IMPROVEMENTS IN SCREW PROPELLERS
Year: 1859

page_text: LETTERS PATENT to Alexander Prince, of the Office for Patents,
4, Trafalgar Square, Charing Cross, in the County of Middlesex, for
the Invention of "IMPROVEMENTS IN SCREW PROPELLERS."-A commu-
nication from abroad by Hermann Hirsch, of Berlin, in the Kingdom
of Prussia.
Sealed the 22nd November 1859, and dated the 25th May 1859.
PROVISIONAL SPECIFICATION left by the said Alexander Prince at the
Office of the Commissioners of Patents, with his Petition, on the
25th May 1859.
I, ALEXANDER PRINCE, of the Office for Patents, 4, Trafalgar Square,
Charing Cross, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN SCREW PROPELLERS," (a communication
from abroad by Hermann Hirsch, resident at Berlin, in the Kingdom of
Prussia,) to be as follows:-
The special peculiarity of this Invention consists in the co-operation of the
centrifugal force obtained by its peculiar construction, which is as follows:-
Take a plain surface in the form of a square, in this describe a circle (the
outer edges of both touching), having two diameters intersecting each other at
right angles, and a third drawn through the circumference to two opposite
sides of the square in such a direction that the two quadrants are thus divided
into arcs of 60° and 30°. The square surface being divided at the line
through the circumference is then so bent or curved that the half of the same
on the right hand is brought over and down the upper point coinciding with
the lower; the other half being treated in like manner, two hollow cones are
formed, whose bases deviate but slightly from circles, and at the circum-
ference of each the two points are bent outwards. The form of this propeller

page_text: being now determined, it will appear evident that by uniting the two point to
point and side by side, and fixing the points of the cones to the driving shaft,
the cones strike and enter the water alternately, thereby giving the desired
effect of propelling the vessel forward.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Prince in the Great Seal Patent Office on the
25th November 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
PRINCE, of the Office for Patents, 4, Trafalgar Square, Charing Cross, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of May, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Alexander Prince, Her special licence that I, the said
Alexander Prince, my executors, administrators, and assigns, or such others
as I, the said Alexander Prince, my executors, administrators, and assigns,
should at any time agree 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
"IMPROVEMENTS IN SCREW PROPELLERS," a communication from abroad by
Hermann Hirsch, resident at Berlin, in the Kingdom of Prussia, upon the
condition (amongst others) that I, the said Alexander Prince, my executors
or administrators, by an instrument in writing under my, or their, or one of
their hands and seals, 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 Alexander Prince, 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:-
The special peculiarity of this Invention consists in the co-operation of the
centrifugal force obtained by its peculiar construction, which is as follows:-

page_text: Take a plain surface in the form of a square, in this describe a circle (the
outer edges of both touching) having two diameters intersecting each other at
right angles, and a third drawn through the circumference to two opposite
sides of the square in such a direction that the two quadrants are thus divided
into arcs of 60° and 30°. The square surface being divided at the line through
the circumference is then so bent or curved that the half of the same on the
right hand is brought over and down the upper point coinciding with the
lower; the other half being treated in like manner, two hollow cones are
formed, whose bases deviate but slightly from circles, and at the circum-
ference of each the two points are bent outwards. The form of this propeller
being now determined, it will appear evident that by uniting the two point to
point and side by side, and fixing the points of the cones to the driving shaft,
the cones strike and enter the water alternately, thereby giving the desired
effect of propelling the vessel forward.
Having now fully described the nature and object of the said Invention
of "Improvements in Screw Propellers," together with the manner in which
the same is to be performed, I would remark, in conclusion, that I do not
confine myself to the particular inclination of the diameter on which the plane
is folded into a double cone, as above described; but what I claim is, the
mode of forming a propeller consisting of two cones, whose axes are inclined
to one another, and whose points are attached to the axis of the propeller, the
said form being such as can be produced by the folding and bending in
opposite directions of two halves of a plane surface, as above fully described
and set forth.
In witness whereof, I, the said Alexander Prince, have hereunto set my
hand and seal, this Twenty-fifth day of November, in the year of our
Lord One thousand eight hundred and fifty-nine.
ALEX. PRINCE. (L.S.)
Witness,
ALEX. PRINCE, jun.,
Patent Office,
4, Trafalgar Square, Charing Cross.