557 / 868
P L U
is Ict to
r.::n,
;.n.:l the exaél: poiat
wncre
il
rcfh
is markcd
with
a ven:
ht; Ihc:o goes
0 0
f" rthef in the line Udl fallen·
eJ, and a. th'!
n c XI
flexure
or
toe adi l he makes a mark
on the lioe
by
a knot or
ot herwir~;
and then lt:tling clown
the di.!.!
a¡;din,
'he there l.kewife
nOtes
down t hat poi nt a!
which Ihe nccJlc It.lnds in this [ecund pofilion.
[o chis
m. nner he proceeds, from turni ng
10 lu rning.
m;ukinc
do",,'" thc:
POil"ltS,
¿nd mai king the li ne,
tiJl
he comes
10
the intl!odcd place :
chis
dune, he
arC~nd5J
and btgins to
wo:k on
th~
furface of the
eilnh
wh~t
he did in Ihe adit,
hri nging che fi rrt knot in the
lioe
10
fuch
a
p)..tce .wl~e re
Ihe ol.lrk of
th~
place of Ihe need le \1,:11 2gain
anr~ver
its
pvint ing. and continues this till he come
10
the defired
p1:tce above
ground,
which is cen ai n
lO
be
perpe~ld!cu~
hrl y
over
the
pan
of
the mine into
which
th~
airJ1Hrt is
' o
be fu roL
PLUMOSE , fJ me,hing formed in ,he m' nner or.. fe . ther,
p
N
E
u
M
T
HIS
fl:ienee
treats of
(he
nature,
weigtlt ,
and prdfure
of the
air,
and
tne effl'tls
arifin g
from
it.
T he
air
is
th.ttthin
trd.nfpdreot
fluid body in which
we
Jíve
and
breal he ...
lt
encompJffcs
thl! wholc
earth to a conu·
dcrablt!
hei~h t
j
and o
tOgether
wirh
the cloud:; and
vapours
lh t O, . , in it, is ealled ,he .. mofphere. T he .ir is j "íJly
recko.1ed
among lhe number of 8
.ids,
becaufe
it has a1l the
propen ies by which • fl uid is dillinguirn, d . (See HVOR O–
ST AT' CS .)
For i, yiel'ds tO ,he le"(\ force impieffod, its
pans are eafily moved amoog one another,
it
prdf: s ac–
lording
tO
in perpendicular
height,
and
its
prdrure is
every
", .yequal.
11lat
the
air
is
a
fluid,
confifiing of fuch pan iclcs a,
h:\\'e
na
cohdio~
belwixt
Ihem ,
bUl eafily
glidl! over one another,
4ind yieJd to
lhe
Oighteft impreffion ,
appe4.rsfrom
th:ll
eafe
and
freedoól with
which aniOlals
breathl!
iD
il. and move
th ro"gh
it
wi,hoUl.• ny diílieulty or fenGble
reGHar.ce.
Bo, il.d;(fe" frottl . 11 o ,her flo ids in Ihe th ree following
r aniculars . 1t
can
be
eomprelTcrl
¡nlo
a
lefs fpace
lhí\n
what
. ic naluraliy poffeffeth.
~hich
no olher fl uid
call .
2.
h
can~
not
be congeaJed or fiKCd,
as
other
fl uid s
mayo
3. It
is
or
a
difFc:renl
denfi ty
in
every
part,
upwai"d
from lhe
ean h's
Cur~
l¡tce, deerealing
i~
in
weight. bulk
for bulk, the
higher ít
r ifes; and theref" re
m~(l
al lo deere. fe inden fi, y. 4 ..
lt
is of
án
elaClic
or
Cpringy
nature,
and
the force of ilS
Cpríng
is e·
q ual lO
jn
weight.
Th:n air
is
a
b ody,
is evi": ent from
¡ts
exelud¡"'
hg all oTher
)jodies out of ,he fpaee it poff, ffcs ¡ for, if .
gl.fs· jar be
plcnged
wi th it; mOlHh
tlownward
iuto a
vd fel
of
water,
tliere
will bUI very
little
waler gel iOlO
the
jar: becaufe
the
air of
",hieh
it
is
full
keeps Ihe waler out
. As air is a
bod y, ir
mua
needs
ryOlve
gra \·ity or weight
f
~nd
lhu
it
i,
weighty.
i,
demonflr,lIed
by
expt:riment.
For,
Jet .he air be
ukf!n
om of a veffd
by
means of
the
air-pump ;
, henoha, ing
wei~hcd
the
vecrel, let in
Ihe
:lir
ag~in ;
and
upon
w('i~:h i ng
it,
when
rc-.filJed
Wilh
airo it \ViII be found
¿onfidtíaL.'y
h~.t9ier ,
Th'.ls,
a botde lhat
holds
a wine
qu<t rt,
b~i ng
emptjcd
of
::ir,
and
wcigh ~d.
is f'ou nu lobe a:–
b-;"Ul
1,7
grains
li~h t<.r
lhao
when lhe ai r is I:!l i:lloit 3&1io ;
"...,hit:h Ih,;V/s
tI..
