AN IMPROVED PROCESS OF SILVERING MICA FOR USE IN THE CONSTRUCTION OF REFLECTORS AND REFLECTING SHADES
Year: 1873

page_text: ·LETTERS PATENT to Edward Otto Woerteler, of Castle Street, Falcon
Square, in the County of Middlesex, for the Invention of "AN
IMPROVED PROCESS OF SILVERING MICA FOR USE IN THE CONSTRUCTION OF
REFLECTORS AND REFLECTING SHADES."-A. communication from abroad
by William Marot Marshall, of the City of Philadelphia, in the
PROVISIONAL SPECIFICATION left by the said Edward Otto Woorteler
at the Office of the Commissioners of Patents, with his Petition,
on the 27th September 1873.
I, EDWARD OTTO WOERTELER, of Castle Street, Falcon Square, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "AN IMPROVED PROCESS OF SILVERING MICA FOR USE IN THE CONSTRUCTION OF
REFLECTORS AND REFLECTING SHADES," a communication to me from abroad
by William Marot Marshall, of the City of Philadelphia, in the State of
Pennsylvania, United States of America, to be as follows:-
I take clean mica, that is to say, as free from metallic deposit as
possible, and commence by first washing it in nitric acid and then well

page_text: rinsing it in water, after which it is placed in vats of earthenware, stone,
or other ware, iron or porcelain lined, the size of which would vary
according to the quantity and size of the mica to be operated on, but
should be of a capacity to hold from 100 to 200 pieces each.
The sheets of mica are placed vertically and back to back in pairs and 5
endwise in the vats, leaving a small space between each pair, so that
only one side of each gets coated.
When the pieces are properly arranged in the vats the latter are filled
up with the following solution, the quantity of which must vary in
accordance with the capacity of the vats, but the relative proportions of 1
the several ingredients forming it are unchanged, and are an essential
feature in the Invention.
As example I shall here mention the proportions for silvering a small
quantity of mica only:-I place 1 oz. of nitrate of silver in a bottle
containing 1 quart of pure water and allow it to fully dissolve. In 1
another bottle, also containing 1 quart of pure water, I dissolve 1 oz. of
glucose (grape sugar).
When the nitrate of silver is dissolved I pour in a small quantity of
pure aqua ammonia, this will have the effect of making the clear solution
of a muddy appearance. I then add a little more ammonia till the 2
solution again clears; the 'contents of the two bottles are then mixed
and the whole poured into the receptacle containing the mica. These
proportions being adhered to in larger quantities the vats are filled up,
and when full they should be placed in a warm place to encourage
deposit.
When the mica is sufficiently coated it is withdrawn from the vats, is
thoroughly rinsed with water, and hung up to dry, after which it may be
coated with spirit varnish, or if carefully handled it is unnecessary.
2
The frames on which the mica thus prepared is placed may be of tin,
sheet iron, paper, or plastic composition of any desired form. For 3
instance, for a parabola light a plaster form may be used, and strips of
stout paper having been cut into the proper sections they are pasted
over one another to the required thickness to give the requisite strength.
The inside being then laid off in sections the mica may be cut to accom-
modate itself to the curves, and it may be fastened with small tacks, the 3
pieces overlapping so that the tacks are invisible, the pieces being
largest at tlio inside edge and gradually narrowing towards the apex.

page_text: Shades and overhead lights may be made of metal pressed into
squares and curves, the mica being cut into strips reaching from the
outer to the inner edge, the metal being turned up at each edge to hold
the mica securely in its place.
The body of a head light should have the requisite holes for the
stem of the lamp and chimney, which should be provided with a metal
ring or rim round them to protect the edges of the mica that have been
cut round the openings.
The inside of the form may be made waterproof by painting and
frosting with sand.
As the surface of the reflectors is not tarnishable it can be used in
situations where it would be impossible to use reflectors that would
require cleaning. Hence large ceiling reflectors may be made many
feet in diameter, and as the flexibility of the material admits of bending
it in any desired curve accurate designs can be made requiring only a
small number of gas jets.
Glass and metal reflectors as now in use being plain and not pro-
jecting and diffusing light, as in the case of the mica reflectors, a
greater quantity of gas is required.
The difference in the number of lights in some instances may be
estimated as from 20 burners for the mica to 100 for the old system.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Edward Otto Woerteler in the Great Seal Patent
Office on the 26th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
OTTO WOERTELER, of Castle Street, Falcon Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of September, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Edward Otto Woerteler, Her
'

