Coining is the term applied to the processes employed in the
manufacture of money. It is proposed to describe the present mode of
manufacture; but it may be as well to state, that in remote periods
money was made by cutting out a piece of metal somewhat of the form
of the intended coin, and imparting the device to it by the blow of a
sledge-hammer. For this purpose the blank piece of metal was laid upon
a die, say the obverse, fixed into a block of wood or stone, supposed
to have been so large as to absorb the vibration caused by the blow,
and to a great extent prevent the quivering which would naturally
arise, and cause unsteadiness. The workman then took the other die, say
the reverse, and passing it through a folded sheet of lead, in order to
avoid the shock to the hand, he placed the engraved part on the blank,
which was resting on the lower die, and held it firmly while another
workman struck it with a sledge-hammer. It is worthy of remark that a
piece of lead such as that described is in the Museum of Dies at the
Royal Mint; and although its surface, by the action of the atmosphere
and other causes, is now converted into carbonate of lead, indentations
caused by the tips of the workman’s fingers are evident. This piece is
believed to have been used with a die of Edward IV. At a later period
the upper die was held in a twisted hazel stick. After each blow the
dies were what is technically termed locked together; that is, the
lower and upper dies were made to fit into the partly-formed coin, so
that neither die could turn without turning the whole mass, and then
a second or third blow was given, till the coin was completed. An
improvement on this method was effected by fitting the two dies into
rods of iron, which may be represented as a pair of tongs; the flat
parts which are used to take a coal would then be the position occupied
by the dies. This plan saved the operator some risk of bruised fingers,
but the process was essentially the same as the original one; and to
money produced by either means was applied the term _hammered_ money,
in contradistinction to _milled_ money; that is, money which was made
from blanks obtained from fillets which had been rolled in a very rough
kind of rolling mill, driven by horse power—the germ from which sprang
the present machinery. On this point it is perhaps of interest to quote
a passage from the Report made to the Lords of the Treasury in 1695 by
Mr. William Lowndes, who says:—“All the moneys we have now in England,
both gold and silver, are reducible to two sorts, one stamped with the
hammer, and the other pressed with an engine called the mill. The gold
or silver of the hammered money is first cast from the melting-pot into
long bars, those bars are cut with shears into several square pieces of
exact weight for sovereigns, angels, crowns, half-crowns, shillings,
&c. Then with tongs and hammer they are forged into a round shape,
after which they are blanched (that is, made white or refulgent by
nealing or boiling), and afterwards stampt or impressed with an hammer
to make them perfect money. This method of making money with the hammer
(as appears in the said red book) was practised in the reign of King
Edward the first” [the book referred to is in the Exchequer] “and this
kind of hammered money continued through all the reigns of succeeding
Kings and Queens till about the year of our Lord 1663, when by several
warrants and command of the King, Charles the Second: to wit, by one
warrant, dated the fifth of November, 1662; one warrant, dated the
eighth of April, 1663; and a third warrant, dated the twenty-fourth
of December, 1663; the other sort, called _milled money_, was first
fabricated to be current in England in this manner: first, the gold or
silver is cast out of the melting-pot into long flat bars, which bars
are drawn through a mill (wrought by a horse), to produce the just
thickness of guineas, half-guineas, crowns, half-crowns, shillings,
&c. Then with forcible engines called _cutters_, which answer exactly
to the respective sizes or dimensions of the money to be made, the
round pieces are cut out from the flat bar, shaped as aforesaid (the
residue whereof, called sizel, is melted again), and then every piece
is weighed and made to agree exactly with the intended weight, and
afterwards carried to other engines (wrought secretly), which put the
letters upon the edges of the larger silver pieces, and mark the edges
of the rest with a graining. The next thing is the blanching, performed
as above; and at last every piece is brought to the press, which is
called the _mill_ (wrought of the strength of men), and there receives
the impression, which makes it perfect _milled_ money.”
The processes now used are as elaborate as the old methods were simple;
but considering the requirements of the present day, and the enormous
quantity of money produced, it must not be expected that our coins
will, for depth of engraving, bear comparison with those of the Romans,
who, though succeeding in producing finished works of art, seem to have
forgotten the wear and tear to which they would be subjected, and so
left them, as a rule, free from a protecting edge; hence they would
lose their image and superscription at a far earlier date from their
birth or manufacture than would well-made coins of the present period.
