IMPROVEMENTS IN TINTED OR COLORED LENSES FOR SPECTACLES OR EYE-GLASSES
Year: 1871

page_text: LETTERS PATENT to Thomas Atwood Willson, of the City of Reading,
County of Berks, and State of Pennsylvania, United States of
America, for the Invention of "IMPROVEMENTS IN TINTED OR COLORED
LENSES FOR SPECTACLES OR EYE-GLASSES."
Sealed the 1st December 1871, and dated the 6th July 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Atwood
Willson at the Office of the Commissioners of Patents, with his
Petition, on the 6th July 1871.
I, THOMAS ATWOOD WILLSON, of the City of Reading, County of
Berks, and State of Pennsylvania, United States of America, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN TINTED OR
COLORED LENSES FOR SPECTACLES OR EYE-GLASSES," to be as follows:-
:-
The nature of my Invention consists in the process of preparing the
tinted or colored lenses by graduating the alloy or coloring matter so
that when the glass is cut into lenses the tint of the thick glass or
higher magnifying power will be of the same color as those of a lower

page_text: magnifying power in which the glass is required to be thinner through
the centre.
The object is to make the tinted or colored lenses colorless to the
eye of the wearer, while the same tint, color, or shade will be the same
in the different focal numbers of spectacles or eye-glass lenses.
I use finely manufactured white optical glass. To one hundred parts.
of this mass I add one part of manganese, and about one-third in weight
of chromium to that of the manganese; this will produce a certain
shade of a pink tint for the lower or lesser focal power of the lenses,
but when the same quantities and mixture are used for a thicker lens
(at the centre of the glass) of a higher focal power the shade of color
is darker, and for every one or more additional inches of the distance or
focal power of the lenses of the higher numbers of greater magnifying
powers I add more of the colorless optical glass so as to diminish and
lighten the shade of the lens when graduating the color of lens to a
lower number, and I attain the required and proper tint by thus
manipulating the mass. I now cast the composition into a mould about
two and a half inches square by four inchos in length instead of
blowing it into sheets as usual. After the annealing of the ingot it
is reheated and flattened endwise by pressure, so as to bring the grain
at right angles to the surface of the glass, and when re-annealed it is
ready to be made into lenses in the usual manner. This position of
the grain renders the colored glass apparently white to the cyc of the
wearer when set in a spectacle frame, thus affording case and comfort
to the eye by relieving it of the effect of the bright penetrating rays
of light.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Atwood Willson in the Great Seal Patent
Office on the 2nd January 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS 30
ATWOOD WILLSON, of the City of Reading, County of Berks, and State
of Pennsylvannia, United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of July, in the year of our
Lord One thousand eight hundred and seventy-one, in the thirty-fifth 3

page_text: year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Atwood Willson, Her special
licence that I, the said Thomas Atwood Willson, my executors, admi-
nistrators, and assigns, or such others as I, the said Thomas Atwood
Willson, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 TINTED OR COLORED LENSES FOR SPECTACLES OR EYE-
GLASSES," upon the condition (amongst others) that I, the said Thomas
Atwood Willson, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and scals, 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 Thomas Atwood Willson, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement (that is to say) :-
:-
The nature of my Invention consists in the process of preparing the
tinted or colored lenses by graduating the alloy or. coloring matter so
that when the glass is cut into lenses the tint of the thick glass or
higher magnifying power will be of the same color as those of a lower
magnifying power, in which the glass is required to be thinner through
the centre.
The object is to make the tinted or colored lenses colorless to the
cyc of the wearer, while the tint, color, or shade will be the same in
the different focal numbers of spectacles or eye-glass lenses.
I use finely manufactured white optical glass. To one hundred parts
of the mass I add one part of manganese, and about one-third in weight
of chromium to that of the manganese; this will produce a certain
shade of pink tint for the lower or lesser focal power of the lenses, but
when the same quantities and mixture are used for a thicker lens (at
the centre of the glass) of a higher focal power the shade of color is
darker, and for every one or more additional inches of the distance or
focal power of the lenses of the higher numbers of greater magnifying

page_text: powers I add more of the colorless optical glass, so as to diminish
and lighten the shade of the lens when graduating the color of lens
to a lower number, and I attain the required and proper tint by thus
manipulating the mass. I now cast the composition in a mould about
2 inches square by four inches in length instead of blowing it into
sheets as usual. After the annealing of the ingot it is re-heated and
flattened endwise by pressure so as to bring the grain at right angles
to the surface of the glass, and when re-anncealed it is ready to be made
into lenses in the usual manner. This position of the grain renders
the colored glass. apparently white to the eye of the wearer when set
in a spectacle frame, thus affording case and comfort to the eye by
relieving it of the effect of the bright penetrating rays of light.
.
Having described the nature of my Invention and the manner of
performing the same, I declare that what I claim as my Invention to
be protected by the herein-before in part recited Letters Patent is,
making the pink tint or colored lens of a uniform color or shade in the
different focal numbers of spectacles or eyeglass lenses, so that each
and every number has a like tint and appears colorless to the eye of the
wearer, as herein described and set forth.
In witness whereof, I, the said Thomas Atwood Willson, have here-
unto set my hand and seal, this Twenty-ninth day of December,
in the year of our Lord One thousand eight hundred and
seventy-one.
THOMAS ATWOOD WILLSON. (L.S.)