IMPROVEMENT IN COATING OR COVERING IRON AND COPPER FOR THE PRE- VENTION OF OXIDATION
Year: 1837

page_text: CRAUFURD'S SPECIFICATION, DISCLAIMER AND
MEMORANDUM OF ALTERATION, AND DISCLAIMER.
SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
WILLIAM CRAUFURD, of John Street, Berkeley Square, in the County of
Middlesex, Commander in the Navy, send greeting.
WHEREAS His late most Excellent Majesty King William the Fourth
by His Royal Letters Patent under the Great Seal of Great Britain, bearing
date át Westminster, the Twenty-ninth day of April, in the seventh year of
His reign, and in the year of our Lord One thousand eight hundred and
thirty-seven, did, for Himself, His heirs and successors, give and grant unto
me, the said Henry William Craufurd, His especial license, full power, sole.
privilege and authority, that 1, the said Henry William Crauford, my exe-
cutors, administrators, and assigns, and such others as I, the said Henry
William Crawford, my executors, adñiors, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term-of
years therein mentioned; should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and
also in all His Majesty's Colónies and Plantations abroad, an Invention.of
an "IMPROVEMENT IN COATING OR COVERING IRON AND COPPER FOR THE PRE-
VENTION OF OXIDATION;" being a communication from a Foreigner residing

page_text: abroad; in which said Letters Patent is contained a proviso obliging me,
the said Henry William Craufurd, by an instrument in writing under my
hand and seal, particularly to describe and ascertain the nature of the said
Invention, and in what manner the same is to be performed, and to cause the
same to be inrolled in His 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
Henry William Craufurd, do hereby declare that the nature of the said
Invention, and the manner in which the same is to be performed, is parti-
cularly described and ascertained in and by the following description thereof
(that is to say)
The coating which preserves iron and copper from oxydation is a coating
of zinc, which in some cases may be covered with a second coating of pure
tin, or of tin alloyed with lead. The zinc may be used either in a state of
fusion or in a solid state reduced into powder, and applied as a paint, which
then takes the name of galvanic paint.

page_text: oxidation taking place, but not so when the preparation of the metal is
effected as follows, (that is to say,) by dipping the pieces of metal separately,
when they are not too small, in a solution of sal ammoniac, or what is prefer-
able, in water acidulated with muriatic acid. This bath is made of nearly
equal quantities of acid and of water. The metal pieces when taken out of
this bath must be dried immediately,and coated with as little delay as possible,
for within two hours after being immersed in the muriatic acid the iron
would rust. The pieces of metal may be dried by holding them over a
reverberating furnace, of which we shall speak hereafter.
Zinc coating given to sheet iron or copper, or largest pieces of such metals._
The first coating is given with zinc, which must be melted in a crucible of
earthenware, or if it be made of cast iron the crucible must be lined internally
with bricks or with an earthen lining of some kind in order to prevent any
contact between the cast iron and the melted zinc, otherwise an alloy of zinc and
cast iron would thus be produced, which would prevent the zinc from adhering
to the metal operated upon. Cast-iron vessels of a shape similar to those
employed for the tinning of sheet irou may be used for this operation, provided
they be internally lined with fire bricks well joined together with potter's clay.
The zinc being melted it must be skimmed carefully, and its surface covered
with sal ammoniac or any flux. The pieces of copper or iron, previously pre-
pared as stated, are introduced into the melted metal; they must be moved about
in the melted zinc and drawn out slowly to avoid taking up too much zinc, and
if possible before the zinc adhering to the surface of the iron or copper has
become set, these pieces must be thrown into clean water and rubbed therein
with a sponge or a brush. They are then dried rapidly by passing them
through bran or sawdust. It is necessary to wash and dry the pieces of metal
immediately after they have received the zinc coating, without this precaution
the zinc coating would be defaced by black spots. When prepared as stated,
they are white, and might be made still more so if rapidly dipped in water
acidulated with sulphuric acid previously to being thrown into the clean water.
The melted zinc must not be too warm; the operation of coating with zinc
must begin shortly after the zinc has become fused. If the zinc were too hot
it would rapidly volatilize the sal ammoniac, which must at all times cover its
surface; when plates of small dimensions and of the ordinary size of tin plates
are to be coated, several may be done at once.
vertically in a grated case held by two handles.
apart by means of a separation formed by iron
They are to be placed
The plates should be kept
wires fixed to the grating.
In this operation, to save as much fuel and sal ammoniac as possible, two

