IMPROVEMENTS IN THE MANUFACTURE OF GLASS, CHINA, PORCELAIN, EARTHENWARE, AND ARTIFICIAL STONE
Year: 1851

page_text: COME,
ILLIAM
HODGE, of St. Austell, Cornwall, Printer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Second day of October,
One thousand eight hundred and fifty-one, in the fifteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Hodge, my exors, admors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said William Hodge, my
exors, adñors, and assigns, or such others as I, the said William Hodge, my
exors, adiñors, and assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, within England, Wales, and the
Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF GLASS, CHINA, PORCELAIN, EARTHENWARE, AND ARTIFICIAL STONE;"
in which said Letters Patent is contained a proviso, that I, the said William
Hodge, shall cause a particular description of the nature of my said Invention,
and in what manner the same is to be performed, by an instrument in writing
under my hand and seal, to be inrolled in Her Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being.
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Hodge, do hereby declare that the nature of my Invention, and the

page_text: manner in which the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, that is to say:-
My Invention consists of employing hornstone porphyry, also called elvan
or freestone, in the manufacture of glass, china, porcelain, earthenware, and
artificial stone. And in order that my Invention may be most fully understood
and readily carried into effect, I will proceed to describe the means pur-
sued by me in carrying out my Invention. I would, however, state that this
natural production has never before been employed in the manufactures above
mentioned, and may be used in larger or less quantities, according to the class
of manufacture it is desired to produce. In using elvan in the manufacture of
glass, the elvan is to be reduced into a fine powder, which is to be employed in
combination with the materials ordinarily employed, and owing to its being a
natural combination of silex with potash and alum, it will be found highly
useful in the manufacture of glass. I would here state that different speci-
mens of elvan are found to be somewhat different, some containing more and
others less of silex, potash, and alum. The proportions used in the manufacture
of glass will require to be various; thus I have found when the elvan is largely
composed of silex, then it requires a larger quantity of fluor spar to flux it into
glass; and when it contains more potash and alum then a less quantity of fluor
spar will be required for fluxing it into glass; and these observations apply
when using potash, lime, lead, and other fluxes, according to the qualities or
descriptions of glass intended to be made, all which will readily be understood
by manufacturers, and they will adjust the quantities of the silex and the fluxes,
according to the proportions of the matters contained in the particular elvan
employed. In using elvan in the manufacture of glass I have not found that
it requires to be washed; some specimens may however require such process,
nd for very fine qualities of glass washing may be found desirable. In the
manufacture of china, porcelain, earthenware, and artificial stone, this material
(elvan) is used alone, or combined with other materials ordinary employed in
these manufactures, and the elvan is, when for use in the finer classes of these
manufactures, to be ground and washed so as to get it into the best condition
for use,
and in like manner to what other matters used in these manufactures
have heretofore been subjected. The effect of using this material is, that from
its peculiar character it improves the articles produced. In using elvan in the
manufacture of earthenware. it is to be taken in the state of powder and made
into a plastic state by the addition of water; and articles may be made wholly
of the elvan, which will be found to have all the plasticity of clay ordinarily
usel, and may be treated and used in like manner thereto, and when finished
the articles will be found to be much harder and closer in texture than earthen-

page_text: ware in general, and such articles will offer a better appearance, and when
mixed with china clay it will be found to improve the same, the employment of
elvan giving a more stone-like appearance to articles made from such mixtures.
I have not found any limits within which these may be mixed; on the contrary,
I find that a large or a small proportion of elvan may be employed, and the
effect in the ware produced will be in relation to the relative proportions, and
therefore the workman will use his judgment in the quantity he employs,
according to the effect he desires to obtain. Elvan is also applicable in the
manufacture of china and porcelain as a substitute for China stone, China clay,
and fellspar, both in the manufacture of the bodies and glazes, elvan will be
more plastic than china stone when prepared, enabling the manufacturer to use
it in place of china and other clays, and its stone-like character renders it
superior in the manufacture of porcelain and china where such quality is
desired, and the elvan is to be employed with Chinastone or clay, and fellspar
in larger or less quantities, according as it is desired to give to the clays and
fellspar more or less of this peculiar character. I would remark, that although
I have above only spoken of using elvan with other matters in a plastic state,
such material and combination are also capable of being used in a dry state, in
like manner to what is now practised when using clays in making china
articles by dies and pressure, by what is known as the dry process of manu-
facture. When used for glazes the elvan is to be employed in like manner
to that resorted to when using Chinastone and fellspar.
In making artificial stone by employing elvan it will generally require little or
no preparation where found sufficiently fine in its crude state; it is when in a
plastic state to be moulded into articles of the desired shapes, and being dried
these articles are to be baked in a kiln or furnace, in like manner to earthen-
ware; and in making such artificial stone the elvan may be combined with
flint, granite, sand, quartz, or other kind of stone, broken down when necessary
to a state of powder or to a granular condition.
Having thus described the nature of my Invention, and the best means I
am acquainted with for performing the same, I would have it understood that
I do not confine myself to the details or manner of using this material. But
what I claim is the application of hornstone porphyry, also called elvan or free-
stone, in the manufacture of glass, china, porcelain, earthenware, and artificial
stone.
In witness whereof, I, the said William Hodge, have hereunto set my
band and seal this Thirtieth day of March, in the year of our Lord One
thousand eight hundred and fifty-two.
WILLIAM (L.S.) HODGE.

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of March, in the
year of our Lord 1852, the aforesaid William Hodge came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the First day of April, in the year of our Lord One thousand
eight hundred and fifty-two.