IMPROVEMENTS IN SIGNAL LAMPS AND LANTERNS
Year: 1883

page_text: LETTERS PATENT to Joseph Rogers of No 16 Hanover Square in the County
of Middlesex for an Invention of "IMPROVEMENTS IN SIGNAL LAMPS AND
LANTERNS "
PROVISIONAL SPECIFICATION left by the said Joseph Rogers at the Office
of the Commissioners of Patents on the 26th February 1883.
JOSEPH ROGERS of N° 16 Hanover Square in the County of Middlesex
"IMPROVEMENTS IN SIGNAL LAMPS AND LANTERNS
"
In the Provisional Specification filed by me on the 19th February 1883 N° 908
I described a construction of lenses for signal lamps and lanterns wherein a disc
of colored glass was introduced between the contiguous flat or slightly concave
surfaces of two plano-convex lenses. Since the filing of my said Provisional
Specification I have discovered that the coloring medium may be applied in
various other ways in combination with lenses so as to afford similar advantages
to those therein mentioned. Thus according to my present improvements I
arrange the two plano-convex lenses with their two convex surfaces facing each
other, or with the convex surface of the one lense facing the plane or concave
surface of the other, and I place the colored or stained glass between the two as
before, or I make the one lense a double convex lense and the other a plano-convex
lense, or they may be both double convex lenses; or lenses of any other known
form suitable for the above named purpose may be used and instead of having only
two such lenses, there may be three or more with two or more discs of colored or
stained glass between them. Or, according to another modification, one of the
lenses may be made of colored or stained glass while the other is of white glass,
or the one lense may be of white glass coated or "flashed" on one or both sides
with colored glass, and the coating, flashing or inlaying with colored glass may
be effected either over the entire surface, or only at certain parts thereof; or the
one lense may be hollow, and filled with a colored liquid that will not be affected
by the degree of heat to which the lense is subjected. Or according to another
improvement a lense such as a dioptrio lense, or a prismatic lense may be divided
Duins C31

page_text: at any point of its thickness, and the colored or stained glass be introduced
between the two parts, either as a separate disc or sheet or as a colored stratum on
one. or both parts.
According to another improvement, instead of combining the colored or stained
glass with the lense or lenses, I provide the lamp burner with a chimney or globe
of glass of the required color. Or I impart the required color to the reflector or
reflecting surfaces of the lamp, either by coating them with colored glass or
enamel or otherwise. Thus in the case of ships lights in which the sides of the
lamp form an angle with each other and act as reflectors, these sides may be so
colored, and the metal flange which overlaps the edges of the curved lense may 1
also have its inner surface made as a colored reflecting surface, reflecting the light
that strikes upon it back against the reflector of the lamp.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Joseph Rogers in the Great Seal Patent Office on the 22nd August
1883.
1.
+
JOSEPH ROGERS of N° 16 Hanover Square in the County of Middlesex,
"IMPROVEMENTS IN SIGNAL LAMPS AND LANTERNS
33,
г )
For signal lamps and lanterns that are required to transmit colored light, such
as are used on railways, ships and for other purposes, it has been customary to
construct the lenses of glass of the color required, and such color, more particularly
the green, has the detrimental effect of greatly reducing the light transmitted
through the lense.
Now according to my present invention, I obviate this defect by employing in
place of the lens of colored glass, a lense of white glass formed in two parts, so as
to constitute a compound lens, and I introduce between the two parts or lenses, a
disc or sheet of glass of the required color, or I form on one or both the contiguous
surfaces of the two lenses, a layer or coating of colored glass, the three parts thus
combined. being secured together, and. forming a compound lens that will transmit
light of the desired color as effectively as a lens of white glass will transmit white
light. In some cases the two lenses may be fixed together with a narrow space
between them into which a loose disc of colored glass is inserted.
Instead of having only two such lenses, there may be three or more with two or
more discs of colored or stained glass between them. Or, according to another
modification, one of the lenses may be made of colored or stained glass, while the
other is of white glass, or the one lens may be of white glass coated or "flashed ".
on one or both sides with colored glass, and the coating, flashing, or inlaying with
colored glass may be effected either over the entire surface, or only at certain parts
thereof; or the one lens may be hollow and filled with a colored liquid that will
not be affected by the degree of heat to which the lens is subjected. Or, according
to another improvement, a lens, such as a dioptric lens or a prismatic lens, may be
divided at any point of its thickness, and the colored or stained glass be introduced
between the two parts, either as a separate disc or sheet or as a colored stratum on
one or both parts.
The lenses employed for the purpose of my invention may be of any known
form that will transmit light to a distance and they may be either dioptric, or
prismatic or spherical.
On the accompanying drawings I have shewn various forms of such lenses.
Fig. 1 shews a section of a double convex lens composed of two meniscus (or they
may be plano-convex) lenses A A with a flat disc of colored glass B B between
them; Fig. 2 shews a combination of two plano-convex lenses A A, or on both of
whose plane surfaces are coated or flashed with glass of the required color. Fig. 3
shews one combination of a double convex lens A with a meniscus lens A¹, and a
disc of colored glass B between them, having a curvature corresponding to that of
the contiguous surfaces of the two lenses. Or the lens A may be concavo-convex
as indicated by dotted lines at A³, instead of double convex. Fig. 4 shews a double
convex lens A combined with a plano-concave lens A' and a corresponding curved
disc of colored glass B; Fig. 5 shews two plano-convex lenses A A fixed together
in a frame C, with a narrow space between them, into which is loosely inserted. &
disc of colored glass B.
Having thus described the nature of my invention and in what manner the
same is to be performed, I wish it to be understood that I am aware that signalling
lamps are commonly used on railways having an ordinary white glass lens in