page_text: workmen must be employed for each vessel. These workmen placed opposite
to one another are to be provided with a grated case each; large pieces of
metal must be singly introduced into the fused metal by means of tongs or
forceps, the jaws of which must form an acute angle in order to leave smaller
marks,on the metal. The large pieces of metal must be introduced very
slowly in the melted zinc, for without that precaution an explosion might take
place, and the melted zinc be projected out of the vessel. When the plates of
metal warp in consequence of the heat of the zinc into which they are
dipped, or if their surface is uneven, they must be rolled; and to avoid their
departing still more from their original form when passing through the rollers,
these metallic plates must be powdered with wood ashes, rosin, or any other
pulverized substance, which will prevent the rollers sliding over any portions
of the plates. When large chains are to be coated they are to be prepared in
the manner described for the other large pieces, only when they are taken out
of the melted zinc they are to be shaken, in order to hinder the links from
becoming soldered to one another.
Preparation and coating of small pieces of metal, such as nails, sinal!
chains, &c. These small pieces of metal are dipped into the acidulated bath
as described, and must be moved about so that the acid may act equally on
every part, and that by the friction of these picces or links against one
another the oxide may be removed. They are then dipped into muriatic acid
and dried in a reverberatory furnace, and the coating of zinc is given in the
following manner :-These pieces are thrown altogether in the melted zinc
covered with sal ammoniac, and there left for perhaps the space of one minute.
They are taken out slowly with an iron skimmer, and by small portions at a
time, in order to allow them to drop as much as possible of the zinc they have
taken up. All these pieces so removed are necessarily held in contact or
soldered together. As they still retain a great deal too much zinc, to free
them therefore from this excess of zinc and detach them, they are to be put
altogether in a reverberatory furnace and covered with charcoal. A red heat
is to be maintained during about a quarter of an hour, and the mass is moved
and shaken by means of a large iron poker until the pieces of metal have
discharged the excess of zinc they had taken up. They are then drawn to
the front of the furnace by means of an iron rake, and the whole must
be shaken about until the zinc becomes set. The remainder of the process is
the same as for large pieces of metal. The zinc for coating small pieces of
metal, and especially nails, must be melted in a small crucible. to avoid the
possibility of spoiling a great quantity of zinc, for if any iron be left for

page_text: a certain time in the melted zinc the latter can no longer be used for coating
metal. The zinc used for the purpose of coating must be very pure. To
prepare wire it must be made to pass horizontally through the melted zinc
covered with sal. ammoniac. The wire prepared in the manner described is
placed on a drum and introduced into the vessel and made to pass through
the zinc, and maintained in a proper direction by any suitable contrivance.
When it emerges from the zinc it is to be roller on another drum, and must
be afterwards cleaned, as described above.
Galvanic paint. The galvanic paint having the property of preserving iron
and copper from oxydation is composed of zinc powder well ground and mixed
with the substances generally employed for painting. All substances are not
equally suitable for preparing the galvanic paint. The oils distilled from coal
tar answer very well for this purpose. Coal tar itself, to which must be
added one third of the quantity of spirit of turpentine, will produce a very
good result, but owing to its very disagreeable odour it cannot be used for all
purposes.
Second coating with tin.--The second coating is more particularly applied
to sheets or large pieces of metal the necessity of applying it will but
rarely occur, and only in cases where the zinc coating might be corroded
by the contact of certain substances, or when the vessels intended to be
made of metal coated with zinc are to receive acids or be used in the prepara-
tion of food; pure tin or in some cases tin mixed with two thirds of lead may
be used for this object. These metals are melted in a cast-iron crucible.
The pieces which are to be tinned must be rubbed with a sponge or a
brush moistened with a solution of sal ammoniac, or with a solution of
muriatic acid, and the pieces of metal thus moistened are dipped in the melted
tin or tin and lead, which must be covered with a layer of fat or tallow at least
two inches thick; the fused metal must be very hot, and nearly hot enough
tinflame the fat. The pieces must be dipped rapidly in the fused metal one
by one, but must be drawn out slowly, that the tin may cover the whole of the
zinc. The pieces operated upon must not be drawn out too slowly, for in
that case the zinc might quit them, and thus not only the whole of the fused
metal would be spoiled, but moreover a portion of the zinc coating being
removed the metal would be exposed to oxydation.
In witness whereof, I, the said Henry William Craufurd, have here-
unto set my hand and seal, this Nineteenth day of October, in the
year of our Lord One thousand eight hundred and thirty-seven.
(L.S.) HENRY WILLIAM CRAUFURD.

