IMPROVEMENTS IN COATING WITH METAL THE SURFACE OF ARTICLES FORMED OF METAL OR METALLIC ALLOYS
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME I JOHN
STEPHEN WOOLRICH of Birmingham in the County of Warwick Chemist
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria by. Her
Letters Patent under the Great Seal of Great Britain bearing date at West-
minster the First day of August in the sixth year of Her reign did for
Herself Her heirs and successors give and grant unto me the said John
Stephen Woolrich my exors admors and assigns Her especial license full
power sole privilege and authority that I the said John Stephen Woolrich
my exors admors or assigns and such others as I the said John Stephen
Woolrich my exors adiñors and assigns should at any time agree with
and no others from time to time and at all times hereafter during the term
of years therein expressed should and lawfully might make use exercise
and vend within that part of Her Majesty's United Kingdom of Great
Britain and Ireland called England Her Dominion of Wales and the Town
of Berwick-upon-Tweed my Invention of "IMPROVEMENTS IN COATING WITH
METAL THE SURFACE OF ARTICLES FORMED OF METAL OR METALLIC ALLOYS" in
which said Letters Patent there is contained a proviso that I the said John
Stephen Woolrich shall cause a particular description of the nature of my said
Invention and the manner in which the same is to be performed 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
18551-1,

page_text: in part recited Letters Patent as in and by the same reference being there-
unto had will more fully and at large appear.
NOW KNOW YE that in compliance with the said proviso I the said
John Stephen Woolrich do hereby declare that the nature of my said In-
vention and the manner in which the same is to be performed are fully
described and ascertained in and by the following Specification thereof reference
being had to the Drawings hereunto annexed and to the figures and letters
marked thereon (that is to say):-
My Improvements in Coating with Metal the Surface of Articles formed
of Metal or Metallic Alloys consists in the employment of a magnetic ap-
paratus in combination with metallic solutions and my mode of operation is
herein-after particularly described. The magnetic apparatus which I have
employed for that purpose is shewn in the Drawing.
Figure 1 is a plan Figure 2 a side elevation and Figure 3 an end
elevation drawn to a scale of one half the full size. The same letters are
used to denote the same parts on each Figure. The magnetic apparatus
is in part composed of a compound horseshoe magnet A Figures 1 and 2
placed in an horizontal position on a wooden platform or table and when
adjusted it must be firmly affixed thereto. An armature D D is fixed to a
spindle or shaft C C (Figure 1) the spindle or shaft revolves in bearings (a a).
A wheel E is fixed upon the spindle or shaft and is employed to give otary
motion to the shaft and of course to the armature which is thus made to
revolve before the poles P P of the magnet A A Figures 1 and 2. The
armature is made by binding a flat soft iron bar (shewn at Figure 4 E. D.
DE) which must be attached to the spindle or shaft C. About fifty yards of
copper wire of about one tenth of an inch thick covered with silk thread is
wound in a spiral direction round each end of the armature. One of the
covered wires is began to be wound from the end 6 of the wire Figure 1 and
continued towards the poles P P of the magnet and thence backwards and
forwards ending at c. The other covered wire is began to be wound on the
other end of the armature at 2 and wound towards the end D of the
armature in the direction from the poles of the magnet and thence forwards
and backwards ending at c where the two ends of the wires must be joined
together by solder. To the armature D I affix by two screws e e what I
call a dividor which is shewn of the real size at Figures 6. 7. and 8. The
dividor is composed of a brass tube y at one end of which is rivetted a piece
of brass (f) as a means of affixing the dividor to the armature as shewn
at Figure 1. At the other end a cylinder of boxwood g is affixed. A
piece of copper of the form shewn at Figure 8 is screwed to each
end of the cylinder of boxwood and it will be seen by examining Figures

