823 / 1042
H Y D R
o
S T A T
e s.
bucK<t
G
a fcconJ time, the air betweeo it anu thewater
in the lower pipe at, wtll be agaioIcrt at libeny to Gil a
hrger fpace; and fa its fprlng bcing again weakencd. the
prelTure 'of [he outward air 00 tbe water in the velTtI
K
will force more water up into tbe lower pipefrom
e
to/;
¡nd I'Ihen the bucket is at its greatell heigbt
C.
thelower
.a1ve
b
will fall, and 1I0p the hale in the box H as
bé·
fore. At the OeKt lIroke of Ihe bucket or pilloo, the
W<Her will rife through the box
H
to.wards B, .ntl then
the .aIre
b,
IVhich was raifed by it, ",ill fall when lhe
bucket
G
is at
it~
gre¡tell height. Upon deprcfling the
bllckel agaio, the waler caOOOI be pufhed back through
the vall'e', which keeps clofe upoo the bale whilll the
pilloo defceods. And upon raiGog tbe pilloo agaio, the
outward prelTure of the ai r will force the waler up thro'
H, where it will raiCe the valve, aod follQw the bucket
to
C.
Upoo the Dext depreflion of the bucket
G,
it will
go dowo into tbe water inthe burel
B;
ando as the water
caonat bc driven back through the oow clofe valve
b.
it
will raife the valve
a
as the bucket deCceods, and will be
lifted up by tbe buckel wheo it is oext raiCed. And oow,
the whole Cpace below the buckct beiog full, tbe w.Her
above it canoot Gnk wheo it is oext deprelTed ; but upon
its depreflion, the valve
a
will rife to let the buckel
~o
dowo; aad wheo it is quite dowo, the valve
a
will fall
byits weight, and 1I0p the hale in the bucket. When
the bucket is oext " ifed, all the water above it will be
lifted up, aod begin to ruo off by the pipe
F.
And thus,
by raifing aod deprefliog lhe bucket alleroately, there i,
lIill more water raifed by it; which getting above the
pipe
F,
inlO the wide top
1,
will fupply the pipe, and
make it run witb a continued lIream.
So, al every lime the buckel is raifed, lhe valve
b
ri·
fes, aod the valve
a
falls: and at enry time tbe bu,ket
is deprelTed, the valve
b
falls, and
f1
rifes.
Asit is tbeprelTure of tbe airar atmofpberewbich caufe,
lhe water to rife and follow lhe pilloo or bucket
G
as it i.
drawn up; aod .fince a column of water
33
feet higb i,
of equal we;ghl with as lhick a column of the atmofphere
from the eanh to the very top of the air: therefore, the
perpeodicular height of the pillan or bucket from the furo
face of tbe water in tbe well mull always be lefs thao
33
Jeet; otberwife the water will never get above the
bucket. But, wheo lhe height is lefs, the prelTureof tbe
atmofphere will be greater thao the weight of the water
iD
thepump. and will therefore raife it above thebuckct ;
aod wheo tbe <Vater has once .got above tbe bucket. it
may be lifted thereby to any height, if the rod
D
be
roade long enough, aod a fu!licieot degree of nrength be
employed, la raife it with the weight of the water a·
bove tbe bucket; without eVer leogtheoiog the lIroke.
The force required to work a pump. will be as the
~eight
to which tbe water is raifed, aod as Ihe fquare of
lhe diameter of the' pump·bore, io lhat pan where the
pifiooworks. So Ihat, if two pumpsbe of equal heights,
and ooe of thcm be t\Vice as wide io the bore as the o·
tber. the widell will raife four times as much water as the
narrolVell
i
and will tberefore raquire four times as much
fireoglh 10 work it.
The widentfs or oarrownef, of the pump. io any other
pan herodes that io which the pinon works, does DOt
VOL .
n.
Numu,
60,
1
make the pump tither more or lefs diflicult 10 work; ex'
cept what diffaeoce mayarife fl om the fritlioo of Ihe
bure, \Vhich is always greater io a n"row bore thao
in
a
\Vide one, becaufe.
01
the greatcr vcloeity of Ihe wa–
ter.
T he pump·rod is nel'er raifed direélly by (ueh a han·
die as
E
al the 10p. but by means of a lever, whofe loo.
ger . rm (at the eod of which the power is applietl) ge.
oerally exeeeds the leogth
oC
lhe fborter arm five or ¡ix
times : aod, by tbat means, gives Gve or fi x times as
much advaotage to the pOlVcr. Upoo tltefe principies,
it will be eafy
10
hnd the dimeofioos of a pump tbat nlalI
work with a given force, and draw water from aoy gi.
ven depth. But, as thefe calculatioos have been gene·
rally negleéted by pump·makers (cither for \Vaot of lkilI
or iodullry) the followiog.table was caleulated by Ihe late
iogeoious Mr Booth for tbei r beoe61. lo tbis calcnlation,
he (uppofed the handle of the pump to be a lever iocrea·
fiog the power five times
j
and h.d ofteo fouod thal
a
man cao 1V0rk a pump four ioches diameter, aod
30
feet
high above the bucket. and difcharge
27~
galloos of
lVa·
ter (Eoglifh wine meafure) in a minute. Now, if it .be
required tofiod tbe diameter of a pump, that Ihall raife
water with the fam e eafe fromaoy other beigbl above tbe
bucket; luok for that heigbt in tbe firll columo, aDd o·
ver·againll it io the (ecoad you have tite diameler or widlh
of the pump ; and io the tbird, you fiod tbe quanlity of
water whicha ruaDof ordinary lIrength caodircharge io
a
minute.
-
Height of Ihe
I
Diameter of Ihe Water difch"ged
pump above
bore where the io a minute, Eng.
the bucket.
bucket works . Iifh ",ine· mea(ure.
"'1
.....
;;
C'l
"O
e
n
n
~
~.
~
:r
O
tl
'O
O'
a
;;:
----
------
lO
6
·93
BI 6
15
5 .65
54 4
20
4
.9
0
40
8
25
4
·3 B
3
2
6
30
4 .00
27 2
35
3 .70
23
3
40
3
'4 7
20
4
45
3
.26
lB
1
50
3
.10
16 3
Sí
2
·95
14
7
60
2
.83
13
5
65
2
·71
12 4
70
2
.62
11
5
75
2 ·53
10
7
80
2
'44
to
2
'{he [ orcil/g,/,nmp.
TI!
E
[ qrci"f Pu",/,
raifes water through the
bOl{
H
(fij¡.
4 )
in the fame m;!nner as Ihe fucking
pu.tI?do,;, when the
pluogcl' or pillun
g
is lif"d up by the
r~d
D,I.
IJIl I this
plunger I,as DO hale lhrough it, to let lhe waler in Ihe
t
B S
•
barrcl