It was formerly believed that gold could be sent to the Mint to be
coined free of charge to the importer; such, however, was not the case.
By the Act 33 Victoria, cap. 10, several Acts relating to the coinage
are repealed, and all persons[7] obtain the right to send gold to the
Mint to be coined on the following terms:—
“8. Where any person brings to the Mint any gold bullion,
such bullion shall be assayed and coined, and delivered
out to such person, without any charges for such assay or
coining, or for waste in coinage. Provided that (1)—If
the fineness of the whole of the bullion so brought to the
Mint is such that it cannot be brought to the standard
fineness under this Act of the coin to be coined thereout
without refining some portion of it, the Master of the Mint
may refuse to receive, assay, or coin such bullion. (2)
Where the bullion so brought to the Mint is finer than the
standard fineness under this Act of the coin to be coined
thereout, there shall be delivered to the person bringing
the same such additional amount of coin as is proportionate
to such superior fineness. No undue preference shall be
shown to any person under this section, and every person
shall have priority according to the time at which he
brought such bullion to the Mint.”
The standard for gold is fixed by the new Act at “Twenty-two carats
fine and two carats of alloy in the pound weight troy”—the same that
was specified in the 3rd Edward VI., 35th Elizabeth, 2nd Charles I.,
and 18th Charles II. Silver is maintained at the former standard of
“Eleven ounces two pennyweights fine silver and eighteen pennyweights
of alloy in every pound weight troy.” Until the passing of this Act
silver was coined under that of George III., which repealed the Act 18
Charles II., as regards the coining of silver free of charge. The Act
33 Victoria, cap. 10, repeals that of George III., but fails to make
provision for the coining of silver, which is therefore now coined
under the Common Law; yet the new Act specifies the weight and fineness
of the silver coinage. The omission was made because the Chancellor
of the Exchequer thought it “unfair to introduce silver to this Act
as it is a source of revenue;” a little later I will examine this
statement.[8]
The Bank of England is practically the only “importer” of bullion to
the Mint, and by coinage makes a considerable profit merely from its
exceptional circumstances. By its charter and by Act of Parliament
it is compelled to keep a stock of bullion equivalent to the excess
of its authorised issue of notes—such authorised issue being secured
by “Government debt” and “other securities”—which at the present
time is fifteen millions; and gold, when at the Mint for coining, is
esteemed as being still at the Bank. By the Act 7 and 8 Victoria, cap.
32, section 4, the Bank of England is compelled to purchase bullion,
previously melted and assayed at the cost of the seller, at the rate
of £3 17_s._ 9_d._ per ounce of standard gold, paying for it in Bank
of England notes. Assuming that all the gold thus purchased is coined,
the Bank makes a profit[9] of about £2,000 on each million. When its
authorities desire to coin gold they give notice at the Mint, and
subsequently send at stated intervals “importations” of say 200 ingots
of gold, each weighing about 180 ounces, and previously assayed. Upon
the arrival of these ingots at the Mint, they are taken to an office,
where, in the presence of an officer from the Bank of England, a
small piece is cut from each ingot, and hammered out into a kind of
strip. This piece is then put into a paper marked with a letter which
corresponds with the mark or letter on the individual ingot from which
it was taken. This having been effected for each ingot, the pieces are
forwarded with their respective ingots to the Mint Office, where their
weight is determined and compared with that charged by the Bank of
England. The pieces which have been hammered out and placed in a marked
packet are called the “assay pieces.” The assay pieces are sent to the
resident assayer in the Mint, who estimates and reports to the Master
the amount of pure gold in each ingot. The report of the resident
assayer is then submitted to the Bank authorities, and if they find it
to agree with their own assayer’s report, the ingots are retained for
operations in the Mint. When it is desired to get the ingots of gold
into a form fit for coining, they have to be alloyed with copper, or
fine gold must be added, so as to bring them to standard or crown gold,
which consists of 22 parts of pure gold and 2 parts of alloy, or 91·66
per cent. of gold and 8·33 per cent. of copper in 100 parts. Copper is
usually employed because it is cheaper, and forms a harder alloy than
silver.
