65 / 868
5°
M
E
e
H
will
rcquire a third pan of more power to work them
when loade:d, than wh:a is fufficient to conel!tute a
ba~
JaDee
between tbe weight and the
power.
Of lI!illl, erano, Whul carriogo, and ¡he EI/gine far
driving Pilo.
As there machines are fa univerfally uferul, it
wo~ld
be ridieulous tO
m.keaoy .pology for deferibiog them.
lo a eommon
hrtajl.mill,
where the fall of water may
be
about tea feet, AA (Plate CVIII. fig.
9.)
is the great
wheel, which is generalJy about 17 or 18
[eel
in
diameler,
teekooed from the outermo(l edge of any Roat·board at
a
tO
that of its oppofite
/loal al
b.
To
this
wheel the
\vater
is
eooveyed through a chao
Del ;
aod fa, falliog upoo ,he
wheel, turns
it
round.
On ,he axis
BB
of ,hi. wheel, and within ,he mili·
houfe, is a wheel D , about 8 or 9
[eel
diameter, having
61
cogs,
which turo a tatndle E containing ten upright
llaves or raunas; and wheo thefe are
~
number of cogs
aDd rounds, the trundle wiII make
6)10)'
revolutions foc
ODe revolu,ioo of ,he wheel.
Toe truodJe is fix' u on a (lroog iroo axis ealled ' l1e
fpindle, the lower e
of which
tufOS
in a
bra~oot,
¡¡xt at
F,
io ,he horizoo,al beam ST ealled ,he bridge.
tree ; aod ,he upper pa" of ,he fpindle ,uro, in a wooden
bulh
6x,
io,o ,he oether mill(lone whieh lie, "POO beams
io ,he Boor
YY.
The ,op pa" of ,he fpindle above ,he
bulh is fquare, aod goes io,o a
fquar~
hale io a Oroog
iroo crofs
a~cd
(fee fig.
3.)
called ,he ryod; uoder whieh,
and c10fe 'o Ihe bulh, is
a
round piece of thiek lea,her
"pon the fpindte, which il turos round
a\.~he
fame time
as i, does ,he rynd.
The ryod is let io'o grooves io ,he uoder fur(aee of
,he rooning millOooe
G
(6g.
2.)
aod fa turos i, rouod in
the fame timé ,ha, ,he trundle
E
is ,urned round by .he
cog·wheel
D .
T his mill(lone ha.
a
large hale qui.e
through its middle, ealled .he eye of ,he Oone, 'hrough
whieh the micidle pa" of ,he rynd aod upper end of ,he
(piodie
may
be feeo; whil(l ,he four eodo of ,he ryod lie
bid below ,he Oooe io ,heir grooves_
The end T of the bridge·tree TS (whieh fupports ,he
upper milHtone
G
upon ,he fpiodle) is úxed in'o a hale
io the wall; aod ,he eod S is le, io'o a heam
QR
ealled
(he
brayer, whofe cnd
R
remains fixt in
a
mortrre; and
ÜS
o,hor cnd Q..haogs by a (lrong iron rod
P
whieh goes
\hrough ,he /loor
YY,
and has a ferew·nu, 00 its top at
O; by ,he turning of whieh ou', ,he eod
Q..
o( ,he brayer
;, raifed or deprelfed a' pleafure, and eonleq.ently ,he
bridge:tree TS aod upper mill(lone. By ,his
me.ns,,he
upper mill(lone may be fe! as c10fe 'o ,he uoder ooe, or
raifed as high (rom it, as lhe miller pleafes .
T he
"earer the miJIflones are to one another, the finer they
"rind the coro; . and the more remote from one another,
!he coarrer.
The upper millOone
G
is inclofed in a round box
H,
which does not touch it any where ; and is abau t an ¡Deh
cii(l,n, (rom its edge all around.
00
,he top of ,his bOl<
!laods a (raOle for holding ,he hopper
H,
' o
\1
hieh is hllog
Ihe fhoe
1 by
'wo lines (a(lened 'o ,he hiod·pan of i"
6xed upoo hooks io ,he hopper, and by one cnd o( ,he
i:ropk.Oring
K
fa(teoed
10
\he fore.part; of i, al
i;
,he o.
