- DISCLAIMER AND MEMORANDUM OF ALTERATION.
Year: 1869

page_text: THE PLATING COMPANY LIMITED.-
DISCLAIMER AND MEMORANDUM OF ALTERATION.
Filed 24th June 1873.
[BROOKES' PATENT.]
In the Matter of the Letters Patent granted to WILLIAM BROOKES, of
62, Chancery Lane, in the County of Middlesex, Civil Engineer and Patent
Agent, for the Invention of "IMPROVEMENTS IN THE ELECTRO-DEPOSITION
OF NICKEL." A communication from abroad by Isaac Adams, junior,
of Boston, Massachusetts, in the United States of America, bearing date
the 28th day of October 1869, and Nod. 3125.
DISCLAIMER AND MEMORANDUM OF ALTERATION proposed by the
Plating Company, Limited, having their Registered Office at 34, Kirby Street,
Hatton Garden, in the County of Middlesex, to whom the said Letters Patent
have been assigned, and who are duly registered as the Proprietors thereof,
to be filed in the Great Seal Patent Office, with the Specification to which
the same relates, according to the Statute in that case made and provided.
WHEREAS since the date of the said Letters Patent, and of the filing of the
Specification thereof by the said William Brookes, and also since the said Letters
Patent were assigned to the said Company, it has been ascertained that the claims
as made are too large, and may be construed to include more than is properly com-
prised within the Invention intended to be patented, and it is desired to limit the
said claims and amend the same in the manner herein-after set forth.
NOW KNOW YE, that the Plating Company Limited, by and with the leave
of Her Majesty's Attorney General, do hereby, for the reasons aforesaid, introduce the
words "as above described" in line 35, page 10, of the said Specification, as printed
by Her Majesty's Printers, after the word "prepared," and before the word "and,"
and also introduce the words "for the purposes above set forth," in the same line,
after the word "used," and before the word "in," and the said Plating Company,
Limited, hereby disclaim the 3rd, 4th, and 5th claims, set out in the 11th page of
the said Specification, as printed by Her Majesty's Printers.
And in order that the effect of the present Disclaimer and Memorandum of
Price 6d1

page_text: Alteration may be clearly shown and understood, the said Plating Company,
Limited, will proceed to recite (omitting the preamble and testing clause) the said
Specification as proposed to be hereby amended:-
"
It has long been well known that nickel possesses certain qualities which
"would render it of great value in the arts if it could be readily and surely
deposited by the battery in such a manner as to make those qualities available.
"These qualities are, first, its infusibility; second, its colour, which is nearly that
"of silver; third, its hardness, which is nearly equal to that of steel, and by
"reason of which it resists wear and abrasion to a much greater degree than silver;
fourth, its power of resisting oxidation and the tarnishing and corrosive effects
"of many gases and liquids. The two last named qualities render it for many
purposes greatly superior to silver, which it much resembles in appearance for
electro-plating other metals, and for making articles of solid metal. To these
"advantages should be added its cheapness as compared with silver.
"
"
"
"
"It has long been known that nickel could be deposited from certain solutions
by electricity, but the character of the deposits has been such that the valuable
qualities of the metal could not be secured to such an extent as to render it
practically useful for general purposes. The difficulties in the way of its de-
position have arisen mainly from the character of the solutions employed, and
"the nature of the nickel used for anodes in the depositing cell.
"
"
"
46
"The Inventor has discovered the causes of certain difficulties in the practical
deposition of this metal, and is able to remove them, and to point out methods of
preparing solutions and the conditions which they must satisfy, and under which
"they must be used, so that solid, coherent, tenacious, and flexible nickel can be
deposited to any desired amount. He can thus render the electro-deposition of
"nickel practically valuable, not only for electro-plating other metals, but for
"that branch of the art of electro-deposition known as electrotyping, that is, the
deposition of nickel upon a surface not to remain upon it as a permanent coating,
"but to be removed and used independently of it.
"
"The improvements relate, first, to the method of preparing certain solutions
" from which the nickel is to be deposited, and to the properties and conditions
"which such solutions must possess; second, to a method of preparing nickel plates for
"the anode of the depositing cell; third, to the character of the deposits obtained.
"In order to explain fully the nature of the Invention it is necessary to refer to
"certain facts relating to the electro-deposition of metals generally which have
"been long known.
"It is well known that metals are deposited in three conditions, vizt., first, as a
black powder; second, in a state called reguline metal, that is, in a condition
" which exhibits the ordinary qualities of the metal; third, in a hard crystalline
"condition.
"For most purposes in the arts it is necessary that the metals should be deposited
"in the reguline state, the applications which are made of the powdery or crystal-
line deposits being very few.
"
"
"
"There are two applications of the art of electro-deposition, which are usually
recognized as two distinct branches of the art, and which embrace nearly all its
practical uses. One is called electro-plating, and consists in depositing a coating
"of one metal upon another metal to remain upon it as a permanent coating. The
"other application is called electrotyping, and consists in depositing one metal
upon another, or upon a prepared surface of some other substance, from which it
" is to be used separately from the surface upon which the deposit is made.
"For each of these purposes the metal must be deposited in the reguline state.
removed to bo
"It has long been known that the metals differ greatly in the facility with
"which they can be deposited by the electric current, especially in the regu-
"line form, so also different solutions of the same metal differ greatly in respect to
"the deposits which may be obtained from them. With some solutions it is
"difficult, if not impossible, to obtain a deposit of reguline metal under any cir-