page_text: AND BE IT REMEMBERED, that on the Nineteenth day of October, in
the first year of the reign of Her Majesty Queen Victoria, the said Henry
William Craufurd came before our said Lady the Queen in Her Chancery,
and acknowledged the Instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the Instrument
aforesaid was stamped according to the tenor of the Statute made in the
fifty-fifth year of the reign of His late Majesty King George the Third.
Inrolled the Nineteenth day of October, One thousand eight hundred and
thirty-seven,

page_text: En the Matter of a Patent granted to Henry William Craufurd, of John
Street, Berkeley Square, in the County of Middlesex, Commander
in the Navy, for the Invention of "AN IMPROVEMENT IN COATING OR
COVERING IRON AND COPPER FOR THE PREVENTION OF OXIDATION," bearing
date at Westminster, the Twenty-ninth day of April, One thousand
eight hundred and thirty-seven, a Specification to which Letters
Patent has been duly inrolled, and which said Letters Patent have
been assigned to Louis Count Jelski, of Paris, in the Kingdom of
France, and by him, the said Louis Count Jelski, assigned to (and
all interest therein is now vested in) John James Siordet, John
Charles Louis Meyer, and Robert Louis Siordet, of No. 3, Saint
Helen's Place, Bishopsgate, in the City of London, Merchants.
DISCLAIMER AND MEMORANDUM OF ALTERATION proposed to
be entered by the said John James Siordet, John Charles Louis Meyer,
and Robert Louis Siordet with the Clerk of the Patents of England,
pursuant to an Act passed in the fifth and sixth year of His late
Majesty's reign, intituled "An Act to amend the Law touching Letter
Patent for Inventions."
WHEREAS the said Henry William Crawfurd, in the Specification inrolled
by him to the said Letters Patent, did describe the Invention to consist in
coating iron and copper with zinc, first, by means of immersing the iron and
copper
in zinc kept in a state of fusion; and, secondly, by employing what he
called galvanic paint. And it is further stated that the iron and copper so
coated with zinc might have a coating of tin, or tin alloyed with lead. Since
he inrolled the said Specification, we, the said John James Siordet; John
Charles Louis Meyer, and Robert Louis Siordet, have been advised that the
title in the said Letters Patent being for "An Improvement," &c. two distinct
methods of coating iron and copper with zinc could not legally be inserted in
the Specification, we do therefore wish to disclaim and do hereby disclaim all
that part of the Specification and description of the Invention contained
therein which relates to coating iron or copper with what is therein called
galvanic, paint; and also all that part of the Specification which relates to

page_text: applying a second coating of tin, or tin alloyed with zinc, intending by such
Disclaimer to restrict the Invention secured by the said Letters Patent to the
mode of coating copper and iron for the prevention of oxydation by immersing
the same in melted zinc. And we have been further advised, in respect to the
description of the said mode of coating iron and copper with zinc by immer-
sion, that the using of the words "or any flux" in the sentence "The zinc
being melted it must be skimmed carefully, and its surface covered with sal
ammoniac or any flux," &c. is not a correct expression, and that the words
"or any flux" had better have been omitted. We do therefore wish to
explain and we do hereby explain the sense in which such words were
intended to apply was as follows:-Sal ammoniac being placed on the surface
of the melted zinc prevents the atmospheric air coming in contact therewith,
and further the passing articles of iron or copper through such floating sal
ammoniac facilitates the process of coating the iron or copper with zinc, and
the words "any flux" were inserted with a view to state that any matter acting
in a like manner might be used.
In witness whereof, I, on behalf of the said John James Siordet, Jolin
Charles Louis Meyer, and Robert Louis Siordet, have hereunto set
my hand, this Fourteenth day of March, One thousand eight hundred
J. J. SIORDET, in behalf of self, JOHN CHARLES
LOUIS MEYER, & ROBERT LOUIS SIORDET.
To the Clerk of the Patents of England.
This is to certify that the above-named John James Siordet, John Charles
Louis Meyer, and Robert Louis Siordet, of N° 3, Saint Helen's Place,
Bishopgate, in the City of London, Merchants, Assignees of the said Patent,
have applied to me for leave to enter with you the above-written Disclaimer
and Memorandum of Alteration of part of the Specification of a certain
Invention, for which Letters Patent were duly granted to Henry William
Craufurd, of John Street, Berkeley Square, in the County of Middlesex,
Commander in the Navy, under the Great Seal, dated at Westminster, the
Twenty-ninth day of April, One thousand eight hundred and thirty-seven, and
in considering of the said application I directed them to advertize their said
Disclaimer and Alteration in the London Gazette and in the Times and
Morning Chronicle Newspapers, and such advertisements have been duly
-made in the said Gazette on the Eleventh day of January, and in the Times
and Morning Chronicle on the Twelfth day of the same month of January,

