IMPROVEMENTS IN REFLECTORS FOR DIFFUSING LIGHT
Year: 1853

page_text: LETTERS PATENT to Marc Louis Adam Tarin, of Mount Street,
Grosvenor Square, in the County of Middlesex, for the Inven-
tion of "IMPROVEMENTS IN REFLECTORS FOR DIFFUSING LIGHT."
Sealed the 30th July 1853, and dated the 31st January 1853.
PROVISIONAL SPECIFICATION left by the said Marc Louis Adam
Tarin at the Office of the Commissioners of Patents, with his
Petition, on the 31st January 1853.
I, MARC LOUIS ADAM TARIN, of Mount Street, Grosvenor Square,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN REFLECTORS FOR DIFFUSING LIGHT"
to be as follows: -
and
This Invention consists in constructing glass reflectors of a new
and peculiar form, whereby I am enabled to diffuse the rays of light
uniformnly over a much larger space in proportion to the size of the
flame than the reflectors hitherto employed for such purpose,
this I effect by forming the inner surface of the reflector partly
concave and partly hollow, or of an irregular or compound curve,
whilst the outer surface of such reflector is of a regular or simple

page_text: curve; but, in order to illustraté the form; I, will proceed to describe
the Drawing annexed hereto. Fig. 1, exhibits a section of a reflector
constructed according to this Invention: Fig. 2, is an outside view
to
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thereof; A, A, marks the inner surface thereof; B, the outer surface.
The letters, a, b, denote the points or centre from, which the curved
surface A, A¹, is described and produced, the letter, c, being, that

page_text: point at which the curves form a tangent to each other; and; although
I have only exhibited cone, diagrambto illustrate my. Invention, I.
desire it to be understood that I do not intend to limit, or confine
myself.to the precise form of curve there shewn; as the radii of such
curves may be varied without departing from the principle: upon'
which this Invention is based; at the same time it is important that
the lower portion A of the inner surface of the reflector.be of a
convex form, and the upper portion thereofo oftau.concave. form,
whatever be the radii of the curves by which the inner surface of
the reflector is produced; and as in practice I have found the power
of refraction to be the greatest when the, lower portion of the inner
surface of the reflector is convex and the other sportion.concave,
whilst the outer surface is a regular curve; I declare this >my.Inven-
tionsto consist in making reflectorse ofathe! combined forms herein-
before particularly described,<set forth, and representedanili srit of
levi sols to attel, bass copi
et ei tudt
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SPECIFICATION in pursuance of the conditions, of the Letters
Patent; filed by the said Marc Louis Adam Tarin in the Great
dfil inishi.
at Seal Patent Office on the 30th July, 1853.
922 192al doumavo via to od
TO ALL TO WHOM THESE PRESENTS SHALL.COME, I,
119130 20 10 3 SC! 9 10 929 07 m.
MARC LOUIS ADAM TARIN, of Mount Street, Grosvenor Square, in
ATOMT 17 100 to :
the County of Middlesex, send
of a song
most equos aasichids plugin:
Majesty Queen Victoria, by Her
mot
WHEREAS Her
Letters Patent, bearing date the Thirty-first day of January, in
the year of Lord One
our
hundred and fifty-three, in
997 "o wailed vice
the sixteenth year of Her reign, did, for Herself, Her heirs and succes-
DISE 10
sors,
14
thousand eight
Her
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grant unto me, the said Marc Louis Adam Tarin
bio: do 3d soare
Tarin, my executors,
1 license that I, the
STO! TO
Marc Louis Adam
2
administrators, and assigns, or such p
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Louis
the said Mad
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Adam Tarin, my, executors, administrators, and, assigns, should at
OVER EST dobro.976; signo
any time agree with, and no others, from time to time, and at all
91, boguide,
times thereafter during the term therein expressed, should and law.
1

page_text: fully 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 REFLECTORS FOR DIF
FUSING LIGHT," upon the condition (amongst others) that I, the said:
Marc Louis Adam Tarin, by an instrument in writing under my hand
and seal, 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 Marc Louis Adam Tarin, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer
tained in and by the following statement thereof, and by reference
to the illustrative Drawing hereunto, annexed, and the numeral
figures and letters of reference marked thereon respectively as
follows, that is to say:---------
My Invention consists in constructing reflectors of glass, or other
transparent or semi-transparent material, in such manner as that,.
when applied to the flame of a lamp or gas burner, or to any other
artificial light, the refractive power of such reflector shall be such as
to diffuse the rays of the light uniformly over a much larger space
in proportion to the size of the flame than the reflectors as hitherto
constructed; or in other words,, it consists in constructing reflectors
of variable thickness throughout instead of an uniform thickness as
usually practised, which I effect in the following manner, that is to
say: I form the inner surface of the reflector partly convex and
partly hollow, or of a compound curve or curves, and I make the
outer surface thereof of a convex form, whether the contour of said
outer surface be such as would be produced by an arc of a circle
described from one centre, or the junction of two or more arcs of
circles described from different centres, as illustrated by the diagram
at Figure 1; but I have found in practice that the best results have
been obtained when the section of the outer surface of the reflector
is that of an arc of a circle described from one centre only; I do

