AN IMPROVED PROPELLER
Year: 1860

page_text: LETTERS PATENT to William Henry Crispin, of Marsh Gate Lane;.
Stratford, in the County of Essex, Copper. Smelter, for the Invention.
of "AN IMPROVED PROPELLER."
Sealed the 12th February 1861, and dated the 18th August 1860.
PROVISIONAL SPECIFICATION left by the said William Henry Crispiu at
the Office of the Commissioners of Patents, with his Petition, on the
18th August 1860.
I, WILLIAM HENRY CRISPIN, of Marsh Gate Lane,. Stratford, in the County,
of Essex, Copper Smelter, do hereby declare the nature of the said Invention
for "AN IMPROVED PROPELLER," to be as follows:-
This propeller consists of two flat discs or blades, the same being mounted;
on a spindle or boss, and intersecting but not touching each other at a suitable
angle to the axial line of such spindle or boss. The discs or blades are of a
form obtained by the intersection of two circles, the lateral diameter being
greater than the vertical diameter, and the sharpness of the points of inter-.
section being removed or rounded off. The discs or blades are not mounted on;

page_text: the exterior of the spindle or boss, but the latter passes through each disc or
blade at the inner side of its smaller diameter. The boss may be made of a
spherical form, the relative angle of the discs or blades to the axial line thereof
being preserved. The propeller is attached to a shaft driven by machinery in
the ordinary way, and works entirely submerged.
SPECIFICATION in pursuance of the conditions of the Letters-Patent, filed
by the said William Henry Crispin in the Great Seal Patent Office on
the 15th February 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENRY CRISPIN, of Marsh Gate Lane, Stratford, in the County of Essex,
Copper Smelter, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent,-bearing-date-the-Eighteenth-day of August, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Henry Crispin, Her special licence that I, tlie said William
Henry Crispin, my executors, administrators, and assigns, or such other's as I,
the said William Henry. Crispin, 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 "AN IMPROVED PROPELLER," upon the condition (amongst others) that I,
the said William Henry Crispin, my executors or administrators, by an instru-
ment 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 William Henry Crispin, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed; to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed (that is to
say):

page_text: The propeller, which is the subject of my Invention, consists of two flat discs
or blades mounted on a spindle or boss, and intersecting but not touching each
other at any desired angle to the axial line of such spindle or boss. The discs
or blades, which are of a form obtained by the intersection of two circles, the
lateral diameter being greater than the vertical diameter, are not mounted on
the exterior of the boss or spindle, but the latter passes through each disc or
blade at the inner side of its smaller diameter, each disc or blade performing
its revolutions eccentrically around the axial line of the boss or spindle.
The discs or blades are perfectly flat, and may be made of, iron, steel, copper,
or any suitable metal or metallic alloy, the material of which they may be
formed being no part of my Invention. It should be observed that the discs
or blades of my propeller do not constitute any portion of a screw. The acute
angles formed by the lines of intersection may, if desired, be reduced or
rounded off, and the edges of the discs or blades may be made sufficiently thin
and sharp to cut or divide any seaweed, cordage, or other floating substances
with which the propeller might otherwise in its revolution become clogged. It
should be observed, however, that one important advantage connected with my
Invention is, that when revolving, the action of the propeller is such as to repel
any substances which may be floating in its vicinity. This result is owing to
the position and relative pitch of the discs or blades. I should also remark,
that from the form of the propeller and from its working entirely submerged,
it will be less liable, when applied to ships of war, to injury from shot than
the propellers in ordinary use.
Another advantage resulting from the method of construction above described
is, that propellers so constructed will be much lighter than those which are
now ordinarily employed, while they will at the same time be much more
economical in their original cost, and will possess great durability.
With regard to the boss, I do not limit myself to the use of any particular form,
but employ either a spherical boss or a cylindrical shaft or spindle; in either
case the propeller being connected by means of the boss or spindle with a
shaft driven by any machinery adapted for the purpose in the ordinary way.
Figures 1 and 2 in the annexed Drawings represent the propeller as con-
structed with a spherical boss, and Figures 3 and 4 with a cylindrical boss or
spindle, the rounding off of the acute angles before referred to being shewn in
each case by dotted lines.
Having thus described my said Invention, and the manner in which it is to
be performed, I would observe in conclusion, that what I consider to be novel,

page_text: and original and therefore claim as my Invention is, a propeller of the form
and constructed in the manner herein-before mentioned and described.
In witness whereof, I, the said William Henry Crispin, have hereunto
hand and seal, this Fourteenth day of February, in the year of
our Lord One thousand eight hundred and sixty-one.
set my
Witness,
E. P. H. VAUGHAN,
15, Southampton Buildings,
WM. H. CRISPIN. (L.S.)
Agent for the Patentee.