AN IMPROVED METALLIC SHEATHING FOR THE BOTTOMS OF SHIPS AND VESSELS
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JACOB
TILTON SLADE, of Carburton Street, Fitzroy Square, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS His Majesty King William the Fourth, by His Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Twenty-fifth day of November,
now last past, did give and grant unto me, the said Jacob Tilton Slade, His
especial licence, full power, sole privilege and authority, that I, the said Jacob
Tilton Slade, my executors, administrators, and assigns, or such others as I,
the said Jacob Tilton Slade, my executors, administrators, or assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "AN IMPROVED METALLIC SHEATHING
FOR THE BOTTOMS OF SHIPS AND VESSELS;" in which said Letters Patent there is
contained a proviso obliging me, the said Jacob Tilton Slade, by an instrument
in writing under my hand and seal, particularly to describe and ascertain the
nature of my said Invention, and in what manner the same is to be per-
formed, and to cause the same to be enrolled in His Majesty's High Court

page_text: of Chancery within six calendar months next and immediately after the date
of the said recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Jacob Tilton Slade, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, is described and
ascertained by the following description thereof (that is to say):-
I take a plate or sheet of sheathing copper, tinned on one side in the usual
manner, and cover it on that side which is not tinned with a thick paste com-
posed of a mixture of pipeclay and wheat flour, in equal parts by weight,
boiled up with the proper quantity of water. When the paste thus applied to
the surface of the copper has become dry, I dip the plate or sheet into a cast
iron or other convenient vessel nearly filled with a mixture of tin and lead in
a state of fusion. The proportion of these two ingredients cannot be precisely
pointed out, as it depends on the purity of the tin and of the lead. The
ordinary block or bar tin will bear an equal part of lead, and the purer the tin
is the greater proportion of lead may mixed with it. The general rule that I
follow is to employ as small a proportion of tin as possible, consistent with
obtaining a strong and sound adhesion of the lead to the surface of the copper.
The time that the plate is to be kept in the melted metal depends on its
temperature, but in general less than a minute is sufficient to obtain a perfect
coating of the alloy. I then withdraw it, and (if necessary) renew the coat-
ing of the paste at the back of the plate, when it is ready for the third and
finishing process. For this purpose I procure two flat plates of cast iron,
about half an inch longer and wider than the plate of tinned copper above
mentioned. The lower margin of the upper plate has a fillet surrounding it,
the bottom of which is ground quite even, and the depth of the fillet is equal
to the thickness of the lead lacking intended to be applied by means of
this apparatus to the plate of tinned copper. Near one end of this upper cast-
iron plate are made two holes, about a quarter of an inch in diameter, for the
admission of the melted metal; each hole opens above into a cap, and the cap
is pierced transversely by a hole of the same diameter as the former. Into
this transverse hole a stopper of iron is fitted by grinding, while its stem,
passing through two rings or guides, projects a little beyond the opposite side
of the cast-iron plate. The lower cast-iron plate is quite plain and even.
On this lower cast-iron plate I lay the plate of tinned copper, the tinned
surface being uppermost; I then cover it with the upper cast-iron plate,
taking care that the fillet above mention shall stand upon the margin
of the tinned plate all round. I secure the three plates from moving

page_text: on each other by means of screw clamps, and then insert between the
tinned copper plate and the upper cast-iron plate two, three, or more
slips of steel, the thickness of which is such as just to allow them to
enter the space between the plates. These use of these slips of steel is to
prevent any part of the tinned plate from rising. The whole apparatus
being ready, as above described, and the holes in the upper plate being opened
by withdrawing the stoppers, it is introduced obliquely into a cast-iron boiler
filled with melted lead, that end of the apparatus in which are the holes
being the lowest; the melted lead immediately runs through these holes into
the space between the plates, and will have completely filled it by the time
that the upper part of the apparatus shall have reached the surface of the
melted lead. At this time the slips of steel are to be withdrawn; the
handles of the stoppers are to be pushed down so as to close the holes, and
thus prevent the lead that has entered through them from running out again.
The apparatus is to be raised out of the boiler, and when it is grown cold is
to be taken to pieces, when the plate of tinned copper will be found firmly
united to a plate of lead of the thickness of the space between the upper
iron plate of tinned copper. The paste which has been applied on the under
surface of the copper plate is to be removed by soaking it in water and rubbing
it with a hard brush or any other convenient way. The compound plate
obtained, as above described, is my improved metallic sheathing.
In witness whereof, I, the said Jacob Tilton Slade, have hereunto set
my hand and seal, this Twenty-third day of May, in the year of our
Lord One thousand eight hundred and thirty-five.
Inrolled the same Twenty-third day of May, in the year above written.