page_text: "cumstances. The difficulty seems in some cases to be inherent in the character
of the solution itself; in other cases it is due to the presence of foreign elements,
or temperature of the solution, or to the density
or to the density of the current employed. Different solutions also differ
"greatly in the amount of metal which can be deposited with a given strength of
"current. Some solutions give a deposit of metal which is the full chemical
"equivalent of the electricity passing through the solution, while others fall far
below it. Solutions also differ within wide limits in respect to the intensity and
"density of the current required to give a reguline deposit. The differences in
solutions in these respects are of great importance with reference to the cost of
"depositing the metals. The higher the intensity required to effect the deposition
"of the metal the greater the cost, and it is obvious that the cost of the deposit
"will increase in proportion as it falls short of the full amount due to the
"electricity passing through the solution.
"Another circumstance is of great importance in the depositing of metals. It
often happens that a thin film may be obtained of one metal upon another, but
"that the process of deposition cannot be carried on to such an extent as to obtain
"a coating of any appreciable thickness. As soon as the metal to be coated has
received a mere film, the conditions are so changed that the deposit is practically
stopped. A characteristic of this filmy deposit is, that though the particles of
"the metal adhere separately to the metal on which the deposit is made, the deposit
is so thin that the particles of the deposit have no such coherence among them-
"selves as will allow the deposit to be removed from the surface on which it is
deposited, nor will such a deposit afford any substantial protection against
"abrasion or the ordinary wear to which most plated articles are subjected, nor to
"the action of corrosive agents. It is obvious therefore that it is impossible to
"make electro-types plates from such deposits, and that such deposits are practically
"useless for most purposes to which electro-plating is applied.
"
"
"Although it has long been known that nickel could be deposited to some extent
from various solutions, yet the Inventor believes that prior to his improvements
it has not been practicable to obtain deposits of such character and thickness as
are required for electro-typing, or even for most of the purposes of electro-
plating.
The solutions from which the nickel has been heretofore, most successfully
deposited are the Inventor believes the chloride of nickel, the cyanide of nickel
and potassium, the double sulphate of nickel and ammonia, and the double
"chloride of nickel and ammonium. Of these solutions as heretofore prepared the
"Inventor believes the chloride is the best, but the deposits obtained from it are
"very far from what is required for the general purposes to which the electro-
deposition of this metal may be applied. As this solution is ordinarily prepared
"it is a good conductor of electricity as compared with most liquids, and the nickel
"is deposited from it freely, but in a spongy, brittle condition, and more or less
"mixed with the peroxide of nickel, which gives it a brownish appearance. The
"deposit has also a great tendency to accumulate on the edges of the plate on
which it is made in nodules or warty protuberances. Therefore although the
deposits may be obtained of considerable thickness they are practically useless for
"electro-typing or electro-plating. Moreover a portion of the electricity is expended
"in forming a sub-chloride of nickel which falls to the bottom of the vessel as an
insoluble precipitate. In consequence of this the solution is soon exhausted both
"of nickel and chlorine, and the process of deposition stops. Even when the solu-
"tion is formed in the best known manner by subliming a pure nickel chloride the
"deposited metal though free from the oxide, and therefore white, is deposited in
"brittle, warty condition, accompanied with the precipitation of the sub-chloride.
"The double cyanide of nickel and potassium is a poor conductor of electricity, and
"requires a high battery power. With a low battery power very little metal can
"be deposited, and that little is accompanied with the deposition of peroxide of
"nickel to such an extent as to be black or nearly black." With a high battery
P. 801. W. 13487.

page_text: "
"
power a film of white nickel may be obtained, but not thick enough to satisfy
"the ordinary requirements of electro-plating. Neither of these solutions, so far
as the Inventor has seen them used, gives for any great length of time the full
equivalent of metal for the electricity employed, and so far as he has been able to
"discover these two solutions are inherently incapable of giving a coherent
"tenacious flexible metal such as is required in the arts of electro-typing and electro-
"plating. Of the other two solutions named the Inventor believes that before his
improvements the best results were obtained from the double chloride of nickel
and ammonium, but the metal deposited from it is of such a character as to be
"worthless when deposited to any appreciable thickness. It is accompanied with
"the deposit of peroxide, and is therefore black or brown. It is extremely liable
"to split up into thin scales, which may be rubbed off even with the hand. This
"want of coherence and tenacity unfits it for the requirements of the arts.
"metal deposited from the double sulphate of nickel and aminonia is substantially
"the same as the above, but it is not so easily obtained. If with these solutions a
"battery power is used of an intensity of two Grove cells or thereabouts a white
deposit may be obtained of considerable thickness, but still with such a tendency
"to split up in scales that it is practically useless, and neither solution gives the
"full equivalent due to the current. The Inventor has discovered however that
"the difficulties attending the use of these last named solutions, and the character
"of their deposits, are not inherent in the nature of the solutions, but are due to
"the modes of preparing them or to the presence in minute quantities of certain
"substances which are generally and he believes universally employed in making
them, or in the reduction of the nickel used in making them. In order there-
"fore to prepare these solutions in such a manner as to give the results reached it
"is necessary to adopt processes in their preparation and observe precautions which
"shall either dispense with the use of these substances altogether or shall effectually
"remove them if they are employed, and which are wholly unnecessary in their
preparation for any other use with which the Inventor is acquainted.
"
"
In preparing this solution the Inventor prefers to use pure nickel, but com-
"mercial nickel may be used. Commercial nickel almost always contains more or
"less of the reagenta employed in the purification or manufacture of the metal,
"such as sulphate of lime, sulphide of calcium, sulphide of sodium or potassium,
chloride of sodium and alumina. When any of these substances are present it is
"necessary to remove them; this can be done by melting the nickel or by boiling
"it in water containing at least one per cent. of hydrochloric acid. The boilings
"must be repeated with fresh acid and water until the wash waters give no indi-
"cation of the presence of lime when treated with oxalate of ammonia. When the
"metal is purified by melting the foreign substances collect on the top of the melted
"metal in the form of a slag, which can be removed mechanically. If the nickel
" contains zinc it should be melted in order to volatilize the zinc, and drive it off.
"The crucible in such case must not be closed so tightly as to prevent the escape
"of the zinc fumes. If copper, arsenic, or antimony is present in the nickel it can
be removed after the nickel is dissolved by passing sulphuretted hydrogen through
"the solution. The acid to be used in dissolving the metal consists of one part
strong nitric acid, six parts muriatic acid, and one part water. Nitric acid or
"muriatic acid may be used separately, but the above mixture is preferred. A
"quantity of this acid is taken, sufficient to dissolve any given amount of the
"metal with as little excess of the former as possible; a gentle heat is all that is
"required. The resulting solution is then filtered, and to prepare the solution of
"the double sulphate of nickel and ammonia a quantity of strong sulphuric acid
"sufficient to convert all the metal into sulphate is added, and the solution is then
" evaporated to dryness. The mass is then again dissolved in water and a much
smaller quantity than before of sulphuric acid is added, and the whole again.
" evaporated to dryness, the temperature being raised finally to a point not to
"exceed 650° Fahrenheit. This temperature is to be sustained until no more
vapors of sulphuric acid can be detected. The resulting sulphate of nickel is
"

page_text: "pulverized and thoroughly mixed with about one fiftieth (3) of its weight of
"carbonate of ammonia, and the mass again subjected to a gradually increasing
temperature not to exceed 650° Fahrenheit until the carbonate of ammonia is
"entirely volatilized. If any iron is present the most of it will be converted into
"an insoluble salt, which may be removed by filtration. The resulting dry and
"neutral sulphate of nickel is then dissolved in water by boiling, and if any
"insoluble residue remains, the solution is filtered. From the weight of the nickel
"used before solution the amount of sulphuric acid in the dry sulphate can be
"calculated. This amount of sulphuric acid is weighed out diluted with four times
"its weight of water and saturated with pure ammonia or carbonate of ammonia;
is
the former is preferred. This solution if it, at all alkaline should be evaporated
"until it becomes neutral to test paper. Tho sulphate of ammonia of commerce
"may likewise be used, but pure sulphate of ammonia is to be preferred. The two
"solutions of the sulphate of nickel and sulphate of ammonia are then united and
"diluted with sufficient water to leave one and a half to two ounces of nickel to
"each gallon of solution, and the solution is ready for use. The object of twice
" evaporating to dryness and raising the temperature to so high a degree is in the
"first place to drive off the excess of sulphuric acid, and secondly, to convert the
sulphate of iron if it exists into basic sulphate which is quite insoluble in
"water.
"In order to give the best results it is necessary that the solution should be as
"nearly neutral as possible, and it should in no case be acid. The Inventor prefers
to use the solution of a specific gravity of about 1052 (water 1000), though a
much weaker or a still stronger solution may be used. At temperatures above.
"the ordinary the solution still gives good results, but is liable to be slowly devom-
"posed. An excess of sulphate of ammonia may be used to dilute the solution in
"cases when it is desirable to have it contain much less than an ounce of nickel to
"the gallon.
."
In preparing the solution of the double chloride of nickel and ammonium the
"nickel is to be purified and dissolved in the same manner as is described for the
previous solution, and it is to be freed from copper and other foreign matters in
"the same manner. The solution is then to be evaporated to dryness; it should
"be made as nearly anhydrous as possible. The salt is then placed in a retort and
"heated to a bright red heat. The salt sublimes and is collected in a suitable
"receiver, the earthly matter being left behind. The salt thus purified is dissolved
"in water and to the solution is added an equivalent quantity of pure chloride of
"ammonium. The solution is then ready for use, it may have a specific gravity
"of 1050 to 1100. Of these two solutions the Inventor much prefers the double
"sulphate as it gives a softer metal which can be polished or otherwise worked
"nore readily than that obtained from the double chloride solution. The double
sulphate solution has this important advantage over any other solution with which
"I am acquainted that it gives a deposit with a smooth surface which can be
"polished with comparatively little labour. When the process is properly con-
ducted the deposit can be made much thicker than is ordinarily required for
plating other metals before it acquires a rough or matted surface. With a metal
"so hard as nickel this is a matter of great importance.
"
"Another important part of the Invention is the preparation of the nickel
"plates to be used as anodes in the depositing cells. Almost all commercial
"nickel contains more or less copper, zinc, and arsenic, and the complete removal
"of all these metals would be a matter of great difficulty and expense, and yet it
"is necessary to remove them or in some way counteract or neutralize their
"influence. When these metals are present they are to some extent deposited
"with the nickel and seriously affect the character of the deposited nickel. Copper
"impairs its color and has a tendency to produce a gray hard deposit less tenacious
and coherent than pure nickel, more easily turnished and hard to polish. A very
"small amount of arsenic makes the nickel tarnish readily in the air. Zinc affects

page_text: "the deposited metal in much the same way as copper, and it also tends to cause
"the evolution of hydrogen at the cathode or negative polo, and thus interferes
"with the deposition of the nickel.
"
"
from
The Inventor has discovered that in his improved solutions the depositions of
copper and arsenic when present with the nickel may be effectually prevented
"by combining iron with the nickel. The iron itself is almost wholly precipitated
"as a peroxide and is not deposited with the nickel to a sufficient extent to injure
"the character of the deposit, neither does it injuriously affect the solution. The
"effect of the iron upon the copper is either to prevent it being dissolved or if
"dissolved to immediately reduce it upon the anode, where it forms a coating,
"which may be removed from time to time by scraping. The arsenic forms an
"insoluble precipitate with the persalt of iron. The amount of iron which should
"be combined with the nickel will vary with the amount of copper and arsenic
"present, and should be as nearly as possible the chemical equivalent of the
"amount present of those metals. It can be combined with the nickel by intro-
ducing the proper quantity in small fragments into tho crucible in which the
"nickel is melted. Sometimes commercial nickel has sufficient iron present to
"counteract the influence of the copper and arsenic. When copper and zinc are
present to any considerable extent in nickel, it may be melted in a crucible and
"cast into plates for anodes without any serious difficulty, as it then melts at a
"temperature not much greater than the melting point of cast iron. The presence
of cast iron also facilitates the melting of nickel. Puro nickel is very hard to
"melt, but it may be melted without much difficulty by introducing into the
"crucible carbon in a finely divided state, or silica or both, and tho presence of
"these substances in the nickel does not injure the solution. It is necessary to
"melt commercial nickel not only to cast it into plates for anodes and combine it
"with iron when copper and arsenic are present, but to remove any potash, soda,
lime, or alumina left adhering to it in the process of reduction, these substances
being removed as before stated as slag. Whon zinc is present it will be removed
to a great extent in the process of melting by volatilization unless the melting is
"done in a tight vessel.
"6
"
Having prepared the solutions and anodes as herein described, nickel may be
readily deposited, but in order to carry on the deposition continuously it is
"necessary to observe certain precautions."
First. The use of,a battery of too high an intensity must be avoided, an
intensity of two Smee cells is sufficient. A high intensity decomposes the
"solution and liberates free ammonia, thus rendering the solution alkaline and
"impairing its value. Whenever the smell of free ammonia arises from the decom-
"posing cell the operator may be certain that the solution is being injured. It is
important that the depositing shall not be forced by the use of too strong a
" current.
"Second. It is important that great precaution should be used to prevent the
"introduction into the solution of even minute quantities of potash, soda, or nitric
"acid. When an article to be coated is cleaned in acid or alkaline water or is
"introduced into it for any purpose the greatest care must be taken to remove all
"traces of these substances before the article is introduced to the nickel solution as
the introduction of the most minute quantities of acids or alkalies will surely be
injurious. It is important that the solution be kept free from all foreign sub-
stances, but its purity from those above named is especially important.
"Third. The anode of the depositing cell should present a surface to the action
"of the solution somewhat larger than the surface upon which the deposit is being
"made, particularly in the double sulphate solution. The reason is that nickel
"dissolves so slowly that if the exposed surface is not larger than the surface on
which the deposit is made the solution will not keep saturated. On the other
"hand if the anode is very much larger than the positive pole it tends to give a
"deposit of black powder.

page_text: "Fourth. If zinc is to be coated it should first be coated with copper, as it is
difficult to make nickel adhere to zinc, and there is danger that the zinc may be
acted on and injure the solution. With solutions and anodes thus prepared and
used the deposition of nickel can be carried on continuously and almost as surely
and certainly as the deposition of copper from the common sulphate solution
though the limits of the battery power which may be used are narrower. The
metal deposited is compact, cohesive, and tenacious. It may be deposited of
"nearly uniform thickness over any surface however large. The deposited metal
"is capable of being annealed by a heat below a red heat; it then becomes
"flexible, malleable, and ductile. The deposit may be made of any required
thickness, either to furnish effectual protection to the metal on which it is
deposited, or to be removed and used separately from the surface on which it may
be deposited. Thus electrotype plates of nickel may be produced, either as copies
"of irregular surfaces which it is desired to reproduce, or as plain sheets of nickel,
"which after being annealed may be rolled, hammered, or spun into a variety of
ar
"forms, of articles.
low
"The solutions also give the full equivalent of nickel for the electricity em-
"ployed.
"The Inventor believes deposits possessing these qualities were never produced
"except by means of these his improvements, I therefore claim,―
"First. The electro-deposition of nickel by means of a solution of the double
"sulphate of nickel and ammonia, or a solution of the double chloride of nickel
"and ammonium prepared as above described, and used for the purposes above set
"forth, in such a inanner as to be free from the presence of potash, soda, alumina,
lime, or nitric acid, or from any acid or alkaline reaction.
"Second. The use for the anode of a depositing cell of nickel combined with iron
"to prevent the copper and arsenic which may be present froin being deposited
"with the nickel, or from injuring the solution."
In witness whereof, the said Plating Company, Limited, have hereunto caused
their common seal to be affixed, this Thirtieth day of May One thousand
eight hundred and seventy-three.

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the
County of Middlesex, Civil Engineer and Patent Agent, for the
Invention of "IMPROVEMENTS IN THE ELECTRO-DEPOSITION OF NICKEL."-
A communication from abroad by Isaac Adams, jun'., of Boston,
Massachusetts, in the United States of America.
Sealed the 14th January 1870, and dated the 28th October 1869
COMPLETE SPECIFICATION filed by the said William Brookes at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 28th October 1869, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BROOKES, of 62, Chancery Lane, in the County of Middlesex, Civil
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE ELECTRO-DEPOSITION OF NICKEL," Com-
municated to me from abroad by Isaac Adams, jun"., of Boston, Massa-
chusetts, in the United States of America, and in what manner the same

page_text: is to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say :-
It has long been well known that nickel possesses certain qualities
which would render it of great value in the arts if it could be readily and
surely deposited by the battery in such a manner as to make those qualities
available. These qualities are, first, its infusibility; second, its colour,
which is nearly that of silver; third, its hardness, which is nearly equal
to that of steel, and by reason of which it resists wear and abrasion to a
much greater degree than silver; fourth, its power of resisting oxidation
and the tarnishing and corrosive effects of many gases and liquids. The
two last-named qualities render it for many purposes greatly superior to
silver, which it much resembles in appearance, for electro-plating other
metals and for making articles of solid metal. To these advantages
should be added its cheapness as compared with silver.
It has long been known that nickel could be deposited from certain
solutions by electricity, but the character of the deposits has been such
that the valuable qualities of the metal could not be secured to such an
extent as to render it practically useful for general purposes. The
difficulties in the way of its deposition have arisen mainly from the
character of the solutions employed and the nature of the nickel used
for anodes in the depositing cell.
The Inventor has discovered the causes of certain difficulties in the
practical deposition of this metal, and is able to remove them and to
point out methods of preparing solutions and the conditions which they
must satisfy, and under which they must be used, so that solid, coherent,
tenacious, and flexible nickel can be deposited to any desired amount.
He can thus render the electro-deposition of nickel practically valuable,
not only for electro-plating other metals, but for that branch of the art
of electro-deposition known as electrotyping, that is, the deposition of
nickel upon a surface not to remain upon it as a permanent coating, but
to be removed and used independently of it.
The improvements relate, first, to the method of preparing certain
solutions from which the nickel is to be deposited, and to the properties
and conditions which such solutions must possess.
Second. To a method of preparing nickel plates for the anode of the
depositing cell.
Third. To the character of the deposits obtained.

page_text: In order to explain fully the nature of the Invention it is necessary to
refer to certain facts relating to the electro-deposition of metals generally
which have been long known.
It is well known that metals are deposited in three conditions, viz. :-
First, as a black powder; second, in a state called reguline metal, that
is, in a condition which exhibits the ordinary qualities of the metal;
third, in a hard crystalline condition.
For most purposes in the arts it is necessary that the metals should be
deposited in the reguline state, the applications which are made of the
powdery or crystalline deposits being very few.
There are two applications of the art of electro-deposition, which are
usually recognized as two distinct branches of the art, and which
embrace nearly all its practical uses. One is called electro-plating, and
consists in depositing a coating of one metal upon another metal to
remain upon it as a permanent coating. The other application is called
electrotyping, and consists in depositing one metal upon another, or
upon a prepared surface of some other substance, from which it is to be
removed to be used separately from the surface upon which the deposit
is made. For each of these purposes the metal must be deposited in the
reguline state.
It has long been known that the metals differ greatly in the facility
with which they can be deposited by the electric current, especially in
the reguline form; so also different solutions of the same metal differ
greatly in respect to the deposits which may be obtained from them.
With some solutions it is difficult, if not impossible, to obtain a deposit
of reguline metal under any circumstances. The difficulty seems in
some cases to be inherent in the character of the solution itself, in other
cases it is due to the presence of foreign elements or to the density or
temperature of the solution or to the density of the current employed.
Different solutions also differ greatly in the amount of metal which
can be deposited with a given strength of current. Some solutions give
a deposit of metal which is the full chemical equivalent of the electricity
passing through the solution, while others fall far below it. Solutions
also differ within wide limits in respect to the intensity and density of
the current required to give a reguline deposit. The differences in
solutions in these respects are of great importance with reference to the
cost of depositing the metals. The higher the intensity required to

page_text: effect the deposition of the metal the greater the cost, and it is obvious
that the cost of the deposit will increase in proportion as it falls short of
the full amount due to the electricity passing through the solution.
Another circumstance is of great importance in the depositing of
metals. It often happens that a thin film may be obtained of one metal
upon another, but that the process of deposition cannot be carried on to
such an extent as to obtain a coating of any appreciable thickness. As
soon as the metal to be coated has received a mere film the conditions
are so changed that the deposit is practically stopped. A characteristic
of this filmy deposit is that though the particles of the metal adhere
separately to the metal on which the deposit is made the deposit is so
thin that the particles of the deposit have no such coherence among
themselves as will allow the deposit to be removed from the surface on
which it is deposited, nor will such a deposit afford any substantial
protection against abrasion or the ordinary wear to which most plated
articles are subjected, nor to the action of corrosive agents. It is obvious
therefore that it is impossible to make clectrotype plates from such
deposits, and that such deposits are practically useless for most purposes
to which electro-plating is applied.
Although it has long been known that nickel could be deposited to
some extent from various solutions, yet the Inventor believes that prior
to his improvements it has not been practicable to obtain deposits of
such character and thickness as are required for electrotyping, or even
for most of the purposes of electro-plating.
The solutions from which nickel has been heretofore most successfully
deposited are, the Inventor believes, the chloride of nickel, the cyanide
of nickel and potassium, the double sulphate of nickel and ammonia,
and the double chloride of nickel and ammonium. Of these solutions as
heretofore prepared the Inventor believes the chloride is the best, but
the deposits obtained from it are very far from what is required for the
general purposes to which the electro-deposition of this metal may be
.applied. As this solution is ordinarily prepared it is a good conductor of
electricity as compared with most liquids, and the nickel is deposited
from it freely, but in a spongy brittle condition, and more or less mixed
with the peroxide of nickel, which gives it a brownish appearance. The
deposit has also a great tendency to accumulate on the edges of the plate
on which it is made in nodules or warty protuberances. Therefore although
.the deposits may be obtained of considerable thickness they are practically

page_text: useless for clectrotyping or electro-plating. Morcover a portion of the
electricity is expended in forming a sub-chloride of nickel, which falls
to the bottom of the vessel as an insoluble precipitate. In consequence of
this the solution is soon exhausted both of nickel and chlorine, and the
process of deposition stops. Even when the solution is formed in the
best known manner by subliming a pure nickel chloride, the deposited
metal though free from the oxide and therefore white is deposited
in the brittle warty condition accompanied with the precipitation of
the sub-chloride. The double cyanide of nickel and potassium is a poor
conductor of electricity, and requires a high battery power. With a low
battery power very little metal can be deposited, and that little is
accompanied with the deposition of peroxide of nickel to such an extent.
as to be black or nearly black. With a high battery power a film of
white nickel may be obtained, but not thick enough to satisfy the
ordinary requirements of electro-plating. Neither of these solutions, so
far as the Inventor has seen them used, gives for any great length of
time the full equivalent of metal for the electricity employed, and so far
as he has been able to discover these two solutions are inherently
incapable of giving a coherent tenacious flexible metal such as is
required in the arts of electrotyping and electro-plating. Of the other
two solutions named the Inventor believes that before his improvements
the best results were obtained from the double chloride of nickel and
ammonium; but the metal deposited from it is of such a character as to
be worthless when deposited to any appreciable thickness. It is accom-
panied with the deposit of peroxide, and is therefore black or brown:
It is extremely liable to split up into thin scales, which may be rubbed
off even with the hand. This want of coherence and tenacity unfits it
for the requirements of the arts. The metal deposited from the double
sulphate of nickel and ammonia is substantially the same as the above,
but it is not so easily obtained. If with these solutions a battery power
is used of an intensity of two Grove cells or thereabouts a white deposit
may be obtained of considerable thickness, but still with such a tendency
to split up in scales that it is practically useless, and neither solution
gives the full equivalent due to the current. The Inventor has discovered
however that the difficulties attending the use of these last-named
solutions and the character of their deposits are not inherent in the
nature of the solutions, but are due to the modes of preparing them, or
to the presence in minute quantities of certain substances which are
generally and he believes universally employed in making them, or in

