasons, felonies, and misde- 
meanors. This commission is usually di- 
rected to two of the judges of the circuit, and 
several gentlemen of the county ; but the 
judges only are of the quorum, "so that the 
rest cannot act without them. 4 Black. 26y. 
See Assizes. 
OYES, or Oyez, signifies hear ye; and 
is frequently used by the cryers in our courts 
on making proclamation, or to enjoin si- 
lence. 
OYSTER. See Ostrea. 
OZiENA, a malignant ulcer of the nose, 
frequently accompanied with a caries of ail 
the bones of that part. See Surgery. 
OZOPHYLLUM, a genus of the class and 
order monadelphia pentandria. It is one- 
styled; calyx five-toothed ; petals five, long ; 
filaments sheathing; the style five-toothed at 
top ; teeth anheriferous ; stigma one ; cap- 
sules five-celled. There is one species, a 
native of Guiana. 
monogynia class and order. It is contorted ; 
berry void, brittle, two-seeded; style bifid. 
I here are two species, climbers of the East 
Indies. 
PvEDEROTA, a genus of the monogynia 
order, in the pentandria class of plants^ and 
in the natural method ranking under the 30th 
order,- contort*. The berry is empty, brittle, 
and dispermous; the style' bilid. There are 
three species. 
P/EONIA, peon//, a genus of the digynia 
order, in the poly and ria class of plants, and 
in the natural method ranking under the 26th 
order, miiltisiliquae, The calyx is penta- 
phyllous ; the petals five ; there are no styles ; 
the capsules are polyspermous. There are 
five species, most of them hardy. They are 
large herbaceous flowery perennials, with 
tuberous roots, sending up strong annual 