page_text: 7 and 8 that each piece of copper h h is rather less than the segment
of a circle. One end d (Figure 1) of the covered copper wire is connected
to the piece of copper at one end of the cylinder of boxwood and the
end of wire b (Figure 1) is connected to the piece of copper at the
other end of the cylinder of boxwood. Four brass springs W X Y Z
are attached by screws to the upper parts of four brass pillars each pillar
being fixed at its bottom end into a wooden table or platform upon which
the compound magnet is fastened as before mentioned. These springs are
so adjusted as that while two of the springs W and Z are pressing on the
two pieces of copper h h one of which pieces of copper is affixed to one
end of the cylinder of boxwood and the other piece of copper to the other
end of the cylinder of boxwood in the manner herein-before described) the
other springs X and Y are pressing on the cylindrical surface of the box-
wood, and vice versa. Near the bottom end of each pillar a hole is drilled and
a piece of copper wire of about one tenth of an inch in diameter is passed
through the holes of the two pillars on each side of the dividor and is secured
to each pillar by a binding screw as shewn at T Figures 1. 2. 3. and at U
Figures 1 and 3.
When I desire to coat with metal the surface of articles formed of metals
or metallic alloys, I place an earthenware vessel containing a solution (pre-
pared as herein-after described) as near as may be convenient to the wires
T and U. The article to be coated with metal should be well cleaned and
then should be brought into contact with the wire T and a plate of metal
similar to the metal of which the metallic solution is partly composed must
be brought into contact with the wire U. The article to be coated with metal
must be immersed in the solution contained in an earthenware vessel and
the plate of metal connected to the wire U should be previously either wholly
or partially immersed in the solution the portion of the superficies of the
plate to be immersed depending upon the relation of the same to the super-
ficies of the article to be coated. Care must be taken that the article to be
coated with metal and the metal plate do not touch though they should be
placed near to each other. A screw S Figure 1 is used to adjust the distance
between the poles P P of the magnet and the ends of the armature D. The
magnetic apparatus being in the position shewn in the Drawings Figures 1. 2
and 3 and all other things being adjusted as herein-before is mentioned rotary
motion is communicated by a band to the wheel E and consequently to the shaft
CC (Figure 1), and to the armature D D and to the coils of covered wire
B B and also to the dividor G. I have generally given to the shaft C C about
seven hundred complete revolutions per minute and the distance between the

page_text: ends of the armature and the poles of the magnet may vary from three
inches to one hundredth part of an inch the latter being the nearest practicable
distance for revolution, the weight of metal deposited in a certain time on
the surface of articles formed of metal or metallic alloys will vary as the
distance varies between the ends of the armature and the poles of the
magnet-the weight of metal deposited will also vary as the number of revolu-
tions of the armature varies and also with the weight of the metal contained
in a given volume of the metallic solution in which the article to be coated
'is immersed.
The solutions which I use are made in the following manner I take of
the best pearlash of commerce twenty-eight pounds (avoirdupois) and add
to it thirty pounds (avoirdupois) of water and boil them in an iron vessel
until the pearlash is dissolved the solution should then be poured into an
earthenware or other suitable vessel and suffered to stand until the liquid becomes
cold. It should then be filtered and fourteen pounds (avoirdupois) of distilled
water added thereto. Sulphurous acid gas (obtained by any of the known
processes should then be passed into the filtered liquor until it is saturated
taking care not to add sulphurous acid gas in excess the liquor should be
again filtered and the liquor so filtered is what I term the solvent or sulphite
of potash.
To make the silvering liquor which I use in coating with silver the surface
of articles formed of metals or metallic alloys I dissolve twelve ounces
(avoirdupois) of crystallized nitrate of silver in three pounds of distilled water
(in a clean earthenware vessel) and add to the solution by a little at a time
the before-mentioned solvent so long as a whitish-coloured precipitate is
produced (care being taken not to add more of the solvent than is necessary).
After the precipitate has subsided I pour off the supernatant liquor and
wash the precipitate with distilled water. To the precipitate I add as much
of the before-mentioned solvent as will dissolve it and afterwards add about
one sixth part more of the solvent so that the solvent may be in excess.
I then stir them well together and let them remain about twenty-four hours
and then filter the solution when it will be ready for use. This is what I
designate silvering liquor.
To make the gilding liquor which I use in coating with gold the surface of
articles formed of metal or metallic alloys I dissolve four ounces (troy) of
fine gold in a mixture of eleven fluid ounces of nitric acid (specific gravity 1.45)
and thirteen fluid ounces of muriatic acid (specific gravity 1.15) and twelve
fluid ounces of distilled water. I then evaporate the solution and crystallize.
I then take the crystals and dissolve them in one pound of distilled water

