IMPROVEMENTS IN THE MANUFACTURE OF IRON FOR SHIP BUILDING
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
ROBERT MGAVIN, of Glasgow, in the County of Lanark. North
Britain, Merchant, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria,
by Her Royal Letters Patent under the Great Seal of the United
Kingdom of Great Britain and Ireland, bearing date at Westminster,
the Twenty-third day of October, in the sixteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Robert McGavin, Her especial licence, full power, sole privilege
and authority, that I, the said Robert M'Gavin, my exors, admors, and
assigns, and such others as I, the said Robert McGavin, my exōrs,
admörs, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein ex-
pressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick upon Tweed, my
Invention of IMPROVEMENTS IN THE MANUFACTURE OF IRON FOR SHIP
BUILDING," in which said Letters Patent is contained a proviso requiring
that 1, the said Robert McGavin, by an instrument in writing under
my hand and seal, shall particularly describe and ascertain the nature
of my said Invention, and in what manner the same is to be per-

page_text: formed, and shall cause the same to be enrolled in Her said Majesty's
High Court of Chancery within six calendar months next and imme-
diately after the date of the said in part recited Letters Patent.
.
NOW KNOW YE, that in compliance with the said proviso, I, the
said Robert McGavin, do hereby declare the nature of my Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by this present instrument in writing,
as follows:
My said Invention has for its object tlie prevention of the adliesion
of barnacles and other animal matters or formations to the bottoms and
exposed surfaces of iron ships when afloat, or in contact with sea
water. I accomplish this end by adding to or mixing in the iron
of which the ships are to be built a small proportion of. arsenic. This
admixture may be effected either when the iron is, in a stato of fusion,
or at any other suitable and convenient stage in the manufacture or
treatment of the metal, such as in the puddling or blooming processes,
when the metal is soft and plastic. The effect of such admixture
with or treatment of the iron is, that the resultant gradual feeble
solution of the poisonous matter in the water destroys or prevents the
adhesion of all barnacles and marine animal-productions of every
kind, and thus no hold is afforded for the foreign matters which
ordinarily cling to the fundamental animal formations. By adding
the poisonous matter to 'the mass of metal during the process. of
the manufacture of such metal, the latter becomes thoroughly in
corporated with the poisonous ingredient, so that the whole of the
exposed iron of which a ship is built retains its poisonous qualities
until actually worn out, instead of losing such qualities by surface
I may remark that, in practice, I have found it necessary to
add as much of the ordinary white or yellow arsenic of commerce as
the iron will fairly receive without suffering. any deterioration in its
quality. This necessary amount of arsenic, I find, varies from two to
five per cent. of the iron, accordingly as the quality of the latter varies;
and I prefer to effect the admixture of the poisonous matter in the
puddling furnace, the addition being made just before the metal begins
to boil. Or, instead of this routine, the poisonous matter may be placed
wear.

page_text: ensues.
lietween the metal blocks before the latter are heated for the rolling
process. By pursuing this last plan little or no loss of the arsenic
I also find it necessary to sprinkle the outside plate whilst
it is red hot with a little arsenic in addition, this sprinkling to be
performed before completing the rolling; as, for example, before the
last two entrances to the rollers. The poisoned plates are then well
cleaned with strong acid, and are scrubbed with holy stone, and im-
mersed in a mixture of arsenic and spelter, tin, lead, or zinc. It will
be obvious to the practical man that this system of treatment is appli-
cable to the metal employed in various details concerned in naval con-
struction.
Having now described and particularly ascertained the nature of
my said Invention, and the manner in which the same is or may
be used or carried into effect, I may observe, in conclusion, that I
do not confine or restrict myself to the precise details or arrangements
which I have had occasion to describe or refer to, as many variations
may be made therefrom without deviating from the principles or main
features of my Invention. But what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent, is,―
First, the application and use of arsenic in the treatment or manu-
facture of iron for ship building.
Second, the system or mode of preventing the adhesion of animal
matter to iron surfaces by incorporating arsenic in such iron.
In witness whereof, I, the said Robert McGavin, have hereunto
set my hand and seal, this Twenty-second day of April, in the
year of our Lord One thousand eight hundred and fifty-three.
ROBERT
(L.S.) MSGAVIN.
Signed, sealed, and delivered in the presence of
THOMAS PAUL, Clerk to W. & J. H. Johnson.
JAMES RULE, Clerk to D. Paul.
AND BE IT REMEMBERED, that, on the Twenty-second day of
AND BE IT REMEMBERED, that, on the Twenty-second day of
April, in the year of our Lord 1853, the aforesaid Robert McGavin
came before our said Lady the Queen, in Her Chancery, and acknow-

page_text: ledged the Specification aforesaid, and all and every thing therein
contained and specified in form above written; and also the Specification
aforesaid was stamped according to the tenor of the statute made
for that purpose.