page_text: the reduction of the nickel used in making them. In order therefore to
prepare these solutions in such a manner as to give the results reached
it is necessary to adopt processes in their preparation and observe pre-
cautions which shall either dispense with the use of these substances
altogether or shall effectually remove them if they are employed, and
which are wholly unnecessary in their preparation for any other use with
which the Inventor is acquainted.
In preparing this solution the Inventor prefers to use pure nickel,
but commercial nickel may be used. Commercial nickel almost always
contains more or less of the reagents employed in the purification or
manufacture of the metal, such as sulphate of lime, sulphide of calcium,
sulphide of sodium or potassium, chloride of sodium, and alumina. When
any of these substances are present it is necessary to remove them.
This can be done by melting the nickel or by boiling it in water con-
taining at least one per cent. of hydrochloric acid. The boilings must be
repeated with fresh acid and water until the wash waters give no
indication of the presence of lime when treated with oxalate of ammonia.
When the metal is purified by melting the foreign substances collect on
the top of the melted metal in the form of a slag, which can be removed
mechanically. If the nickel contains zinc it should be melted in order
to volatilize the zinc and drive it off. The crucible in such case must
not be closed so tightly as to prevent the escape of the zinc fumes. If
copper, arsenic, or antimony is present in the nickel it can be removed
after the nickel is dissolved by passing sulphuretted hydrogen through
the solution. The acid to be used in dissolving the metal consists of
one part strong nitric acid, six parts muriatic acid, and one part water.
Nitric acid or muriatic acid may be used separately, but the above
mixture is preferred. A quantity of this acid is taken sufficient to
dissolve any given amount of the metal with as little excess of the
former as possible; a gentle heat is all that is required. The resulting
solution is then filtered, and to prepare the solution of the double
sulphate of nickel and ammonia a quantity of strong sulphuric acid
sufficient to convert all the metal into sulphate is added, and the solution
is then evaporated to dryness. The mass is then again dissolved in
water and a much smaller quantity than before of sulphuric acid is
added and the whole again evaporated to dryness, the temperature being
raised finally to a point not to exceed 650° Fahrenheit. This tem-
perature is to be sustained until no more vapors of sulphuric acid can

page_text: be detected. The resulting sulphate of nickel is pulverized and
thoroughly mixed with about one-fiftieth (3) of its weight of carbonate
of ammonia and the mass again subjected to a gradually increasing tem-
perature not to exceed 650° Fahrenheit until the carbonate of ammonia
is entirely volatilized. If any iron is present the most of it will be
converted into an insoluble salt, which may be removed by filtration.
The resulting dry and neutral sulphate of nickel is then dissolved in
water by boiling, and if any insoluble residue remains the solution is
filtered. From the weight of the nickel used before solution the amount
of sulphuric acid in the dry sulphate can be calculated. This amount of
sulphuric acid is weighed out diluted with four times its weight of water
and saturated with pure ammonia or carbonate of ammonia, the former.
is preferred. This solution if it is at all alkaline should be evaporated
until it becomes neutral to test paper. The sulphate of ammonia of
commerce may likewise be used, but pure sulphate of ammonia is to
be preferred. The two solutions of the sulphate of nickel and sulphate
of ammonia are then united and diluted with sufficient water to leave
one and a half to two ounces of nickel to each gallon of solution and the
solution is ready for use. The object of twice evaporating to dryness and
raising the temperature to so high a degree is, in the first place, to drive
off the excess of sulphuric acid, and secondly, to convert the sulphate of
iron if it exists into basic sulphate which is quite insoluble in water.
In order to give the best results it is necessary that the solution
should be as nearly neutral as possible, and it should in no case be acid.
The Inventor prefers to use the solution of a specific gravity of about
1052 (water 1000), though a much weaker or a still stronger solution
may be used.
At temperatures above the ordinary the solution still
gives good results, but is liable to be slowly decomposed. An excess of
sulphate of ammonia may be used to dilute the solution in cases when
it is desirable to have it contain much less than an ounce of nickel to
the gallon.
In preparing the solution of the double chloride of nickel and ammo-
nium the nickel is to be purified and dissolved in the same manner as
is described for the previous solution, and it is to be freed from copper
and other foreign matters in the same manner. The solution is then
to be evaporated to dryness; it should be made as nearly anhydrous as
possible. The salt is then placed in a retort and heated to a bright red
heat. The salt sublimes and is collected in a suitable receiver, the

page_text: carthly matter being left behind. The salt thus purified is dissolved
in water, and to the solution is added an equivalent quantity of purc
chloride of ammonium. The solution is then ready for use; it may
have a speciflo gravity of 1050 to 1100. Of these two solutions the
Inventor much prefers the double sulphate, as it gives a softer metal,
which can be polished or otherwise worked more readily than that
obtained from the double chloride solution. The double sulphate
solution has this important advantage over any other solution with
which I am acquainted, that it gives a deposit with a smooth surface,
which can be polished with comparatively little labor. When the
process is properly conducted the deposit can be made much thicker
than is ordinarily required for plating other metals before it acquires
a rough or matted surface. With a metal so hard as nickel this is a
matter of great importance.
Another important part of the Invention is the preparation of the
nickel plates to be used as anodes in the depositing cells. Almost all
commercial nickel contains more or less copper, zinc, and arsenic, and
the complete removal of all these metals would be a matter of great
difficulty and expense, and yet it is necessary to remove them or in some
way counteract or neutralize their influencc. When those metals arc
present they are to some extent deposited with the nickel and seriously
affect the character of the deposited nickel. Copper impairs its color,
and has a tendency to produce a gray hard deposit less tenacious and
coherent than pure nickel, more easily tarnished, and hard to polish.
A very small amount of arsenic makes the nickel tarnish readily in the
air. Zinc affects the deposited metal in much the same way as copper
and it also tends to cause the evolution of hydrogen at the cathode or
negative pole and thus interferes with the deposition of the nickel.
The Inventor has discovered that in his improved solutions the
depositions of copper and arsenic when present with the nickel may
be effectually prevented by combining iron with the nickel. The iron
itself is almost wholly precipitated as a peroxide, and is not deposited
with the nickel to a sufficient extent to injure the character of the
deposit, neither does it injuriously affect the solution. The effect of
the iron upon the copper is either to prevent it from being dissolved, or
if dissolved to immediately reduce it upon the anode, where it forms a
coating which may be removed from time to time by scraping. The
arsenic forms an insoluble precipitate with the persalt of iron. The