"t
a
cpprt
of
eir
weighs 17 graios.
Dut
a 'lUlrt of W,ler
wc:~hs
14625 s raios ; ,his diviJed by
lo
P L U
wilh
a (l e;n
and libres
ifT'uing
from
ir
on each
{ice
~
fuch
are (he antenoa: of certain
mOlhs, bUHerfiies,
&e,
PLURA
r.,
in brammt\ r, an
epi lhel
;:¡ pplied
to
th;u ncmb<r
"f
nouns
and
verl s
which is uli:d
when
w:
fpeak of more
Ih.lOune
thing. See
GRAto1MAR.
PLURALI T Y. • difere,e 'Iu.n,i,y, co"r,Oi ng of
,\vo
or a
greatt r
number
o" tbe folme kind
j
Ihus
w t:
fay
a pluralilY
of gods,
&c.
PLUS, in . Igebra,
a
eh.r.n"
mar~ed
,hu.
+,
ufed for the
lign of addi,ion.
PLUSH, in eommeree,
&f . •
kind ¡'f ¡¡ uff
h..
ing
a
for'
of velve, kn.p, or (h' g. on on< fid e, compo(cd regul.r1y
of a woof of a
(jr~le
wooleo
thread, and "
double \V2rp;
the
One
w.)o!, of
l WO
thre:\ds twifted;
lhe other
goals or
cltmcls h3ir;
though there
are fome plllfhes
emir ely
of
worf!ed.
, ñ:l
o,h~rs
eo:npofed wholly of hair.
PLUVfALIS , in zoology. See eH'ARAD RI vs .
A
' l .
e s.
t
7.
quotrs 860
in
round
numbers; whirh
fh ews,
Ihal
water is 860
times as
bea\'y
as
¡ir
oear
lhe
fu rface
of the
earth .
As
lhe ai r rifeS above
the eatth's
fu rfaee.
ir gro\\'S ra·
rer,
.n~
eonf<qllentfy lighter, bulk for bu'k . F or r,nee i, i'
of
a.n e);t[tic
or
fpringy nature, and
¡es
lowe rmo(l part! are
prdTed
with the- weight
ofi all
thJt
is abo\'e them. il is
plain
tirat the
ai r
muH
be
mere
den
fe or comp
\ét
at
<{he earl h's
fu rface, than at any height above
it;
and
graduaJly raler
,he higher up. F or, the denfi,y of ,he . ir is alw. ys "
the
force Ih"t
comprelrelh
it :
and
thercfore ,
lhe
¡ir
te·
wards
the u'pper
pa ru
of
lhe atmo(phere beir.g ters pre(s.
ed
th.m th,il
'w hict\
is
near lhe eanh ,
it
will
expl od ¡Ifelf,
and thereby
become
IhinnN lhao
al
the (uTface of lhe earlh.
Dr
Cotes
h3S demonnrated, tbat
if
altitudes in'
the
Olit
b'!
taken
in arithmc[icdl
propon ion,
~rhe
rarity of tb: air
will be in
geometricd.1 proponion,
For ¡nnance,
r
71
~
(
.
41
I
~ ~'¡:i
l . ..
~~
\
u
28
1
-5
I
.
25 6
1-=
'\ 35
•
10 2
4
"
4
2
-5"
I
.
4
0
9 6
1
~
t...
49
E
.
r638 tl
-=
:
56 1
u
•
65 536 1'
t
~
:...
~~_
63
~
I
262 1-1 4
~~
=
70
o
10485i6 ¡:'=:2
77
r
~ ~
4
1
9 43°4
2! .~
-5
84
~
I
167772 16
~ ~
<
9 1 2 ,
.
67 108 864 1
~~
\ 98 1-5 \
268
43545 6
:a
. ' 05
u .
10
7374 182
4 -
l
it
2
:;
I
42 94~67 2'16 1 ~
11 9 \
~
17' 79
86 9,84
·5
126. ::
6 8 7
194i 6 73 6 \
1 3 ~
I '§
2H S 7790 6 9 44
ll 40 )
L
1° 99 5
11 62
777
6 )
Ana
hene\!
it
is eafy
tO
prove
by
calcul.u ion, rh;¡ t a ell"
bic ineh of fu eh air as we brealhe, wOll ld be
fa
much
riHe–
fied
2'
,he alt;tude of 500 miles. th. t il " ould !ill a Ir- her •
t'l"' !
io di. meter to ,he orbit
o~Sa'urn.
Th: