MECHANICS. 
region in which the floatboards, C, are placed on the face 
of the wheel. 
In the common water-wheels, more than half the quan¬ 
tity of that fluid pafles from the gate through the wheel, 
without affording it any afliftance : the affion of the floats 
is refitted by the incumbent atmofphere, at the moment 
when thefe leave the furface of the tail-water; and, as a 
fimilar proportion of water with that which pafled between 
the floats at the head neceflarily flows between them at 
the tail, the motion of the wheel is greatly impeded. On 
the contrary, by Mr. Befant’s contrivance, no water can 
pal's, excepting that which afls with all its force on the 
extremity of the wheel; and, as the floats emerge from 
the water in an oblique direction, the weight of the at¬ 
mofphere is thus prevented from taking any effect. Al¬ 
though his new wheel is confiderably heavier than thofe 
conftrufted on the old plan, yet it revolves more eafily on 
its axis ; the water having a tendency to float it. Laftly, 
repeated experiments have proved Mr. Befant’s wheel to 
be fo decidedly fuperibr, that, when working in deep 
tail-water, it will carry weights in the proportion of three 
to one; on which account it will be particularly fervice- 
able to tide-mills. 
Mills with oblique floats are mod ufeful for employing 
fmall ft reams which can be delivered from a fpout with a 
great velocity. M. Boffin has confidered thefe with much 
attention, and has afcertained the beft modes of conftruc- 
tion. There are two which have nearly equal perfor¬ 
mances : i~. The vanes being placed like thofe of a wind¬ 
mill round the rim of a horizontal or vertical wheel, and 
being made much broader than the vein of water which 
is to (trike them perpendicularly. By thefe means it will 
be fpread about on the vane in a thin flieet, and exert a 
preffure nearly equal to twice the weight of a column, 
whofe bafe is the orifice of the fpout, and whofe height is 
the fall producing the velocity. Mills of this.kind are 
much in ufe in the fouth of Europe. The wheel is hori¬ 
zontal, and the vertical axis carries the millftone ; fo that 
the mill is of the utmoff fimplicity, and this is no fmall 
recommendation. Drawings of fuch mills may be feen in 
Bockler, Leupold, and Belidor. 2. The vanes may be 
arranged round the rim of the wheel, not like the fails of 
a windmill, but in planes inclined to the radii, though 
parallel to the axis, or to the planes pafling through the 
axis. They may either (land on a foie, like the oblique 
floats recommended by De Parcieux ; or they may ftand 
on the fide of the rim, not pointing to the axis, but afide 
from it. This difpofition will admit of the fpout being 
more conveniently difpofed either for a horizontal or a 
vertical wheel. 
In the fouthern provinces of France, where horizontal 
wheels are very generally employed, the floatboards are 
made of a curvilineal form, fo as to be concave towards the 
ftream. The chevalier de Borda obferves, that in theory 
a double effefl is produced when the floatboards are con¬ 
cave, but that this effect is diminifhed in praftice from 
the difficulty of making the fluid enter and leave the curve 
in a proper direction. Notwithffanding this difficulty, 
however, and other defects which might be pointed out, 
horizontal wheels with concave floatboards are always 
i'uperior to thofe in which the floatboards are plane, and 
fometimes to vertical wheels, when there is a fufficient 
head of water. If the fall of water be five or fix feet, a 
horizontal wheel with concave floatboards may be erected, 
whofe maximum effect will be to that of ordinary vertfi 
cal wheels as 3 to 2. 
We may now (how the application of thefe wheels to 
the work of a corn-mill; and we (hall inftance the com¬ 
mon breafl-mill, where the fall of water may be about ten 
feet. In Plate XXVIII. fig, 104. A A is the great wheel, 
which is generally about leventeen or eighteen feet dia¬ 
meter, from a, the outerinoft edge of any fioatboard,to b, 
that of its oppofite float. To this wheel the water is con¬ 
veyed through a channel, and, falling upon the wheel, 
turns it round. This wheel is without the mill-trough : 
Vol.XIV, No, ion. 