page_text: One thousand eight hundred and thirty-nine, I have accordingly granted leave
to the said John James Siordet, John Charles Louis Meyer, and Robert
Louis Siordet to file their said Disclaimer and Memorandum of Alteration.
pursuant to the Statute passed in the sixth year of the reign of His late
Majesty, intituled "An Act to amend the Law touching Letters Patent for
31
AND BE IT REMEMBERED, that on the Fourteenth day of March,in' the
second year of the reign of Her Majesty Queen Victoria, the said John James
Siordet came before our said Lady the Queen in Her Chancery, and acknow-
ledged the Instrument aforesaid, and all and every thing therein contained
and specified, in form above written. And also the Instrument aforesaid was
stamped according to the tenor of the Statute made in the fifty-fifth year of
the reign of his late Majesty King George the Third.
Inrolled the Fourteenth day of June, One thousand eight hundred and

page_text: In the Matter of a Patent granted to Henry William Crawfurd, of John
Street, Berkley Square, in the County of Middlesex, Commander in
the Royal Navy, for his Invention of "AN IMPROVEMENT IN COATING
OR COVERING IRON AND COPPER, FOR THE PREVENTION OF OXYDATION."
WHEREAS by Letters Patent under the Great Seal of the United King
dom of Great Britain and Ireland, bearing date at Westminster, the Twenty-
fifth day of April, in the seventh year of the reign of His late Majesty King
William the Fourth, His said late Majesty did grant unto Henry William
Crawfurd, of John Street, Berkley Square, in the County of Middlesex,
Commander in the Navy, his executors, administrators, and assigns, the sole
use, benefit, and advantage of his Invention, therein intituled "An Improve-
ment in Coating or Covering Iron and Copper, for the Prevention of Oxyda-
tion," to have, hold, exercise, and enjoy the same unto the said Henry
William Craufurd, his executors, administrators, and assigns, within England,
Wales, and the Town of Berwick-upon-Tweed, and also in all His Majesty's
Colonies and Plantations abroad, for the term of fourteen years thence next
ensuing: And whereas, the said Henry William Craufurd, in pursuance of a
proviso in the said Letters Patent contained, did, by an instrument in writing
under his hand and seal called a Specification, describe and ascertain the
nature of the said Invention, and in what manner the same was and is to be
performed, and did cause the said Specification to be inrolled in the High
Court of Chancery at Westminster on the Nineteenth day of October, One
thousand eight hundred and thirty-seven: And whereas, by virtue of divers
mesne assignments and other acts in the law, the rights, privileges, profits,
benefits, and advantages granted by the said Letters Patent, together with the
same Letters Patent, became and are now vested in us, John James Siordit, John
Charles Louis Meyer, and Robert Louis Siordet: And whereas the said Henry
William Craufurd in the said Specification did describe the said Invention to
consist in coating iron and copper with zinc, first, by immersing the iron and
copperin zinc kept in a state offusion, its surface being covered with sal ammo-
niac; and, secondly, by employing what he called galvanic paint; and it is further
stated, that the iron and copper so coated with zinc might have a coating of
tin alloyed with lead: And whereas since the said Henry William Craufurd
inrolled the said Specification, we, the said John James Siordet, John
Charles Louis Meyer, and Robert Louis Siordet, have been advised that the
said title in the said Letters Patent being "An Improvement in Coating or
Covering Iron or Copper for the Prevention of Oxydation," it is doubtful
whether two distinct methods of coating iron and copper with zinc could be

