IMPROVEMENTS IN IRON STEAM BOATS
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
NAPIER, of Millwall, in the County of Middlesex, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-third day of April, in the second year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
David Napier, Her especial licence, full power, sole privilege and authority,
that I, the said David Napier, my exors, adññors, and assigns, or such others
as I, the said David Napier, my exors, adñiors, 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 expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "IMPROVEMENTS IN IRON STEAM BOATS;" in which said
Letters Patent is contained a proviso that I, the said David Napier, shall
cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, to be enrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
David Napier, do hereby declare the nature of my improvements, and the
manner in which the same are to be performed, are particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawing hereunto annexed, and to the figures and letters marked
thereon (that is to say) :-
My Invention consists in constructing iron steam boats with double bottoms;

page_text: also in applying the space between the bottoms for the purpose of condensing
the steam from the engines without injection water.
The Drawing represents a transverse section of an iron steamer on the
above construction. A, the space between the two bottoms B and C, which,
when used as a condenser, requires another water-tight iron floor D, about an
inch and a half above C. Into this inch and a half space there are openings
in the bow and stern to allow the water to pass through, for the purpose of
keeping C always cold. a, a, a, are plates of iron like keelsons, rivetted to B
and C, for the double purpose of resisting the pressure and strengthening the
vessel.
I do not mean to confine my Invention to this particular form or con-
struction; it consists in constructing iron steam boats with two water-tight
bottoms, of whatever shape or construction; also in applying the space
between the bottoms for the purpose of condensing the steam from the
engines.
The advantages to be derived from this mode of constructing iron steam
boats are, greater strength and safety, a saving of power in working the air
pump, and a saving in the wear and tear of the boilers, fresh water being
always used, and the quantity remaining nearly always the same, accidents
arising from want of water in the boilers can scarcely ever occur.
In steamers of magnitude I would recommend the doubling to be continued
up the sides.
In witness whereof, I, the said David Napier, have hereunto set my
hand and seal, this Seventh day of October, in the year of our Lord
One thousand eight hundred and thirty-nine