763 
but on its axis, BB, which pafles through a hole made in 
the wall, and within the mill-houfe, is a wheel D, about 
eight or nine feet diameter, having 61 cogs, which turns 
a trundle E, containing 10 upright (haves or rounds ; and, 
when this is the number of cogs and rounds, the trundle 
will make 6^\,- revolutions for one revolution of the w heel. 
The reafon of adding an odd cog, called the hunting-cog, 
to the wheel, is this : that, as every cog comes to the 
trundle, it may take the next ftaff or round behind the 
one which it took in the former revolution, and thus it 
will wear all the parts of the cogs and rounds which work 
upon one another equally, and to equal dilfances from 
one another, in a little time; and make a true uniform 
motion throughout the whole work. The trundle is fixed 
upon an iron axis called the fpindle, the lower end of 
which turns in a brafs foot, fixed at F, in the horizontal 
beam ST, called the bridge-tree ; and the upper part of 
the fpindle turns in a wooden bufli fixed into the lower 
millftone, which lies upon beams in the floor Y Y. The 
top part of the fpindle above the bufli is fquare, and goes 
into a fquare hole in a ftrong iron crofs, abed, fig. 105. 
called the rynd\ under which, and clofe to the bulh, is a 
round piece of thick leather upon the fpindle, which it 
turns round at the fame time as it does the rynd. The 
rynd is let into grooves in the under furface of the run¬ 
ning millftone G, fig. 104. and fo turns it round in the 
fame time that the trundle E is turned round by the cog¬ 
wheel D. This millftone has a large hole quite through 
its middle, called the eye of the ftone, through which the 
middle part of the rynd and upper end of the fpindle may 
be feen; whilft the four ends of the rynd lie hid below 
the ftone in their grooves. The end T of the bridge-tree 
TS (which fupports the upper millftone G upon the 
fpindle) is fixed into a hole in the wall; and the end S is 
let into a beam Q R called the brayer, whofe end R re¬ 
mains fixed in a mortife, and its other end Q hangs by a 
ftrong iron rod P, which goes through the floor Y Y, and 
has a ferew-nut at its top at O ; by the turning of which 
nut, the end Q of the brayer is raifed or depreffed at plea- 
fure; and, confequently, the bridge-tree TS and upper 
millftone. By this means the upper millftone may be let 
as clofe to the under one, or raifed as high from it, as the 
miller pleafes. The nearer the millftones are to one ano¬ 
ther, the finer they grind the corn ; and the more remote 
from one another, the coarfer. The upper millftone G 
is inclofcd in a round box H, which does not touch it 
any-where ; and is about an inch diftant from its edge all 
around. On the top of this box ftands a frame for hold¬ 
ing the hopper kk, to which is hung the (hoe I, by two 
lines fattened to the hind-part of it,‘ fixed upon hooks in 
the hopper, and by one end of the crook-ftring K faftened 
to the fore-part of it at i ; the other end being twifted 
round the pin L. As the pin is turned one way, the firing 
draws up the fhoe clofer to the hopper, and fo leflens the 
aperture between them ; and, as the pin is turned the other 
way, it lets down the fhoe, and enlarges the aperture. If 
the (hoc be drawn up quite to the hopper, no corn can 
fall from the hopper into the mill; if it be let a little 
down, fome will fall: and the quantity will be more or 
lefs, according as the fhoe is more or lefs let down. For 
the hopper is open at bottom, and there is a hole in the 
bottom of the fhoe, not direftly under the bottom of the 
hopper, but forwarder towards the end i, over the middle 
of the eye of the millftone. There is a fquare hole in the 
top of the fpindle, in which is put the feeder e, fig. 105. 
this feeder (as the fpindle turns round) jogs the (hoe three 
times in each revolution, and fo caules the corn to run 
conftantly down from the hopper, through the (hoe, into 
the eye of the millftone, where it falls upon the top of the 
rynd, and is, by the motion of the rynd and the leather un¬ 
der it, thrown below the upper ftone, and ground between 
it and the lower one. The violent motion of the ftone 
creates a centrifugal force in the corn going round with 
it, by which means it gets farther and farther from the 
centre, as in a fpiral, in every revolution, until it is 
9 I thrown 
