AN IMPROVED MODE OF AND MEANS FOR PRODUCING OPTICAL ILLUSIONS
Year: 1867

page_text: LETTERS PATENT to Henry Watson Hallett, of Springfield, Massachusetts,
United States of America, now of No. 8, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for the Invention of "AN
IMPROVED MODE OF AND MEANS FOR PRODUCING OPTICAL ILLUSIONS."-A
communication from abroad by Milton Bradley, of Springfield, Massa-
chusetts, United States of America.
PROVISIONAL SPECIFICATION left by the said Henry Watson Hallett
at the Office of the Commissioners of Patents, with his Petition, on the
. 6th March 1867.
I, HENRY WATSON HALLETT, of Springfield, Massachusetts, United States of
America, now of No. 8, Southampton Buildings, Chancery Lane, in the
County of Middlesex, do hereby declare the nature of the said Invention for.
"AN IMPROVED MODE OF AND MEANS FOR PRODUCING OPTICAL ILLUSIONS," to
be as follows:-
The nature of the said Invention consists chiefly, first, in the employment
of a revolving cylinder or drum with slots or apertures in its circumference for
the purpose of exhibiting figures or designs placed around the interior
circumference; and, second, in forming the figures or designs nearly in a line
upon a straight strip of paper or other material, said figures being so formed
and arranged in relation to each other that when the cylinder is revolved they
will present, viewed through the slots, the appearance of moving or life-like
figures. The cylinder is constructed of any suitable size and material, and is
mounted upon a stand, on which it is made to freely revolve. The cylinder is
[Price 8d.1

page_text: preferably made vertically adjustable in reference to the stand for convenience
of viewing, and for bringing the figures into the most favorable light. The
cylinder is made open at the top to admit the light upon the figures, and may
be either closed or open at the bottom. Narrow vertical slots or apertures
are formed in the circumference of the cylinder extending about half the length
of said cylinder, and are formed a sufficient distance apart to give the figures,
when the said cylinder is revolved, a life-like appearance. Several persons
arranged around the apparatus may view the figures at the same time, to each
of whom they will appear to move naturally. The figures are formed nearly
in a line on a strip of paper or other suitable material, the length of the strip
being sufficient to extend around the interior circumference of the cylinder or
drum. The width of these strips is equal to about half the length of the
cylinder, and they are placed below the slots so as to be seen at the opposite
side of the cylinder when viewed through the said slots. Each figure varies
slightly from the contiguous ones either in form or position, and as viewed
through the apertures of the cylinder while revolving the figures make a rapid
succession of impressions upon the retina of the eye, producing the optical
illusion of moving or life-like figures. When the number of figures on the
strips is equal to the number of slots or apertures in the cylinder or drum the
figures will appear to remain in the same place relative to the cylinder,
although making a variety of gestures or movements. When the number of
figures is less than the number. of slots then the figures will appear to move
forward around the cylinder, and when the number of figures is greater than
the number of slots the figures will appear to move backward around the
cylinder. The effect mentioned depends upon viewing a succession of properly
drawn figures through apertures in the circumference of a revolving drum, the
said figures being so formed and arranged that one entire revolution will
produce one or more complete movements.
It will be seen that the combinations and movements which this apparatus
is capable of producing are unlimited.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Watson Hallett in the Great Seal Patent Office on
the 5th September 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I. HENRY
WATSON HALLETT, of Springfield, Massachusetts, United States of America,
now of No. 8, Southampton Buildings, Chancery Lane, in the County of
Middlesex, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of March, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Watson Hallett, Her special licence that T, the said Henry
Watson Hallett, my executors, administrators, and assigns, or such others
as I, the said Henry. Watson Hallett, 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 MODE OF AND MEANS FOR PRODUCING OPTICAL ILLUSIONS," upon
the condition (amongst others) that I, the said Henry Watson Hallett,
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 Henry Watson Hallett, 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, reference being had to the accompanying Sheet of Drawings
forming a part of this Specification:-
The nature of the said Invention consists chiefly, first, in the employment of
a revolving cylinder or drum with slots or apertures in its circumference for
the purpose of exhibiting figures or designs placed around the interior
circumference; and, second, in forming the figures or designs nearly in a line
upon a straight strip of paper or other material, said figures being so formed
and arranged in relation to each other that when the cylinder is revolved they
will present, viewed through the slots, the appearance of moving or life-like
figures. The cylinder is constructed of any suitable size and material, and is
mounted upon a stand, on which it is made to freely revolve. The cylinder is
preferably made vertically adjustable in reference to the stand for convenience
of viewing, and for bringing the figures into the most favorable light.
cylinder is made open at the top to admit the light upon the figures, and may
be either closed or open at the bottom: Narrow vertical slots or apertures
are formed in the circumference of the cylinder extending about half the length
of said cylinder, and are formed a sufficient distance apart to give the figures
The