[Footnote 7: See page 169.]
[Footnote 8: See pages 126, 144-156.]
[Footnote 9: See pages 126-127, 168.]
Supposing there are 100 ingots, having a total weight of 18,000 oz.,
and by assay it has been found that they contain 17,900 oz. of pure
gold, it is required to bring them to the standard fixed by law. A
rule-of-three sum tells how much alloy or how much gold is to be added.
So, if 22 parts of pure gold require 2 parts of alloy, how much alloy
will 17,900 parts require? The fourth term of the following proportion,
viz., as 22:2::17,900:1,627·027, will show how much is to be added; but
since there are already 100 oz. of alloy present, as indicated by the
fact that 18,000 oz. contain within themselves only 17,900 oz. of pure
gold, it is only necessary to add the excess required, viz., 1,527·027,
so that these 100 ingots will produce 19,527·027 oz. of standard gold.
Had the ingots been found to contain more alloy than is required,
it would have been necessary to add so much pure gold as would have
rendered the whole standard. The proportions of the metals having been
determined, the whole mass is divided so as to make about 1,200 oz.
of gold and alloy for each melting-pot. In practice it is customary
to take the estimated amount of gold in a given number of ingots, and
add so much alloy, or so much pure gold, as shall bring those ingots
to standard, the whole weight being generally about 1,200 oz.; this is
called _potting_ the ingots. Ingots are almost invariably melted, and
cast into bars for sovereigns.
I must here mention that the various illustrations I have introduced
were originally used for the article “COINING” in TOMLINSON’S
“CYCLOPÆDIA,” and the permission to use them here has been generously
granted to me by _Messrs. Virtue and Co._, whose property they are.
In the illustrative engravings, the initial letters used to indicate
the different parts are made to take their places in accordance with
the order in which the various parts of the machine under description
come into play, so that by tracing out the alphabet in any figure, the
reader will see the consecutive action of the parts of the machine he
is studying.
[Illustration: Fig. 1.—Gold Melting.]
Fig. 1 represents the arrangements for melting the ingots with their
alloy, for producing standard gold. In the Mint there are seven
furnaces: each furnace, A, is 12 inches square and 24 inches deep to
the top of the bars, which are seen at the ash-pit B. The pot C is
made of a mixture of Stourbridge clay and plumbago, hence called a
_plumbago pot_; it is 9¼ inches deep, and 7 inches across at the top
inside. The pot, previously annealed, is placed in the furnace on a
_bottom_ which stands upon the two centre bars. The bottom is intended
to shelter the base of the pot C from the stream of air which is
necessary to the combustion of the fuel, but which would damage the
pot. The pot is then covered by its muffle and lid, and surrounded by
fuel, which, as it burns up, warms and then heats the pot to redness,
but so gradually that there is no great risk of breaking the pot. When
the pot has become of a full red heat, the ingots are carefully placed
in it, and the alloy is added by means of the funnel I: the pot is
then covered up, and allowed to remain till the whole mass of metal
has liquefied. The foreman then stirs it with a rod made of the same
substance as the pot, and allows it to remain till the fluid mass has
reached a peculiar temperature, known by experience as that at which
the metal, when poured into a mould, forms the most solid and workable
bar. This temperature having been gained, the two outside bars at B
are removed, the ash-pit is then covered to protect the men’s feet,
and the firing poked out. The lid and muffle are next removed from
the pot, and the pot lifted by an assistant from the furnace by the
crane D. The foreman then conveys the pot C, by means of a pair of
tongs which clasp it, to the frame of moulds, when an assistant brings
forward a loop of iron, suspended by a chain and cord from the roof
of the building, and passing the loop of iron over a button on the
end of the lower clamp of the tongs, as shown at E, F, supports the
weight of the pot by the cord, as indicated at G. Previously to the
melting, pieces of charcoal are placed at the bottom of the pot for
the purpose of reducing any oxide that may be present in the alloy—and
Dr. Percy has found that copper can dissolve 13·50 per cent. of oxide
of copper—because oxide of copper, when dissolved in standard gold,
frequently renders the mass so brittle that when the bars produced are
passed between the rollers they crack and break, just as does gold
containing minute quantities of lead or zinc. The influence of oxide
of copper on standard gold was thus very marked in 1859, when a large
proportion of the gold was so brittle, that if a bar were dropped on
the floor, or tapped with a hammer, it broke, just as heated brass
breaks under similar circumstances. Mr. Richard Smith had some years
since pointed out that if copper in which oxide of copper is dissolved
be poured through an atmosphere of coal gas, all the oxide is reduced.