page_text: amount of iron which should be combined with the nickel will vary
with the amount of copper and arsenic present and should be as nearly
as possible the chemical equivalent of the amount present of those
metals. It can be combined with the nickel by introducing the proper
quantity in small fragments into the crucible in which the nickel is
melted. Sometimes commercial nickel has sufficient iron present to
counteract the influence of the copper and arsenic. When copper and
zine are present to any considerable extent in nickel it may be melted
in a crucible and cast into plates for anodes without any serious difficulty,
as it then melts at a temperature not much greater than the melting
point of cast iron. The presence of cast iron also facilitates the melting
of nickel. Pure nickel is very hard to melt, but it may be melted without
much difficulty by introducing into the crucible carbon in a finely
divided state, or silica, or both, and the presence of these substances in
the nickel does not injure the solution. It is necessary to melt com-
mercial nickel not only to cast it into plates for anodes and combine it
with iron when copper and arsenic are present, but to remove any potash,
soda, lime, or alumina left adhering to it in the process of reduction,
these substances being removed as before stated as slag. When zinc is
present it will be removed to a great extent in the process of melting
by volatilization unless the melting is done in a tight vessel.
Having prepared the solutions and anodes as herein described nickel
may be readily deposited, but in order to carry on the deposition con-
tinuously it is necessary to observe certain precautions :-
First. The use of a battery of too high an intensity must be avoided,
an intensity of two Smec cells is sufficient. A high intensity decomposes
the solution and liberates free ammonia, thus rendering the solution
alkaline and impairing its value. Whenever the smell of free ammonia
arises from the decomposing cell the operator may be certain that the
solution is being injured. It is important that the depositing shall not
be forced by the use of too strong a current.
Second. It is important that great precaution should be used to prevent
the introduction into the solution of even minute quantities of potash,
soda, or nitric acid. When an article to be coated is cleaned in acid or
alkaline water, or is introduced into it for any purpose, the greatest
care must be taken to remove all traces of these substances before the
article is introduced to the nickel solution, as the introduction of the
most minute quantities of acids or alkalies will surely be injurious.

page_text: It is important that the solution be kept free from all foreign substances,
but its purity from those above named is especially important.
Third. The anode of the depositing cell should present a surface to
the action of the solution somewhat larger than the surface upon which
the deposit is being made, particularly in the double sulphate solution.
The reason is that neckel dissolves so slowly that if the exposed surface
is not larger than the surface on which the deposit is made the solution
will not keep saturated. On the other hand if the anode is very
much larger than the positive pole it tends to give a deposit of black
powder.
Fourth. If zinc is to be coated it should first be coated with copper,
as it is difficult to make nickel adhere to zinc, and there is danger that
the zinc may be acted on and injure the solution. With solutions and
anodes thus prepared and used the deposition of nickel can be carried
on continuously and almost as surely and certainly as the deposition of
copper from the common sulphate solution, though the limits of the
battery power which may be used are narrower. The metal deposited
is compact, cohesive, and tenacious. It may be deposited of nearly
uniform thickness over any surface however large. The deposited metal
is capable of being annealed by a heat below a low red heat; it then
become flexible, malleable, and ductile. The deposit may be made of
any required thickness either to furnish effectual protection to the metal
on which it is deposited or to be removed and used separately from the
surface on which it may be deposited. Thus electrotype plates of
nickel may be produced either as copies of irregular surfaces which
it is desired to reproduce, or as plain sheets of nickel, which after being
annealed may be rolled, hammered, or spun into a variety of forms or
articles.
The solutions also give the full equivalent of nickel for the electricity
employed. The Inventor believes deposits possessing these qualities were
never produced except by means of these his improvements. I therefore
claim,―
First. The clectro-deposition of nickel by means of a solution of the
double sulphate of nickel and ammonia, or a solution of the double
chloride of nickel and ammonium prepared and used in such a manner
as to be free from the presence of potash, soda, alumina, lime, or nitric
acid, or from any acid or alkaline reaction.

page_text: Second. The use for the anode of a depositing cell of nickel com-
bined with iron to prevent the copper and arsenic which may be present
from being deposited with the nickel or from injuring the solution.
Third. The methods herein described for preparing the solution of
the double sulphate of nickel and ammonia, and the double chloride
of nickel and ammonium.
Fourth. The electro-plating of metals with a coating of compact,
coherent, tenaceous, flexible nickel of sufficient thickness to protect the
metal upon which the deposit is made from the action of corrosive
agents with which the article may be brought in contact.
Fifth. The deposition of electrotype plates of nickel to be removed
from the surface on which the deposit is made and used separately
therefrom.
In witness whereof, I, the said William Brookes, have hereunto
set my hand and seal, this Twenty-eighth day of October, in the
year of our Lord One thousand eight hundred and sixty-nine.
WILLIAM BROOKES. (L.S.)