A
N
1
e
s,
,her cnd beiog ,wincd round
,~c
pin
L.
As ' he pin i.
turned one
Wíf.y.
lhe Cl ring draws up lhe fhoe clofer to
lhe hopper, and fo lelfens lhe aperture between lhem;
and as
[he
pin is turned lhe olher way,
it
lets down the
/hoe. and tnlarges the aperture.
I f ,he filOe be drawo up quite ' o ,he hopper, no coro
eao fall from ,he hopper ioto ,he mili; if i, be let a li,de
do\vn, fome will
(all:
and the quantity will
be
more or
lers, aeeording as the fhoe is more or lefs let down. For
lhe hopper is open at bonom, and there is a hole in the
boltom of the Ihoe, oo, diretlly under ,he bottom of ,he
hopper, but forwarder towards the cnd
i
J
Dver
the mid–
dIe of ,he eye of the mill(lone.
There is a fquare hale io ,he top of the fpindle, in
whieh is pu, ,he feeder, (fig.
10.)
Thi, feeder (as ,he
fpindle turns round) jogs lhe Choe [hree
times
in eaeh
re ..
volution, and fo cauCes the corn to
rUD
conflantly down
frcm
the hopper. through ,lhe íboe, ¡mo rhe
eye of the
mill(lone, where [, fa lls upon the ,op of ,he rynd, .od is,
by
the
motion of the
ryod and
the Je:uher undcr
it,
thrown
belo\V ,he upper
(lo"e,
and ground be,weeo il and ,he
lower ane. The violent mation of the llone creates a
centrifugal force
iD
the corn going round with it, by
whieh meaas it gets
farther
and fanher (rom tbe
centre.
as in a
(piral, in every revoJution, untíl it be thrown quite
ou, ; and, beiog then grouod,
it
falls through a fpou,
M,
ealled ,he mill -eye, iota ,he trough
N .
When , he mili is fed '00 fa(l , ,he coro bea" up ,he
Clone. and
i,
ground too coarre
j
and befides, it clogs the
mili fa as 'o make i, go '00 OO\V.
Wheo
,n.,
mili is '00
{lowly fed, it goes '00 fa(l, aod ,he llooes by ,heir a'.
trition are apl to Clrike
6re
againfi one another. Both
which inconvenicocies are a'loided
by
turoing the pin
L backwarcls or forwards, which draws up or let$ down
the filOe; aod fa « gula'es ,he feedio& a. ,he miller fees
convenient.
The ryeavier lhe runniog millllone
¡s,
and the greater
,he quao,i'y?f w.ter ,ha, falls upoo ,he wheel, fa much
,he (a(ler will ,he mili bear ' o be fed ; and eoofequeotly
fa mueh the more i, will griod. A od 00 \he eon!rary,
,he ligh,.r ,he (looe, aod ,he lefs ,he quao,ity of water,
fa mueh Oower mu(l the feediog be.
BU!
wheo ,he Oooe
is eooGderably \Vare, aod beeome light, ,he mili mu(l be
fed /lowly'at any rate; o,herwife ,he Oooe will be
'00
mueh borne up by ,he coro uoder il, whíeh will make me
meal ccarre.
The quao,i,y of power required to 'uro a he,,'y millo
llone
is
but
a very
linte more than what is fufFicient
lo
,¡¡ro
a ligh' poe: for as i, is fuppo"ed opoo ,he fpiodle
by ,he bridge.tree ST, ahd ,he eod of ,he fpindle ,hat
'uros io ,he brafs foot thereio being bu' fmall, ,he odd.
ar¡flag from lhe weight
j,
bUl very inconfiderable in its
aflion againll {he power or force of the water. And be–
fi des, a heavy (lone ha. ,he fame .dvantage
as
a heavy
fly;
nalllely, that
lt
regulates the motion mucb bt.uer {han
a ligh, ooe.
lo arder t" eu' . od griod the coro, bo,h the upper and
undcr milJnones have channels or furrows
CUI
into them,
procecding olJliquely from lhe centre towotrds the circun} ..
fcreoee. Aod ,hefe furrows are eaeh cu, perpcodieularly
on ooe Iide
and
obliquciy 00 ,he olher io,o 'b.e Oone,
.
whieh