I therefore submitted this gold to the process thus suggested to reduce
all the oxide of copper, and produced bars so tough that they could
not be broken by a sledge hammer unless after repeated bending by that
means. Yet this gold was not thus cured of its brittleness, but was
treated peculiarly, as will be seen in a future place.[10]
[Footnote 10: See pages 50-53.]
When the metal is fused, the charcoal which was placed at the bottom
is brought to the surface by stirring, and as it rises through the
fluid alloy, reduces the oxide of copper, and remains on the surface to
protect the alloy from the action of atmospheric oxygen. In order to
prevent it from falling into the moulds, the assistant holds a piece
of stick at the mouth of the pot, thus allowing the gold to pass, but
stopping the charcoal. The foreman, in the case of gold, judges almost
wholly by the eye, but in the case of silver by the ear, as to when
the moulds are filled. The metal poured from each pot forms four bars.
The moulds H are made of iron, cast into such a form that each piece
viewed from the top has the form of the letter =T=, so that three
pieces placed together form two moulds; the whole of the set is held in
its position by cross-bars, L, which fit into notches cut in the main
frame M, where will be seen two powerful screws by which the moulds are
forced tightly together after the cross-bars L are fixed. J represents
the pots placed so as to be kept dry and ready for use; K, the wheels
and tram on which the frame of moulds runs. The whole of the set of
moulds having been filled, the screws at M are loosened, the bars, L,
removed, and the parts of the several moulds removed, so that the bar
in each mould is exposed to view. The workman takes each bar as it is
exposed by a pair of tongs, and plunges it into a cistern of cold water
to insure rapid cooling, and then places it on a bench, where the
bars produced from each pot are separated and marked with a number, to
indicate the pot from which they were poured, and the entire set with
letters, to indicate the day on which the melting took place. After
these distinctive marks have been placed on the bars, two assay pieces
are taken from the bars from each pot.
[Illustration: Fig. 2.—Silver Melting.]
As silver melting,[11] when discreetly conducted, is slightly different
in some of its details, it will be well to describe it here. In Fig. 2,
A indicates the furnace with the front removed, to exhibit the internal
arrangements. The furnace is circular, and is 21·5 inches across, and
31 inches deep. The bars, which are represented by dotted lines, are
removable at will. The _bottom_ B stands on the centre bars, just
as in the case of gold melting: it is filled with coke dust, which
retains any silver issuing from a small accidental crack or pin-hole
in the pot, and also offers a non-conducting medium for the pot C to
rest upon, it being necessary to avoid the abstraction of heat by the
current of air against the base of the pot. A muffle, D, is placed on
the pot, and upon this muffle the lid E rests. The pot is circular,
and provided with a lip, to facilitate the pouring of the metal; it
is made of wrought-iron, 12 inches across at the top, and 15 inches
deep, and when melting for florins is charged with 4,800 ounces of
silver. As in the case of gold, so with silver, the metal is alloyed
with copper; standard silver being composed of 222 parts of pure silver
and 18 parts of copper in 240 parts, or 92·50 parts of silver and 7·50
of copper in 100 parts.[12] The calculations based on the assays from
ingots are just the same as in the case of gold. The ingots are put
into the pot, and the lid is placed on the muffle (which is intended to
prevent metal from falling over the top of the pot during the process
of fusion, as sometimes might happen when _scissel_[13] is melted),
and the furnace is then closed, so that the air enters through the
bars, and passes into the chimney through the flue F. The lid of the
furnace G is provided with peep-holes, by which the temperature can
be regulated at will, while they also admit of a survey of the state
of the furnace. When the fusion is complete, and carried so far as
to raise the fluid metal to the necessary temperature, the bars of
the furnace, with the exception of those which support the pot, are
removed, and the fuel is poked out, because the pot at this temperature
is so soft that it would be _torn_ if it were pulled through the fuel.
