IMPROVEMENTS IN OPERA GLASSES,
Year: 1863

page_text: LETTERS PATENT to Samuel Hickling Parkes, of the Firm of James
Parkes and Son, of Birmingham, in the County of Warwick, Manu-
facturers, for the Invention of "IMPROVEMENTS IN OPERA GLASSES,
PROVISIONAL SPECIFICATION left by the said Samuel Hickling Parkes
at the Office of the Commissioners of Patents, with his Petition, on
the 31st October 1863.
I, SAMUEL HICKLING PARKES, of the Firm of James Parkes and Son, of
Birmingham, in the County of Warwick, Manufacturers, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN OPERA GLASSES,
TELESCOPES, MICROSCOPES, SPECTACLES, AND OTHER OPTICAL INSTRUMENTS," to be as
follows:-
My Invention has for its object to prevent the heat and irritation in the
eyes which commonly attend the use of such optical instruments as are
brought near the eye in use, and consists of the improvements herein-after
described in constructing the said instruments or such portions of them as are
brought near the eyes in using the said instruments.
When the optical instrument has an eye piece or eye lens, as in the case of
opera glasses, telescopes, and microscopes, I make the lens which is presented
to the eye of a diaphanous substance having a power of conducting heat
greater than that of glass, such, for example, as pebble or rock crystal. By

page_text: the use of such a material the heat radiated from the eye is not retained on
the surface of the lens to be radiated back again to the eye, but is conducted
through the substance of the lens, and is in part radiated from the side most
distant from the eye. I also insert between the lenses of the eye piece or
between the eye piece and the object glass a lens or plate of tinted glass
having the power of intercepting more or less the rays of yellow light, which
said rays are most irritating to the eye. The said tinted lens may also be
made to assist in correcting the spherical aberration of the other lenses.
In spectacles and other optical instruments usually made of single lenses, I
employ a compound lens, the said compound lens consisting of a pebble or rock
crystal lens and a tinted glass lens. I prefer to cement the pebble or rock
crystal lens and the tinted lens together by Canada balsam, but I do not
confine myself to this arrangement.
In using optical instruments constructed according to my Invention the
eyes are not distressed by the heat and irritation commonly attending the use
of optical instruments made in the ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Samuel Hickling Parkes in the Great Seal Patent Office
on the 25th April 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
HICKLING PARKES, of the Firm of James Parkes and Son, of Birmingham,
in the County of Warwick, Manufacturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of October, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Samuel Hickling Parkes, Her special licence that I, the said Samuel
Hickling Parkes, my executors, administrators, and assigns, or such others as
I, the said Samuel Hickling Parkes, 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 "IM-
PROVEMENTS IN OPERA GLASSES, TELESCOPES, MICROSCOPES, SPECTACLES, AND OTHER
OPTICAL INSTRUMENTS," upon the condition (amongst others) that I, the said
Samuel Hickling Parkes, my executors or administrators, by an instru-

page_text: 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 Samuel Hickling Parkes, 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:-
My Invention has for its object to prevent the heat and irritation in the
eyes which commonly attend the use of such optical instruments as are brought
near the eye in use, and consists of the improvements herein-after described in
constructing the said instruments or such portions of them as are brought near
the eyes in using the said instruments.
When the optical instrument has an eye piece or eye lens, as in the case
of opera glasses, telescopes, and microscopes, I make the lens which is pre-
sented to the eye of a diaphanous substance, having a power of conducting
heat greater than that of glass, such, for example, as pebble or rock crystal.
By the use of such a material the heat radiated from the eye is not retained
on the surface of the lens to be radiated back again to the eye, but is con-
ducted through the substance of the lens, and is in part radiated from the side
most distant from the eye. I also insert between the lenses of the eye piece,
or between the eye piece and the object glass, a lens or plate of tinted glass,
having the power of intercepting more or less the rays of yellow light, which
said rays are most irritating to the eye. The said tinted lens may also be
made to assist in correcting the spherical aberration of the other lenses..
In spectacles and other optical instruments usually made of single lenses, I
employ a compound lens, the said compound lens consisting of a pebble or
rock crystal lens and a tinted glass lens. I prefer to cement the pebble or
rock crystal lens and the tinted lens together by Canada balsam, but I do not
confine myself to this arrangement.
In using optical instruments constructed according to my Invention the eyes
are not distressed by the heat and irritation cominouly attending the use of
optical instruments made in the ordinary manner.
:
Having explained the nature of my Invention, I will proceed to describe
the manner in which the same is to be performed.
In carrying my Invention into effect with regard to the eye pieces of opera
glasses, telescopes, microscopes, and other optical instruments having eye
pieces composed of two or more lenses, I make the lens which in use is pre-

