The Sun.
London, England, 1822-02-11 00:00:00

THE SOCIETY OF ARTS, ADELPIif,

LONDON:

The 39th volume of the TRANSACTIONS of this
admirable INSTITUTION:*e have just received.
Froth amongst. the several interesting subjects
presented by it to public attention,• we are in-
duced to select the article, on the discovery of a
-QUARRY, OF MILL-STONE In lIALKIN MOUNTAIN,
near Holywell, in Flint Shire.
" Hitherto no millstones for grinding wheat at all compar-
able to the French Buhr had been discovered in Great Britain ;
:and in time of war serious inconvenience had been felt from the
scanty and uncertain supply nf so essential an article. Mr.
Bishop and his partners have had the good fortune to discover,
_and the perseverance to tiring into lair trial, a stone which,
judging from the speciiner-S bud before the Society, and from
very satisfactory testimonials from all the millers who have
'made use of it, bids fair, in a great degree, it' not entirely, to
supersede the necessity of having recourse to a foreign and too
-.-often hostile country for the means or orepaiing our daily
bread."

The import Aime :of this .discovery induces us
to give immediate insertion in our Journal; to
the interesting Paper on ..the subject which has
been published by the Society, as we are desirous
to draw the attention of the public to a circum-
stance which must materially contribute to the
profitable employment of a useful class of la-.
bourers, with great advantage to the farmer and
miller, and to the community at large. It is at
all times a gratifying part of our public duty, but
particularly at the present moment, to give all
the facilities, and all the direction. and encou-
ragement in our power, to the development of
the internal resources of the country, and to the
extensive employment of its native products and
induitry.

FLIN'TSH IR I; MILL-STONES.
Vie smaller, or Isis GOLD MEDAL, was this Session voted to
Mr. W. Sisitor and Co., of Pant y Moch, near Holywell,
Flintshire, for their discovery and Introductioll to actual Use
of a 3111.1.-sTora: of superior quality, found in Halkin

qualities which fits stone for grinding corn, especially
wheat, are hardness, to prevent it as much as possible from wear-
ing down by the constant friction to which it is exposed, a certain
degree of tenacity, to prevent the grinding surface from scaling
or chipping off, and a cellular structure, in bider to increase the
quantity of cutting surface, the walla of the cells being at the
same time thick enough to resist'th'e stranrupon them. •
' The advantages hence 'resulting are,- that the flour is in no
material degree contaminated by the mixture of' earthy particles
abraded from the stones, the grinding is expeditintisly per-
formed, the bra's is completely disengaged from the flour, and
• the dour itself is sexy little heated by passing through, the mill.
This latter circumstance is of great importance, it being found,
by experience, that flour over-heated,..-xiir.Ei), as the tech-
nical phrase is, will never produce brad so light as that which
is grOund cool. -
In some parts of the valley of the Seine, and of the adjoining
districts in which the fresh-water" limestone occurs, is found it
siliceousrock, in detached masses or blocks; of various size,
known on the spot. and in commerce by the name of Bulia.
it is a. substance intermediate between lurrnstoae and chalce-
dony, and possessef, in an eminent degree, the qualities which
peculiarly fit it for grinding wheat; $ll the fine flour required
for the supply of the metropolis-and of the other large towns in
this island is prepared by meant of mill-stones of French bull!,
cireinnstance which, beside rendering us dependant.' on fia-'
reigners for so' essential an article, is the occasion in time of war
Of enormously.enhancing the price, and subjecting our millers
to great inconvenience. . ' • • • •.
The northern shore of the Isle of Wight is the only district
in this „country in which the fresh-water limestone has hitherto
been found, but it does not appear to contain any buhr-stone.
The entrochital .ebert or horn-stone (vulgarly called sciii-Av-
STONE) which occurs interstiatified with the mountain lime-
stone in Derbyshire, as it resembles bulir-stone in quality and
totture, has occasionally been made trial-of for a •griliding-
stbne, but always unsuccessfully on account of its fragility and
Softhess;—SEC. , •
__ •