page_text: special licence that I, the said Edward Otto Woerteler, my executors,
administrators, and assigns, or such others as I, the said Edward Otto
Woerteler, 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 PROCESS OF SILVERING MICA FOR USE IN THE CONSTRUCTION OF
REFLECTORS AND REFLECTING SHADES," a communication to me from abroad
by William Marot Marshall, of the City of Philadelphia, in the State of
Pennsylvania, United States of America, upon the condition (amongst
others) that I, the said Edward Otto Woerteler, my executors or admini-
strators, 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 per-
formed, 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 Edward Otto Woerteler, do hereby.
declare the nature of my said Invention, and in what manner the 2
same is to be performed, to be particularly described and ascertained in
and by the following statement :-
I take clean mica, that is to say, as free from metallic deposit as
possible, and commence by first washing it in nitric acid, and then well
rinsing it in water, after which it is placed in vats of earthenware, stone, 2
or other ware, iron or porcelain lined, the size of which would vary
according to the quantity and size of the mica to be operated on, but
should be of a capacity to hold from one to two hundred pieces of mica
each.
The sheets of mica are placed vertically in pairs and endwise in the a
vats, leaving a small space between each pair, so that only one side of
each gets coated.
"
When the pieces are properly arranged in the vats the latter are filled
up with the following solution, the quantity of which must vary in
accordance with the capacity of the vats, but the relative proportions of 3
the several ingredients are unchanged and are an essential feature in the
Invention.

page_text: As example I shall here mention the proportions for silvering a small
quantity of mica only:-I place 1 oz of nitrate of silver in a bottle
containing 1 quart of pure water and allow' it to fully dissolve. In
another bottle, also containing 1 quart of pure water, I dissolve 1 ounce
of glucose (grape sugar).
When the nitrate of silver is dissolved I pour in a small quantity of
pure aqua ammonia, this will have the effect of making the clear solution
of a muddy appearance. I then add a little more ammonia till the
solution again clears; the contents of the two bottles are then mixed
and the whole poured into the receptacles containing the mica. These
proportions being adhered to in larger quantities the vats are filled up, and
when full they should be placed in a warm place to encourage' deposit.
$
When the mica is sufficiently coated it is withdrawn from the vats, is
thoroughly rinsed with water and hung up to dry, after which it may be
coated with spirit varnish, or if carefully handled it is unnecessary.
The frames on which the mica thus prepared is placed may be of tin, .
sheet iron, paper, or plastic composition, of any desired form. For
instance, for a parabola light a plaster form may be used, and strips of
stout paper having been cut into the proper sections they are pasted
over one another to the required thickness to give the requisite strength.
The inside being then laid off in sections the mica may be cut to accom-
modate itself to the curves, and it may be fastened with small tacks, the
pieces overlapping so that the tacks are invisible, the pieces, being
largest at the inside edge and gradually narrowing towards the apex.
Shades and overhead lights may be made of metal pressed into squares
and curves, the mica being cut into strips reaching from the outer to the
inner edge, the metal being turned up at each edge to hold the mica
securely in its place.
The body of a head light should have the requisite holes for the stem
of the lamp and chimney, which should be provided with a metal ring
or rim round them to protect the edges of the mica that have been cut
round the openings.
The inside of the form may be made waterproof by painting and
frosting with sand.
As the surface of the reflectors is not tarnishable it can be used in
situations where it would be impossible to use reflectors that would

page_text: require cleaning. Hence large ceiling reflectors may be made many
feet in diameter, and as the flexibility of the material admits of its being
bent in any curve desired accurate designs can be made requiring only a
small number of gas jets.
Glass and metal reflectors as now in use being plain and not pro- {
jecting and diffusing light as in the case of the mica reflectors a greater
quantity of gas is required.
The difference in the number of lights in some instances may be
estimated at 20 burners for the mica reflectors, and 100 for the old
system.
Having thus described my Invention and the mode of carrying the
same into effect, what I claim and desire to secure by Letters Patent is,
the construction of mica reflectors and reflecting shades, in the manner
and by the process substantially as and for the purposes herein-before
mentioned, as also for the manufacture of reflecting letters, for which
the substance is well suited.
In witness whereof, I, the said Edward Otto Woerteler, have here-.
unto set my hand and seal, this Twenty-fourth day of March,
in the year of our Lord One thousand eight hundred and seventy-.
four.
E. O. WOERTELER. (L.S.)
Witness,
A. C. HENDERSON,
Patent Agent,
6, Southampton Buildings,
Holborn,
W. C.