page_text: not, however, intend to limit or confine myself to the precise forms
of curves here shewn, as the radii of the arcs by which they are pro-
duced may be varied without departing from the principle of my
said Invention. I would also observe, that in practice I have found
the power of refraction to be the greatest when the. lower portion of
the inner surface of the reflector has been convex, the upper. portion
thereof concave, and the outer surface a regular convex curve. But
in order to explain my said Invention as completely as possible, I
will proceed to describe. the best means I am acquainted with for
carrying. the same into practical effect, réferencé being had to the
illustrative Drawing hereunto annexed, and to the nuineral
figures and letters of reference marked thereon respectively, as
duced may be varied without departing from the principle.or my
said Invention. I would also observe, that in practice I have found
the power of refraction to be the greatest when the. lower portion of
the inner surface of the reflector has been convex, the upper. portion
thereof concave, and the outer surface: a regular convex curve. But
in order to explain my.said Invention as completely as possible, I
will proceed to describe. the best means I am. acquainted with for
carrying. the same into practical effect, réference being had to the
illustrative Drawing hereunto annexed, and to the nuineral
figures and letters of reference marked thereon respectively, as
follows:-
DESCRIPTION OF THE DRAWING.
Figure 1, is a diagram illustrative of the principle. upon which I
construct reflectors according to my said Invention. Figure 2, is
an elevation of a reflector. complete. Figure 3, is a transverse and
vertical section thereof, taken through the line A, B, at Figure 2.
Figures 4, 5, and 6, are sections of reflectors of modified forms of
construction to that before described, and represented at Figures 1,
2, 3. Figures 4, and 5, are intended to be applied to a small flame
such as the flame of a candle. Figure 6, is a reflector to be applied
to lanterns. At each of these figures I employ similar letters of
reference to denote corresponding parts, in so far as such parts
appear or can be seen at each of the figures respectively. At
Figure 1,.a, b, denote the points or centres from which the arcs c,
and d, are described and thereby produce the inner or compound
curved surface A, A¹; e, being the point at which the arcs form a
tengent to each other; and f, that point or centre from which the
arc g, is described, and thereby produces the outer surface of the
reflector. I now proceed to describe the manner in which these re-
flectors may be constructed; namely, I employ a hollow metal mould
formed of two parts, which are hinged or otherwise connected
together so as to ensure their inner surfaces coming opposite to
DESCRIPTION OF THE DRAWING.
Figure 1, is a diagram illustrative of the principle. upon which I
construct reflectors according to my said Invention. Figure 2, is
an elevation of: a reflector. complete. Figure 3, is a transverse and
vertical section thereof, taken through the line A, B, at Figure 2.
Figures 4, 5, and 6, are sections of reflectors of modified forms of
construction to that before described, and represented at Figures 1,
2, 3. Figures 4, and 5, are intended to be applied to a small flame
such as the flame of a candle. Figure 6, is a reflector to be applied
to lanterns. At each of these figures I employ similar letters of
reference to denote corresponding parts, in so far as such parts
appear. or can be seen at each of the figures respectively. At
Figure 1,.a, b, dénote the points or centres from which the arcs c,
and d, are described and thereby produce the inner or compound
curved surface A, A¹; e, being the point at which the arcs form a
tengent to each other; and f, that point or centre from which the
arc g, is described, and thereby produces the outer surface of the
reflector. I now proceed to describe the manner in which these re-
flectors may be constructed; namely, I employ a hollow metal mould
formed of two parts, which are hinged or otherwise connected
together so as to ensure their inner surfaces coming opposite to

page_text: and flush with each other; the inside of the mould is of the shape
which it is desired to form the outer surface of the reflector, and the
inner surface of said reflector is produced by inserting a metal core
or plunger within the said mould, so that when the molten metal is
run into the mould, the plunger being depressed, gives to the re-
flector the desired shape. I deem it unnecessary to give a Drawing
f this mould, as the construction thereof being similar to the metal
moulds commonly used in casting articles in glass, will be well un-
.derstood by practical glass manufacturers. And I would observe,
that I have found it desirable in practice to warm the mould before
running the molten metal therein, to prevent the sudden chilling of
the metal, which produces ridges on the surface as well as destroys
the polish thereon and consequently injures the refractive power of
the reflector; I would, however, remark that this mode of constructing
reflectors with the before mentioned compound curved surfaces will
only be found to answer when the internal configuration of the
reflector is such as will enable the before mentioned plunger to be
withdrawn after it has given the shape thereto, as exhibited at
Figures 4, and 5. As for those reflectors in which the middle portion
of the interior thereof is of greater diameter than the openings at
top and bottom thereof; as at Figure 3, in such case I propose forming
the reflectors by hand; that is to say, the workman takes a lump of
metal and making a hole therein blows it into a spherical form in
the manner usually practised by glass blowers; after which he applies
a tool of the same shape as that which the inner surface of the
reflector is required to be, and with this tool the operator removes
the parts marked a, a, and continues to operate with such tool until
the inner surface of the reflector is of the same curvature as said
tool; and if necessary the outer surface of the reflector may also be
shaped by a tool in a similar manner to the inner surface; after which
the reflectors are annealed in the manner usually practised, and
this applies also to reflectors when cast or formed in a mould as
before mentioned. If desirable, these reflectors may be polished, so as
to remove any asperities therefrom, as also such of the irregularities

page_text: in the shape as would destroy or injure the refractive power of the
reflector.
Having now described the nature of my said Invention, and in
what manner the same is to be and may be performed, I claim, as
of my Invention, the constructing of reflectors in the manner
hereinbefore particularly described, set forth, and represented by
the illustrative Drawing hereunto annexed, whereby the refractive
power of the reflector is increased, and thereby constitutes "Im-
provements in Reflectors for Diffusing Light."
In witness whereof, I, the said Marc Louis Adam Tarin, have
hereunto set my hand and seal, this
day of
July, in the year of our Lord One thousand eight hundred
and fifty-three.
15 Witness,
MARC LOUIS ADAM TARIN. (L.S.)
RICHARD WM. WINDLE,
Alcester.