A MEAN OB MEANS, PROCESS OR PROCESSES, FOR IMPROVING THE QUALITY OF COPPER, AND OF ALLOYED COFFER, APPLICABLE TO THE SHEATHING OF SHIPS AND OTHER PURPOSES
Year: 1823

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MUSHET, of the Royal Mint, Tower Hill, in the County of Middlesex, Gentle-
man, send greeting.
WHEREAS His present Majesty King George the Fourth, by His Letters
Patent under the Great Seal of Great Britain, bearing date at Westminster,
the Fourteenth day of June now last past, did give and grant unto me, the
said Robert Mushet, His especial licence, full power, sole privilege and
authority, that I, the said Robert Mushet, my executors, administrators, and
assigns, and such others as I, the said Robert Mushet, my executors, adminis
trators, or assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, and in all His sald Majesty's
Colonies and Plantations abroad, my Invention of "A MEAN OB MEANS, PROCESS
OR PROCESSES, FOR IMPROVING THE QUALITY OF COPPER, AND OF ALLOYED COFFER,
APPLICABLE TO THE SHEATHING OF SHIPS AND OTHER PURPOSES;" in which said
Letters Patent there is contained a proviso obliging me, the said Robert
Mushet, by an instrument in writing under iny hand and seal, particularly
to describe and ascertain the nature of my said Invention, and in what
manner the same is to be performed, and to cause the same to be inrolled in

page_text: His Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said recited Letters Patent, as in and
by the said recited Letters Patent, reference being thereunto had, will more
fully appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Mushet, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained by the following description thereof, that is to say :—
It may be proper to remark, that it has long been a general complaint that
the copper sheathing of ships now in very general use is so quickly acted upon
and destroyed when exposed to sea water as to occasion great expence by the
frequency with which the ships are obliged to be re-coppered; and that the
said sheathing is generally manufactured of what is known by the name of
toughened or refined copper without any alloy. And that my.said Invention
consists, in the first place, in giving to such copper an increased degree of
tenacity, or a more fibrous texture, than it possesses in the state in which it is
usually applied to such manufacture, thereby rendering it actually more strong
and durable and better adapted to resist the corroding action of the sea water;
and that I communicate such increased tenacity or more fibrous texture by
adding to such copper a certain portion or portions of alloy or alloys, by which
it is also rendered better applicable to other purposes in which strength and
durability are desirable; and that, in the second place, my said Invention
consists in bringing copper that has by any accident, or for any purpose, been
previously too much alloyed for copper sheathing to such an improved degree
of tenacity or fibrous texture as to be applicable to such manufacture. And I
effect the same in manner following, that is to say:-I improve the quality of
toughened or refined copper for the purpose of being applied to the sheathing
of ships and other purposes by adding thereto in the common reverberatory
furnace a certain portion or portions of alloy or of alloys, as herein-after
mentioned, namely, regulus of zinc, commonly called speltre, in the proportion
of two ounces avoirdupoise to one hundred pounds avoirdupoise of the said
copper, or by adding to one hundred pounds thereof two ounces of grain or
block tin, or four ounces of regulus of antimony, or eight ounces of regulus of
arsenic. Or I alloy the said copper by adding to one hundred pounds thereof
one half-ounce of regulus of zinc, and one half-ounce of grain or block tin, and
one ounce of regulus of antimony, and two ounces of regulus of arsenic; or
by adding thereto one ounce of zinc and one ounce of tin, or one ounce of
zinc and two ounces of antimony, or one ounce of zinc and four ounces of
arsenic; or by adding thereto one ounce of tin and two ounces of antimony, or

page_text: one ounce of tin and four ounces of arsenic; or by adding thereto two ounces
of antimony and four ounces of arsenic. I further declare that all the afore-
said alloys, or any of them, may be added to the said copper, either before or
after the said copper is melted; but I prefer the latter mode, because, when
the alloy is added before the said copper is in fusion, à larger quantity of alloy
is requisite on account of the greater destruction or waste thereof by oxidation
or by volatilization during the process of melting. Or I introduce the afore-
said alloys, or any of them, during the process which takes place after the
smelting of the copper, and which process is commonly called the toughening
or refining process. In this case it is best to add the alloy to the fused metal
after the same has been covered with charcoal in the usual manner, as the
charcoal affords some protection against oxidation. The common process of
poling then takes place, which serves to mix the alloy or alloys with, or to
diffuse the same through the copper, which is then examined by assay in the
way usually employed for ascertaining whether copper is properly toughened
or refined. If the alloy has been burnt out or dissipated during the process
(an accident which very rarely occurs), the assay on being broken will exhibit
the usual well known appearance of toughened or refined copper; but if, on
the contrary, the alloy is then in excess, the assay will exhibit on being broken
what the workmen call a toothy fracture, a species of fracture which serves to
denote that the metal has not yet acquired that fibrous texture which it is the
object of my said Invention to communicate to it. To correct such excess of
alloy in the aforesaid process or processes, I withdraw the charcoal from the
surface of the melted metal, and allow a stream of common air to pass over
the said surface, as is now the case with the smelters or refiners of copper
when they apprehend the metal is what some of the workmen call overheated.
By this exposure of the metal to the common air the oxygen of the latter
uniting with the said alloy reduces its quantity. To facilitate the oxygenation
of the said alloy the metal is agitated or put in motion by an iron rabble, which
process is commonly called flapping the metal, the operator from time to time.
examining the quality of the metal until it is found by the assay that the mass
has assumed that fibrous texture which it is the object of my said Invention
to communicate. Should the copper after this process be still found to contain
too much alloy, the excess may be compensated for by adding thereto some.
toughened or refined copper, as more particularly described hereafter. I have
also to state, that besides employing the means in common use for ascertaining
by assay the strength and quality of my improved copper, as before mentioned,
I further try its quality by casting perpendicularly in an iron mould a bar of
about six inches long, one inch thick, and two inches broad, which bar, when