The lid and muffle are next taken off by tongs, and the crane is swung
round by the handle, H, till its tongs are brought over the furnace,
when, by working the handle I, the tongs J are lowered till they come
to the pot; the foreman then makes them seize the pot, and by a signal
gives his order for the raising of the pot from the furnace. Pieces
of fuel and iron scaling are knocked off from the pot by the foreman
with a brush kept in a crucible of water, indicated by V at the foot
of the crane. The crane is then swung round by H, till the pot is over
the cradle K, when it is lowered and secured in the cradle by the
screw, shown at C. The frame of moulds is now run under the lip of the
pot, and the foreman, by means of the handle L, which will be seen to
communicate with the wheels M, and the rack N, tilts the pot so that
the fluid metal may pour in a good stream into one of the moulds O,
until, by the sound, he judges it to be full; he then lowers the pot,
while his assistant, who is also watching the filling of the moulds,
turns the handle P, which, by the wheel Q fitting into the rack R,
moves forward the frame of moulds so far as to allow another mould to
come beneath the lip of the pot, to be filled as before. The fluid
silver in the melting-pot is covered with charcoal, for the same reason
as explained in gold melting, and this is kept back by means of a large
piece of charcoal laid at the mouth of the melting-pot. The frame of
moulds runs on wheels S, and at T is provided with a rack and pinion,
by which the moulds may be moved farther from or nearer to the lip of
the pot, which, as it is tilted, is continually altering its relative
position to the mouth of the moulds, and would, were it not for this
arrangement, pour its metal outside of, or upon the moulds, instead
of into them. The moulds are formed of =T= pieces, in the same manner
as the moulds for gold, and are secured in their position by the same
method, the cross-bars being shown at U. The bars, having been taken
from the moulds, are cooled in water, and distinctively marked, as in
the case of gold. Assay pieces are cut from them, but in the case of
silver three assays are taken from the bars produced from each pot.
[Footnote 11: See pages 129-138.]
[Footnote 12: See pages 3, 73.]
[Footnote 13: This word is explained at page 35.]
The bars for different denominations of coins are proportioned in their
width, so as to admit of two rows of blanks being cut from the fillets
produced from them. The following statement gives the whole facts
concerning bars for each coin, as used in the Royal Mint. It would be
well to produce bars of a uniform thickness of 0·50 inch, as such bars
may be cast solid, and when cast produce better fillets with half the
rolling, without the cost of annealing. There would be also another
advantage, for the blanks obtained from the fillets produced from bars
0·50 inch thick would not require annealing, and would thus save the
cost of that process, as well as the loss occasioned by it, while the
coins produced would wear immeasurably longer in circulation. There are
other considerations why this thickness should be at once adopted, as
will be shown when the subject of loss by coining is explained.
I am glad to notice that Mr. Fremantle, in his Report on European
Mints, proposes to adopt my recommendation, as shown by the following
passage, page 9:—
“... It would seem to be a question whether in a newly
organised Mint considerable time and labour might not be
saved by reducing the size of the moulds in which both gold
and silver bars are cast. The result would be that, as
bars would be thinner when first subjected to the process
of rolling, the time now occupied by that process would
be sensibly diminished. It should also be mentioned that
although there is great difficulty in producing sound
castings if the thickness of the bars should be reduced, it
might nevertheless, for the metallurgical reasons which Mr.
Roberts points out, be advisable to make this alteration.”
There is really no “_difficulty_ in producing sound castings if the
thickness should be reduced;” but I fear there are many DIFFICULTIES
in the Royal Mint itself. Indeed the casting of the bronze bars—whose
thickness is less than that I propose for those of gold—gives evidence
of the ease with which thinner bars may be produced; yet against
_these, insuperable difficulties_ were urged until I experimentally
demonstrated how easily they could be cast.