.In the year 1816,. Mr. Thomas llooson, of Flint, observed
On llalkin Mountain a bed of remarkably fine porcelain clay,
,Which, on exposure to the potters' fires, was found to assume a
More delicate whiteness than any substance of a sitnilar nature
,hitherto found in this kingdom ; and seeing also other lub-
stance's which he thought likely to be Useful to the potters; he
obtained from Earl Grosvenor a lease of all clays; rocks, arid
stones (except lime-stone). withinlds Lordship'S liberties ;• and
aubiequently, with. a view to an extended trade, formed his
.present partnership with. Richard Fyriney; 'Mr. William
Bishop, and Mr. 3ames Whitehead, established under the-iiim
-of the " Welsh Company at Nam y Bloch, bear Holy Well,"
where they have.erected works for preparing the clay, which is
called '° Cambria," for sale, by separating it from'a sili-
ceous sand and rock; with which the bed is found mixed tp a
depth at present unknown, 'but which has been proved as deep
as 26 yards. The sand, when separated, is used for glass-
making ; and the white siliceous rock, now called Hock
.Cainbna," is ground
.doWn and used in the composition of
china and earthenware, instead of ground flint, or is mixed with
it. For this process of grinding, several thousand tons of chert
are annually consumed in the. Staffordshire potteries, and much
is supplied from Halkin Mountain. In quarrying this chert,
some of it in the state
,of vesicular entrochita horn-stone was
raised; which,. when Used together with common chest, incli-
c*ed such a superiority by its expedititzus grinding and its little
wear, and showed such a proximity in appearance (after having
been worked) to the French buhr that its use for grinding wheat
was considered probable; and this led to the first application of
the vesicular lialkin rock as a buhr-stone. •

• Halkin Mountain .(called " Alchene" at the Conquest, ac-
cording to. Pennant) is a range of high uncultivated land, in
Flintshire; the mineral property of the Right Honourable'Earl
GrasVenor. On the island side it runs parallel to the boundary
hills of the vale of Clwyd ,• and`nri the north-east stretches from
HblyWell for about four miles till nearly opposite Northop, in an
angle of about twelve degrees with thu river 'Dee; and average's
atfupt, a mile in breadth. It is composed of mountain lime-
stone,--with the usually accompanying rocks, and abounds with
la* veins containing 'lead ore, blemie, and calamine, with
some appearances of copper ; it also'affords a rock of a whitish
quartz; well adapted for certain kinds of Mill-stones, for which
(according to all our old histnrians) Flintshire has been fanious.
B.nt•these quarries had been neglected for niany' years, till lately
reopened by the discoverers of the still more valuable buhrs,
and promise to regain their celebrity as.grey-stones for' grinding'
oats .Zic

'buhr-stone itself; -or :entrochital horn-stone, is found
near the middle of the eastern ridge of Halkin mountain, and
On the West side of the ridge; into which it penetrates with a dip
of about' one yard in six. Its present appearance presents a
betl.of about four yards thick, between two layers of a compact
siliceous-slaty Chat, covered with a shivery siliceous shale. D.
eastwardly, like all the other' strata on' the moUntain,
whiCh consist of lirne-Stobe rock and chat. The buhr-stratum
is principally of the same quality •hs the small mill-stone sent
:herewith, and attested bY Dr. Train (eertificate,-No. 1):; but
mitten -masses sometimes occur, and blocks are occasionally.
found of too close a texture for the Miller ; and 'sane few are
quite solid. Still the corrailite structure pervades the 'Whole :
the .t ntrochites being, perfect and entire in some instances,'
while in the chief parts of the 'bed the casts :Hone rernhin ;
-finis, leaving' the rock' Vesicular, and this respect differing
from the nature of the- pores in the French bohr,
pear to-haire been eiiiisett by corrosion, their-edges being rusty
and impure, whereas those in the Halkiii itim: are of pure
'flint, and exceedingly sharp and hard. '" •
The ,quarry froM which all the buhrs hitherto used have
been procured, now presents a fore-breast of forty' yards, 'and
is of, the same quality and, thickness' ha at first, but has a
thicker covering of shale, as it dips into the till. 'At the
distapce of a mile* the north-west; a second quarrry is now
'opening, and appears similar in every respect to the former
and-filinfragmenti of huhr here and•there found; with pieces
of, shale .and--. of chest, half concealed in the thountain turf,
traces ,or the, same stratum ,May be observed froth the one
quarry, to- the other.' About halfa mile-to the SOuth-east of
he. main 41,tarry, in the saUie dhert-famation, .the *bull e-itone:
'llSO;aeirriii ; and lb the 1,411ty-. at till fohi'tif the