page_text: and precipitate the gold by pure magnesia. I then wash the precipitate
firstly with distilled water acidulated with nitric acid and afterwards with
distilled water alone and then add to the washed precipitate so much of
the before-mentioned solvent or sulphite of potash as will dissolve the pre-
cipitate. I then add about one fifth part more of the solvent so that the
solvent may be in excess. I then stir them well together and let them
remain about twenty-four hours and then filter the solution when it will be
ready for use. This is what I designate gilding liquor.
To make the coppering liquor which I use in coating with copper the
surface of articles formed of metal or metallic alloys I dissolve seven pounds
(avoirdupois) of the crystals of sulphate of copper in thirty pounds of distilled
water and add to this solution a solution of carbonate of potassa in water
until precipitation ceases. I then filter and collect the precipitate and wash
it with distilled water and put it in a clean earthenware vessel. I then add
to it as much of the before-mentioned solvent as will dissolve the precipitate
and afterwards add one third more of the solvent so that the solvent may be
in excess. I then stir them well together and let them remain about twenty-
four hours and then filter the solution when it will be ready for use. This
is what I designate coppering liquor.
The thickness of metallic coating to be deposited on the article intended
to be coated will depend on the time during which the article is submitted
to the operation of the magnetic apparatus and solution a thin coating will
be deposited in a few seconds, whilst to obtain a thick coating the article
must be submitted to the constant operation of the magnet and solution for
several hours.
To adjust the magnetic apparatus for operation it will be requisite to
ascertain which of the two copper wires T and U should be connected to
the article to be coated. I ascertain it as follows I put the magnetic
apparatus in motion and then pass the ends of both the copper wires T and U
into water acidulated with sulphuric acid when if the magnetic apparatus
is in proper working order gas will be given off at one of the wires only
to which wire I connect the article to be coated and I connect the other
wire to a metal plate as before described. When the surface of the article to
be coated is not of metal or metallic alloys I give to it a metallic surface by
rubbing plumbago upon it and I then coat with metal the plumbago surface
by the method herein-before described.
The distance at which the poles of the magnet should be placed from the
ends of the armature will depend upon the superficies of the article to be
coated. The larger the superficies of the article the nearer must the magnet

page_text: be placed to the armature and the smaller the article the greater must the
distance be encreased, the distance being inversely as the superficies of the
article to be coated. If the surface of the article to be coated with metal
becomes while in connection with the magnetic apparatus of a brownish or
darkish appearance or if gas be evolved from the surface of the article during
the operation the magnet must be adjusted by the screw S Figure 1 so
as to encrease the distance between the poles of the magnet and the
ends of the armature until the metal contained in the solution is properly
deposited.
Having now described by this my Specification the nature of my said In-
vention and the manner in which the same may be performed I claim as my
Invention the Method of Coating with Metal the Surface of Articles formed
of Metal or Metallic Alloys by means of magnetic apparatus in combination
with metallic solutions..
And I also claim the application of solutions in water of that class of
salts known to chemists as the sulphites for dissolving the preparations of silver
gold and copper for the purpose of coating with metal the surface of articles
formed of metal or metallic alloys.
In witness whereof I have hereunto set my hand and seal this First
day of February in the year of our Lord One thousand eight hundred
and forty-three.