page_text: when the said cylinder is revolved, a life-like appearance.
Several persons
arranged around the apparatus may view the figures at the same time, to each
of whom they will appear to move naturally. The figures are formed nearly
in a line on a strip of paper or other suitable material, the length of the strip
being sufficient to extend around the interior circumference of the cylinder or
drum. The width of these strips is equal to about half the length of the
cylinder, and they are placed below the slots so as to be seen at the opposite
side of the cylinder when viewed through the said slots. Each figure varies
slightly from the contiguous ones either in form or position, and as viewed
through the apertures of the cylinder while revolving the figures make a
rapid succession of impressions upon the retina of the eye, producing the optical
illusion of moving or life-like figures. When the number of impressions or
diagrams of a figure on the strip is equal to the number of slots or apertures
in the cylinder or drum the figures will appear to remain in the same place
relative to the cylinder, although making a variety of gestures or movements.
When the number of the said impressions is less than the number of slots then
the figures will appear to move forward around the cylinder, and when the
number of these impressions is greater than the number of slots the figures
will appear to move backward around the cylinder. The effect mentioned
depends upon viewing a succession of properly drawn figures through apertures
in the circumference of a revolving drum, the said figures being so formed and
arranged that one entire revolution will produce one ог more complete
movements.
It will be seen that the combinations and movements which this apparatus
is capable of producing are unlimited.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a plan of the top of my improved apparatus; Figure 2 is a side
elevation of the same; Figure 3 represents a portion of one of the strips.
Like letters indicate the same parts in cach of the Figures.
The revolving cylinder A is made of suitable diameter to receive the strips B
of paper or other material upon which the figures are represented, allowing
the edges of the said strips to meet or slightly overlap each other, so that the
apparent motion of the figures may be continuous. The depth of the said
cylinder must be such as will allow the said strips to lie below the vertical
apertures or slots A¹ through which the figures are viewed while in motion.
The circular portion of the cylinder A is advantageously formed of paper or
card, and is strengthened or stiffened by a metal hoop A2 on its upper edge.
The said cylinder is preferably closed at its lower end by a wood bottom, which

page_text: forms a support for the picture slips and also for the metal rod or spindle C
whereon the cylinder rotates. The said spindle is formed with a screw thread at
its upper end, and is thereby secured in the nut D, which is fixed in the centre of
the cylinder bottom. A wing nut E or other suitable device is also provided to
secure the spindle C in the nut D, and to allow the cylinder to be conveniently
adjusted upon the said spindle; the latter is fitted to turn freely in the
socket F, which is formed upon or securely attached to the base or stand G.
This socket is made of sufficient depth to form a firm support for the cylinder A
and keep it in a proper vertical position while rotating. The socket and stand
may be made of wood or metal, or partly of both, and the said socket may be
provided with bushes G to form bearings for the spindle C. The lower end
or step of the said spindle is preferably made conical, and the diameter of the
said spindle is made as slight as practicable in order to reduce the friction
between the same and its bearings, and thereby allow the cylinder to turn more
freely. The strips or bands B upon which the figures are delineated are
preferably formed of rather thick stout paper, and the figures or objects may
be printed, drawn, or otherwise produced on one or both sides of the same. A
series of impressions or representations of any given figure or object is required
to produce the apparent motion of the said figure. These impressions are
arranged at regular intervals from end to end of the strips, and each impression
represents the figure in a slightly different position or attitude, as shown on
the portion of the strip Figure 3. These diffèrent positions are such as would
be successively assumed by a figure moving in the manner represented during
one revolution of the cylinder A. As the latter revolves the impressions or
diagrams of the figure being exhibited pass in one direction before the eye,
while the slots A' pass in the opposite direction. When viewed at a proper
distance through the said slots the whole of the diagrams or inpressions of the
figures are seen in succession through each of the slots, and the apparent
movement of the figures is produced with greater or less rapidity according to
the velocity imparted to the revolving cylinder.
In witness whereof, 1, the said Henry Watson Hallett, have hereunto
set my hand and seal, this Twenty-eighth day of May, in the year of our
Lord One thousand eight hundred and sixty-seven.
HENRY WATSON HALLETT. (L.S.)