page_text: legally inserted in the said Specification, and we have also been advised that
the use of the words "or any flux" is incorrect.
NOW THEREFORE KNOW YE, that we, the said John James Siordet,
John Charles Louis Meyer, and Robert Louis Siordet have obtained leave of
Sir John Jervis, Knight, Her Majesty's Attorney General, certified by his
fiat and signature, to enter with the Clerk of the Patents of England, accord-
ing to the Statute in that case made and provided, a Disclaimer of all that part
of the said Specification and description of the Invention contained therein
which relates to coating iron or copper with what is therein called galvanic
paint, and also all that part of the Specification which relates to a second coating
of tin or tin alloyed with lead, and also the words "or any flux;" and we, for
the aforesaid reason that it is doubtful whether two distinct methods of coating
iron and copper with zinc could be legally inserted in the said Specification,
do hereby disclaim such parts of the said Specification which in any way
describe or relate to coating iron or copper with what is called galvanic paint,
and also which describe or relate to a second coating of tin or tin alloyed with
lead. And in respect to the description of the said mode of coating iron and
copper with zinc by immersion, the use of the words "or any flux" in the
sentence "The zinc being melted, it must be skimmed carefully, and its surface
covered with sal ammoniac or any flux, &c.," is not a correct expression, and
that the words "or any flux," had better have been omitted, and therefore we
do for such reason disclaim the said words "or any flux" in the said Specifi-
cation, intending by such Disclaimer to restrict the Invention secured by tlie
said Letters Patent to the mode of coating copper and iron for the prevention
of oxydation by immersing them in melted in zinc, having its surface covered
with sal ammoniac.
In witness whereof, we, the said John James Siordet, John Charles
Louis Meyer, and Robert Louis Siordet, have hereunto set our hands
and seals, this Tenth day of July, in the year of our Lord One thousand
eight hundred and forty-eight.
JOHN JAMES SIORDET. (L.S.)
JOHN CHARLES LOUIS MEYER. (L.s.)
ROBERT LOUIS SIORDET. (L.S.)
Taken and acknowledged by Robert
Louis Siordet (one of the parties
hereto) at Hamburgh, this Tenth
day of July, 1848, before me,

page_text: To the Clerk of the Patents of England.
This is to certify, that John James Siordet, John Charles Louis Meyer, and
Robert Louis Siordet, have applied to me for leave to file with you the above-
written Disclaimer of a certain Invention for which Letters Patent were
granted to Henry William Craufurd, of John Street, Berkley Square, in the
County of Middlesex; Commander in the Royal Navy, under the Great Seal,
bearing date the 25th day of April, 1837, and to which he did enrol his
Specification on the 19th day of October, 1837, and which said Invention has
been assigned to them, and on considering of the said application I directed
them to advertise the said Disclaimer in the London Gazette, the Times,
the Morning Chronicle, and Aris's Birmingham Gazette Newspapers; and
such advertisements having been duly made, and no objection having been
made to the said application, I have accordingly granted leave to the said
John James Siordet, John Charles Louis Meyer, and Robert Louis Siordet
to file the said Disclaimer pursuant to the Statute passed in 'the 5th & 6th
years of the reign of His late Majesty, entitled An Act to amend the Law
touching Letters Patent for Inventions..
Temple,
31 August, 1848.
Entered with and filed by the Clerk
of the Patents of England, this
2d day of September, 1848.
JOHN JERVIS.
AND BE IT REMEMBERED, that on the Twenty-sixth day of July, in the
twelfth year of the reign of Her Majesty Queen Victoria, the said John James
Siordet and John Charles Louis Meyer came before our said Lady the Queen
in Her Chancery, and acknowledged the Instrument aforesaid, and all and every
thing therein contained and specified, in form above written. And also the
Instrument aforesaid was stamped according to the tenor of the Statute
made in the fifty-fifth year of the reign of His late Majesty King George
the Third.
Jurolled the Second day of September; One thousand eight hundred