AN IMPROVEMENT IN THE MANUFACTURE OF TIN FOILS OR SHEETS
Year: 1854

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street, in
the City of London, Patent Agent, for the Invention of "AN IMPROVEMENT
IN THE MANUFACTURE OF TIN FOILS OR SHEETS."-A communication.
PROVISIONAL SPECIFICATION left by the said Richard Archibald Broo-
man at the Office of the Commissioners of Patents, with his Petition,
on the 27th February 1854.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention for
"AN IMPROVEMENT IN THE MANUFACTURE OF TIN FOILS OR SHEETS" to be as
follows:-
This Invention consists of an improvement in the manufacture of tin foils
or sheets, by means of which a material reduction of the cost thereof is effected,
while those qualities which are essential to the purposes for which such foil or
metal is required are retained. This is effected by combining the baser and
cheaper metal, lead, with the tin, not, however, in the form of an alloy or
mixture, but in such manner that each metal will be kept perfectly distinct,
the tin or superior metal only being exposed, while the lead or inferior metal
is encased within it.
In order to manufacture such sheets or foils, a peculiar ingot or slab must be
first made, by which the whole amicunt of the metals to be contained in the

page_text: intended sheet or foil shall be joined at their surfaces, and retained in such
position that the subsequent action of the rolls may not be able to displace or
extend one metal more rapidly than the other; for it is evident that the lead,
by reason of its being the softer and more yielding metal, would be squeezed
out in an undue proportion to the tin, were it not confined on all sides by the
tin. The ingot or slab for rolling is therefore formed in the following
manner First, a metallic mould is made, which determines the size of the
slab to be cast; the cavity in such mould may be, say 6 inches wide, 1 inch
thick, and 10 inches long; a slab of lead is then prepared as much less in size
than the cavity in the mould as is designed for the different proportions of the
metals, say of the following dimensions, 5 inches wide, 9 inches long, and
an inch thick. This, when suspended in the centre of the mould, will leave
a clear space all round, and the tin can then be poured in. To accomplish
the suspension of the lead slab properly in the mould, small blocks or posts of
tin are prepared, of a length equal to the space left between the lead and the
sides of the mould, and by placing these around on all sides, the slab of lead
is sustained exactly in the centre. The surface of the lead being perfectly
clear, or properly fluxed or coated with an alloy of lead and tin, the mould is
ready to receive the tin, which is poured in until the whole of the space
is filled, the lead being then completely encased within it. The posts of tin of
course combine with the fluid tin poured in, and form part of the solid mass.
The slab is now ready for the rolls, and may be extended into sheets and foils
of any degree of thinness.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent Office
on the 26th August 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of February, in the year of our Lord
One thousand eight hundred and fifty-four, in the seventeenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Richard Archibald Brooman, Her special licence, that I, the said Richard
Archibald Brooman, my executors, administrators, and assigns, or such others
as 1, the said Richard Archibald Brooman, my executors, administrators, and

page_text: agree
assigns, should at any time with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVEMENT IN THE MANUFACTURE OF TIN FOILS OR SHEETS," (communicated to
me by a foreigner residing abroad), upon the condition (amongst others) that I,
the said Richard Archibald Brooman, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Richard Archibald Brooman, do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof (that is to say) :-
This Invention consists of an improvement in the manufacture of tin foils or
sheets, by means of which a material reduction of the cost thereof is effected,
while those qualities which are essential to the purposes for which such foil or
metal is required are retained. This is effected by combining the baser and
cheaper metal, lead, with the tin, not, however, in the form of an alloy or
mixture, but in such manner that each metal will be kept perfectly distinct,
the tin or superior metal only being exposed, while the lead or inferior metal
is encased within it.
In order to manufacture such sheets or foils, a peculiar ingot or slab must
be first made, by which the whole amount of the metals to be contained in the
intended sheet or foil shall be joined at their surfaces, and retained in such
position that the subsequent action of the rolls may not be able to displace or
extend one metal more rapidly than the other; for it is evident that the lead,
by reason of its being the softer and more yielding metal, would be squeezed
out in an undue proportion to the tin, were it not confined on all sides by the
tin. The ingot or slab for rolling is therefore formed in the following
manner: First, a metallic mould is made, which determines the size of the
slab to be cast; the cavity in such mould may be, say, six inches wide, one
inch thick, and ten inches long; a slab of lead is then prepared, as much less
in size than the cavity in the mould as is designed for the different proportions
of the metals, say, of the following dimensions, five and a half inches wide, nine
and a half inches long, and half an inch thick; this, when suspended in the
centre of the mould, will leave a clear space all round, and the tin can then be
poured in. To accomplish the suspension of the lead slab properly in the

page_text: mould, small blocks or posts of tin are prepared, of a length equal to the space
left between the lead and the sides of the mould, and by placing these around
on all sides, the slab of lead is sustained exactly in the centre. The surface of
the lead being perfectly clean, or properly fluxed or coated with an alloy of
lead and tin, the mould is ready to receive the tin, which is poured in until the
whole of the space is filled, the lead being then completely encased within it;
the posts of tin of course combine with the fluid tin poured in, and form part
of the solid mass. The slab is now ready for the rolls, and may be extended
into sheets and foils of any degree of thinness. From this formation of the
slab or ingot, it is evident that the lead cannot escape from the tin, but must
extend and be pressed out with it in exactly the same manner and at the same
rate, thus insuring perfect equality in regard to the given proportions first
adopted as to every part of the sheet, no one part having more lead in
combination with it than another. Thus foils or sheets are produced, which
for many of the purposes to which those of pure tin are applied, such as for
wrappers of tobacco, caps for bottles, &c., are fully equal in the qualities
required to those of pure tin, while they are furnished at a greatly reduced
cost.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I do not claim generally
the manufacture of foils or sheets from tin and lead combined in separate
strata, as I am aware that such foils or sheets have been manufactured from
tin and lead caused to unite by pressure between rollers; but what I do
claim is,―
The manufacture of foils or sheets composed of tin and lead in separate
strata combined, so that the exposed or external surface shall be pure tin only,
by the means and in the manner herein-before described.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Twenty-fourth day of August, One
thousand eight hundred and fifty-four.
A
BROOMAN