page_text: cooled by immersion in water, is notched by a chisel to the depth of about one
eighth of an inch, at about an inch and quarter or half from the lower end of
the said bar and then placed in a vice to the depth of the said notch, with the
pouring end of the said bar upwards. Under these circumstances, if the
metal has been properly alloyed and refined, it will, when compared with
'common toughened or refined copper cast in the same mould and notched and
broken in the same manner, generally be found of such strength as to stand about
twice the number of blows of a light sledge hammer to tear or break it that
will be required to break copper that has been toughened or refined in the same
manner, and treated in every respect the same, excepting only what relates to
the alloying thereof, as above described; for example, should the said alloyed
copper require from sixteen to twenty blows, according to the weight of the
hammer, and the strength with which it is applied, the common refined copper
similarly treated will break with eight or ten such blows, or perhaps with
fewer; or should the alloyed copper require about forty blows, common copper,
that has in every respect been treated the same, excepting only what relates to
the addition of the alloy, will not probably resist more than half the number
of similar blows. I have thus given the general result of the last process for
trying the strength of the alloyed metal, but at the same time it must be
evident that it is a mere approximation to its actual strength as compared with
the strength of common toughened or refined copper, as the number of the
blows must in some degree depend upon the depth of the notch in the bar
cast for trial, the weight of the hammer used, and the strength of the person
applying it. The alloyed metal thus ascertained to have acquired its fibrous
texture and strength is then withdrawn from the furnace in the usual way.
I further declare, that although I have herein-before given the proportions of
copper and of alloy or alloys which experience has taught me to consider as
well adapted to give effect to my said Invention, yet I do not strictly confine
myself to such proportions, as they may be increased or diminished to some
extent at the discretion of the operator, regard being had to the object to be
attained, which is to give to the copper a more fibrous texture than it hereto-
fore possessed; but speaking generally, I would rather increase than diminish
the quantity of alloy, especially of any of the more volatile of the said alloys,
as zinc, antimony, and arsenic, to allow for any unforseen delay that may occur
in the process, and because, 'by using a little delay, the excess of alloy may be
dissipated before the metal is withdrawn from the furnace. And I have also to
state generally, that owing to differences in the construction of the furnaces,
and especially in the size of their flues, some of them may cause a greater waste
of alloy than others.

page_text: And I further declare, that if the copper to be improved has been
previously alloyed in excess, then I improve it by adding thereto tough-
ened or refined copper to bring the whole mass to the required fibrous
texture, which result is ascertained by the said process of assay and trial
herein-before mentioned. But if, from the uncertainty as to the quantity of
alloy in the previously alloyed copper, any small excess of alloy (with reference
to the object of my said Invention) should on such assay and trial still be
found, it is corrected by the introduction of an additional quantity of toughened
or refined copper, or by allowing a stream of air to pass over the surface of the
melted mictal as herein-before mentioned. If, however, the melted metal should
be found by the assay and trial to possess too small a portion of alloy, more
of the copper that has been previously alloyed in excess is added till the whole
mass is found, by assay and trial as aforesaid, to have attained the requisite
fibrous texture, which is the object of my said Invention.
And I further declare, that though in the method of operating first above
mentioned, I alloy toughened or refined copper in the manner that has been
described, yet the mere alloying of copper with other metal is not what
constitutes my said Invention, or what is claimed by me as such, for the alloying
of copper for some particular purposes, as for making common brass and gun
metal, has long been practised, but that my said Invention consists in communi-
cating, as before stated, to toughened or refined copper a degree of tenacity or
fibrous texture which it does not in its common state possess, and which I effect
by employing alloy or alloys in the manner that has been described, taking care
to avoid excess of alloy, for if added in excess the texture of the alloyed metal
will not be of that fibrous quality which it is the object of my said Invention to
communicate to it to enable it the better to resist the action of the sea water.
And I further declare, that the mere addition of toughened or refined copper
to copper that has been over alloyed, as described in the second method of
operating above mentioned, is not what constitutes my said Invention, but the
bringing thereby the alloyed metal to which the toughened or refined copper
is directed to be added to that fibrous state, which is produced by alloying
toughened or refined copper in the manner first directed.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, the Thirteenth day of December, in the year of our
Lord One thousand eight hundred and twenty-three.
ROBERT (L.s.) MUSHET.

page_text: AND BE IT REMEMBERED, that on the same Thirteenth day of
December, in the year above mentioned, the aforesaid Robert Mushet came
before our Lord the King in His Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained, in form above
written. And also the Specification aforesaid was stamped according to the 5
tenor of the Statute in that case made and provided.
ITANVTY 'S'O