page_text: sented to the eye of pebble or rock crystal or other diaphanous substance
having a power of conducting heat greater than that of glass. I make the
said pebble or rock crystal lens in the ordinary manner, altering the curves of
the said lens to such an extent as may be necessary to give it the same power
of refracting light as the lens of glass in place of which it is substituted, as is
well understood by makers of optical instruments. Where the eye piece is
achromatic a change in the curves of the glass lens or lenses may in some
cases be necessary in consequence of the low dispersive power of the pebble or
rock crystal, as is well understood by makers of optical instruments. The lens
or plate of tinted glass which I insert between the eye piece and object glass
or between the lenses of the eye piece for the purpose of intercepting the
rays of yellow light I prefer to make of a gray or neutral tint colour or of a
neutral tint approaching to blue. When I use a plate of tinted glass having
plane parallel sides, I prefer to insert it between the eye piece and object glass.
When I employ a lens of tinted glass I prefer to make it one of the lenses
of the eye piece. In this case I either make the said tinted lens to replace
one of the lenses ordinarily employed in the eye piece, or I make it an
additional lens, giving the surface such curves as will cause it to correct more
or less the spherical aberration of the other lenses. The precise nature of the
curves to be given to the said tinted lens depends upon the curvature of the
other lenses, and require to be adjusted thereto according to the principles
well understood by makers of optical instruments.
In applying my Invention to spectacles and optical instruments usually
made of a single lens, I construct the said instruments of a compound lens,
the said compound lens consisting of a pebble or rock crystal lens and a lens
of tinted glass. I prefer to cement the two lenses together by Canada
balsam or other transparent cement, but the said lenses may be combined
without being cemented together.
In using optical instruments constructed according to my Invention the
eyes are not distressed by the heat and irritation commonly attending the use
of optical instruments made in the ordinary manner. The use next the
eye of the rock crystal or other diaphanous substance having a power of
conducting heat greater than that of glass prevents in a great measure the
irritation due to heat, and the use of the tinted glass lens or plate prevents
the irritation produced by yellow light.
Having now described the nature of my Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do not
limit myself to the precise details herein described, as the same may be varied
without departing from the nature of my Invention; but I claim as my

page_text: Invention of improvements in opera glasses, telescopes, microscopes, spec-
tacles, and other optical instruments,―
Firstly, making the lens which in use is presented to the eye in eye
pieces of opera glasses, telescopes, microscopes, and other optical instruments
having eye pieces of pebble or rock crystal or other diaphanous substances
having a power of conducting heat greater than that of glass, as herein-before
described.
Secondly, inserting between the lenses of the eye pieces of opera glasses,
telescopes, microscopes, and other optical instruments having eye pieces, a
plate of tinted glass of a colour that will intercept the rays of yellow light, or
placing the said plate of tinted glass between the eye piece and object glass
of the said instruments, or making one of the lenses of the eye piece of the
said tinted glass, or adding to the said eye piece an additional lens made
of the said tinted glass, as herein-before described.
Thirdly, making spectacles or other optical instruments usually made of a
single lens of a compound lens, the said compound lens consisting of a lens of
pebble or rock crystal or other diaphanous substance having a power of con-
ducting heat greater than that of glass, and a tinted glass lens which will
intercept the rays of yellow light, as herein-before described.
In witness whereof, I, the said Samuel Hickling Parkes, have hereunto
set my hand and seal, this Twenty-third day of April, in the year
of our Lord One thousand eight hundred and sixty-four.
5
SAMUEL HICKLING PARKES. (L.S.)
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.