LENSES GLASSES AND THE LIKE CHIEFLY FOR SIGNAL PURPOSES to be as follows
Year: 1884

page_text: I WILLIAM WALTER LAVARACK 14 Upper Parliament Street Liverpool, Civil
and Mechanical Engineer do hereby declare the nature of the said invention for
"LENSES GLASSES AND THE LIKE CHIEFLY FOR SIGNAL PURPOSES to be as
follows:-
"
Considerable difficulty has been experienced on railways in obtaining a blue
signal light which shall not appear red at certain distances or white when the light
flickers and it has been found impossible to obtain this by merely colouring the
lense.
Now I have found by experiment that I can obtain the desired result by placing
behind or in conjunction with the ordinary lense a sheet of glass of a different
colour. Thus the ordinary blue lense is really a purple and I place behind this a
transparent sheet (preferably of glass) of what is known as a peacock blue, or blue
green, and thus obtain a colour which has no red it.
The above is given as an instance only as the colours may be varied.
This invention may of course be applied to flat glasses or spectacles as well as to
lenses,

page_text: I, WILLIAM WALTER LAVARACK, Civil and Mechanical Engineer of 14 Upper
Parliament Street, Liverpool in the County of Lancaster, England, do hereby
declare the nature of my invention for LENSES, GLASSES AND THE LIKE and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
By the invention a colored signal light is produced by the placing behind, or
before, a colored lens, one or more sheets of glass, or other transparent substance,
of a different color or colors to the lens; or by the placing behind, or before, a white
lens two, or more, sheets of glass, or other transparent substance, of different colors
Such sheet or sheets of glass, or other transparent substance, may be separate
from, or be affixed to, the lens.
For instance: A blue signal light is produced by the manufacture of lenses and
flat glasses in the following manner :-
(a) A blue lens is coated or cased on one or both sides with a layer of green
glass.
(b) A green lens is coated or cased on one or both sides with a layer of blue
glass.
(c) A white lens is coated or cased on one or both sides with a layer of both
blue and green glasses.
(d) A white lens is coated or cased on one side with a layer of blue glass and on
the other side with a layer of green glass.
(e) A flat blue glass is coated or cased on one or both sides with a layer of green
glass.
(f) A flat green glass is coated or cased on one or both sides with a layer of blue
glass.
(g) A flat white glass is coated or cased on one or both sides with a layer of both
blue and green glasses.
(1) A flat white glass is coated or cased on one side with a layer of blue glass
and on the other side with a layer of green glass.
In like manner by the use of other colored lenses and glasses, differently colored
signal lights can be obtained.
The coats or casings of glass, referred to under the headings lettered a to h, are
affixed to the lenses and flat glasses in the course of the manufacture of the lenses
and flat glasses-Preferably this is the best mode of producing colored signal lights
by my invention, but the mode of manufacture of the lenses and flat glasses with
the coatings or casings affixed as in the ordinary manufacture of glass for ornamental
purposes is not claimed by me in this or any other specification.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
For the obtaining of colored signal lights applicable to Railways, Tramways,
Shipping and such like purposes :-
1 The placing behind or before a colored lens, or colored flat glass, one or more
sheets of glass, or other transparent substance, of a different color to the
lens or flat glass.
Such sheet or sheets of glass, or other transparent substance, may be separate
from, or be affixed to, the lens or flat glass.

page_text: 2-The placing behind or before a white lens, or white flat glass, two or more
sheets of glass, or other transparent substance, of different colors.
Such sheets of glass, or other transparent substance, may be separate from, or be
affixed to, the lens or flat glass.
Nothing in this Specification has any reference whatever to the mode or manner
in which the lenses or flat glasses are artificially illumined.
Dated this seventh day of January 1885.
WILLIAM W. LAVARACK.